**4. Mortality, growth impairment an other classic tools**

Despite their traditional use for the toxicity assessment of a large number of substances, mortality and growth impairment endpoints have been extensively used to describe the toxicity of pharmaceutical substances towards wild biota. In fact, more than reflecting real scenarios of contamination, the validity of calculating and interpreting mortality data relies on the establishment of sublethal toxicity criteria and to analyse in comparative terms, the ecotoxicity of substances that act by unknown (or largely uncharacterised) mechanisms of toxic action. In fact, LC50 values of pharmaceutical drugs are well suited to establish rankings of ecotoxicity among very distinct compounds, and these criteria are straightforward to imple‐ ment and interpret. However, these endpoints are not a first choice if one requires the establishment of complex mechanisms, or even effects at extremely low levels, which are likely to cause alterations other than death, immobilization, or impairment of the population growth. These responses are not fine tuned alterations, and may be seen as blunt tools for toxicity characterization, with poor of even null ecological relevance.

The number of ecotoxicity studies analysing lethality or growth impairment is thus consider‐ able. The study published by Carlsson et al. [45], showed that antiparasitic drugs could exert extreme toxicity, when compared to antibiotics, thus threatening the survival of zebrafish embryos. The crustacean species *Daphnia magna* was very sensitive to the antidepressant sertraline, as shown by Minagh et al. [46]; this compound was capable of inducing strong alterations in the population of this crustacean species, after 21 days of exposure. Population changes were also observed after chronically exposing *D. magna* to the compounds testosterone and 4-hydroxyandrostenedione, even for ecologically relevant levels [47], reinforcing the possibility of exertion of deleterious effects in the wild. Another crustacean, namely *Neocaridina denticulate*, demonstrated to be extremely sensitive in terms of lethality to a combination of pharmaceutical drugs (paracetamol and ibuprofen) commonly found in the aquatic environ‐ ment [48]. The ecotoxicological effects of mefenamic acid on *D. magna* and *Moina macrocopa* were evaluated by Collard et al. [49]. This study showed that lethal effects were not likely to occur for already reported levels of this compound; however, the chronic exposure to this compound showed that changes in reproduction are possible, especially in the case of *M. macrocopa*.

On the other hand, the absence of potential risk posed by the presence of clofibric acid was evidenced by the study by Nunes et al. [50] and by Emblidge and DeLorenzo [51], in multi‐ species assessments that focused on mortality and growth impairment as toxicity endpoints. Similarly, the work by Ferreira et al. [52] evidenced the absence of potential lethal effects posed by antibiotics (oxytetracycline and florfenicol) on the crustacean species *Artemia parthenogene‐ tica*. Despite not exerting lethal effects, several combinations of pharmaceutical drugs (includ‐ ing an ecologically relevant mixture) were capable of causing significant alterations in zebrafish embryos, as shown by Madureira et al. [53]. The antibiotic oxytetracycline was shown to be reasonably safe towards the fish species *Labeo rohita*, since the lethal levels were well above concentrations that are not likely to be found in the wild, as shown by Ambili et al. [54].

Growth of autothrophic organisms is another endpoint likely to respond to exposure to human use drugs; the study conducted by Berninger et al. [55] showed the refractivity of the aquatic plant species *Lemna minor* to the drug diphenhydramine. Somewhat similarly, the work conducted by Nunes et al. [56] evidenced the occurrence of an oxidative-based response of two species of the genus *Lemna* (*L. minor* and *L. gibba*) elicited by the drug paracetamol, which resulted in significant growth alterations. On the other hand, the study conducted by Ferreira et al. [52] presented evidences concerning the toxicity of the antibiotics oxytetracycline and florfenicol on the microalgae species *Tetraselmis chuii*.


4.5.1. General Properties and Multi-Wavelength Observations

The (isotropic equivalent) prompt emission energy inferred from spectral analysis of Fermi-GBM data is *Eγ*,*iso* = (1.1 ± 0.2) × 1050 erg [202]. The prompt duration is *T*90 = 9.78 ± 3.47 s (15–350 keV band). The BAT time-average spectrum in the time interval 0–10 s is well fitted by a power-law model with a photon index *βT* = −3.03 ± 0.68, suggesting a low peak energy *Ep* < 10 keV [203].

Swift-XRT [204] follow-up the event starting only 3214 s after *T*0 due to observational constraints. The light curve up to almost 1 day is well described by a power-law with decay index *α* = −1.49+0.24 −0.21. Late-time observations performed by the Chandra X-ray Observatory [205] and Swift-XRT [206] from ∼8 days up to ∼21 days showed a flattening of the X-ray light curve, i.e., a flux level inconsistent (higher) with the extrapolation of the power-law decay rate at early times. Optical observations confirmed the presence of an afterglow counterpart from around 168 s [207]. The optical light-curves showed a clear initial rise with a peak around 200 s followed by a decay [208]. A bright radio counterpart (flux density ∼1.3 ×10−4 Jy at 6 GHz 1.4 days after the burst) was also detected by several instruments [209–211]. Late-time optical observations identified an associated supernova rising from 5 days after the burst reaching its maximum flux around 12–20 days after *T*0 [212,213]. The measurement of the redshift was reported by the GTC (*z* = 0.426) [214] and then confirmed by the NOT (*z* = 0.423) [215] instrument.


**1. Introduction**

New cements contains double oxides and aluminates of calcium, barium, stroncium. The date obtained allow to classify new cements as high-property fire-proof, quick-hardening and high-strength binders. The synthesis of cement clinker takes place through solid phase reactions. The newer developed cements of the higest fire resistance show only insignificant loss of strength when being heated (15% to 20% by weight), which can be accounted for by formation of high temperature - proof epitaxial contacts between the new hydrate formations and double oxides grains.

The aim of this work is to enlarge our knowledge about this new cements and hightemperature composites on them and find answers to questions about the optimum application of this product in severe industrial conditions and to analyse how this material performs in high temperatures.

The composite before trials investigated with the help of roentgen - structural and roentgen - spectral of the analyses, optical and raster electronic microscopy on standard techniques.

### **2. The using of high temperature composites based on zirconia's cement in recycling and catcher of fuel**

For coating of high temperature gas - dynamic of channels (> 2000 °C) used high temperature composites based on zirconia's cements. The properties and structure of a material are adduced in table 1, 2. The erosive and temperature stability of a material on a bench, special energies heat treatment channel a bench was previously evaluated. The test specifications are adduced in table 3.

Complex three-component source structure, durables maintenance at temperatures exceeding not only temperature of a sintering, but also the melting aluminates of barium (- 2100K) and the sintering of a dioxide of a zirconium, intensive of component's evaporation making of cement in a combination to large gradients of temperature result in steep changes on width of lining of a structure and structure of a material. It, naturally, is reflected in strength and reliability of maintenance of lining, that stipulates necessity of a detail research of a formed structure, in particular for detection of zones destruction.

New Cements and Composite Materials Based on Them for Atomic Industry 5

Parameter Tank of the combustion

Temperature of products of combustion, K 2600 - 2700 2500 - 2650 Flow velocity, m/s 80 700 Pressure (absolute), MPa 0,25 0,25-0,15

The zirconium cement in an outcome of interaction with a water is subjected hydratation with derivation of a number of connections (BaAI2O4·6H2O, BaAI2O4·7H2O, BaAI2O4·2H2O, Ba2AI2O5·5H2O), carrying on which among are two and six-water aluminates of barium. The accretion of chips of hydrat phases results in creation of a frame ensuring strength of a material at room temperature. The developed link between partial's of cement and filler at

this stage is absent. The porosity of a material after hardening makes 15-2 mass-%.

Fig. 1. Dependence of refractoriness and strengh from contents.

At temperatures is lower 400 K a material does not undergo changes. In remaining sites happens dehydratation knitting. Above 1400 T is observed a sintering of a material. Thus in a zone, which hot boundary corresponds to temperature 1700 K, the sintering happens mainly at the expense of development of contacts between partials of cement, in a zone up to 2150 K - at the expense of link of partials of cement among themselves and to grains of a

natural gas, kg/s 2-5

mass - % 40 Temperature of a heating of an oxidizer, K 1100 Coefficient of excess oxidizer 0,85-1,05

Expenditure of products of combustion of

Volumetric share of oxygen in an oxidizer,

Table 3. Specification of a test of lining.

chamber (CC)

Site a channel

Table 1. Properties of zirconia's cements.

Table 2. Physical and technical properties of composites materials based on zirconiur cements.

The composite material from a dioxide of a zirconiumipn cement contains a filler from stabilized cubic ZrO2 and cement including 30 mass-% of monoaluminates and 70 % of zirconat. A dioxide of a zirconium making 80 % of concrete, is represented by three fractions: large (0.2 – 2.5 mm), average (0.1 – 0.5 mm), small-sized (are more sma!l-sized (more finely) than 0.1 mm), including with the linear sizes of partials 1-5 microns. Used in experiments a dioxide of a zirconium was stabilized 6-7 mass-% oxide yttrium.

Table 3. Specification of a test of lining.

4 Materials Science and Technology

1 15 25 55<PHONE_NUMBER> 2 15 55 90 400 540 900 3 15 65 98 190 400 520 4 13 70 105 170 280 330 5 13 86 120 150 200 240 6 12 29 63 180 280 480 7 12 62 98 150 250 290 8 12 75 110 140 240 350 9 12 79 130 120 240 320 10 15 30 98<PHONE_NUMBER> 11 15 60 90 450 600 950 12 15 70 105 210 450 600 13 13 78 115 200 310 350 14 12 91 125 180 250 270

Baddeleyite (ZrO2) 90 80 70 Refractoriness, K 2673 2473 2073 Compression strength cold, MPa 38 45 65

burnt at 120°C 29 38 57 burnt at 300°C 17 34 39 burnt at 500°C 19 32 46 burnt at 800°C 23 37 44 burnt at 1000°C 36 39 63 burnt at 1200°C 38 44 52 burnt at 1400°C 39 45 50 burnt at 1600°C 40 47 56 burnt at 1750°C 42 45 58 Linear change, 1750°C, mass-% 1.1 1.7 2.0 Temperature of initial deformation under load, °C, no less 1750 1660 1560 Thermal shocr resistance 1300 - water heat changes, no less 16 15 11 Table 2. Physical and technical properties of composites materials based on zirconiur

The composite material from a dioxide of a zirconiumipn cement contains a filler from stabilized cubic ZrO2 and cement including 30 mass-% of monoaluminates and 70 % of zirconat. A dioxide of a zirconium making 80 % of concrete, is represented by three fractions: large (0.2 – 2.5 mm), average (0.1 – 0.5 mm), small-sized (are more sma!l-sized (more finely) than 0.1 mm), including with the linear sizes of partials 1-5 microns. Used in

experiments a dioxide of a zirconium was stabilized 6-7 mass-% oxide yttrium.

min Strength, N/mm2

Properties Content of binder / mass - %

start end 2nd 4 th 8 th

day day day

10 20 30

Setting time,

No Water to

solids, % by weight

Table 1. Properties of zirconia's cements.

Compression strength, MPa

cements.

The zirconium cement in an outcome of interaction with a water is subjected hydratation with derivation of a number of connections (BaAI2O4·6H2O, BaAI2O4·7H2O, BaAI2O4·2H2O, Ba2AI2O5·5H2O), carrying on which among are two and six-water aluminates of barium. The accretion of chips of hydrat phases results in creation of a frame ensuring strength of a material at room temperature. The developed link between partial's of cement and filler at this stage is absent. The porosity of a material after hardening makes 15-2 mass-%.

Fig. 1. Dependence of refractoriness and strengh from contents.

At temperatures is lower 400 K a material does not undergo changes. In remaining sites happens dehydratation knitting. Above 1400 T is observed a sintering of a material. Thus in a zone, which hot boundary corresponds to temperature 1700 K, the sintering happens mainly at the expense of development of contacts between partials of cement, in a zone up to 2150 K - at the expense of link of partials of cement among themselves and to grains of a

New Cements and Composite Materials Based on Them for Atomic Industry 7

Because of grains of a filler will be derivates of partials dioxide of a zirconium, inclu a grain

In accordance with transition to even more cold sites the decrease of the size of grains, of the filler which has undergone dispergation is observed. Dispergation of large grains of a filler happens in a hot part, which width makes approximately 60 - 65 mass-% from width of a zone of porous ceramics. In underlying zones in large grains of a filler the increase S of a porosity registers in comparison with source. In more small-sized grains the growth of a porosity is combined with splitting on blocks. The latter will be realized(sold) mainly near to boundaries of a grain of a filler. As well as in hotter sites, in a material the developed contacts of grains of a filler with decristallisation by partials of a small-sized fraction are

The link between large by dispergation grains of a filler implements derivations of a complex configuration generated from partials of average and small-sized fractions dioxide of a zirconium. A structure of these derivations, number and quality of contacts, explicating between them and large grains of a filler, largely determine strength of a material in a zone of porous ceramics because of dioxide of a zirconium. Their most characteristic variants of allocation of structural units in intervals between large grains it is necessary to mark a

The hot part of a zone of porous ceramics differs from hot sites less by rectangular distribution of a material and large size of vacuum in intervals between grains of a filler. Thus the fair quantity porosity, oriented along a hot surface is observed. In some cases the concentration such nop on approximately one horizon happens, the depth makes 0.12 hS – 0.14 hS. The rise of concentration porosity carries on to lowering strength of a material on appropriate horizon. At availability change, of temperature in this area the cracks, carrying

As already it was marked, a dominating phase in a zone of porous ceramics is the cubic hard solution because of dioxides of a zirconium. The concentration of the stabilizing '' component Y2O3 in a layer, which adjoins to a hot surface, makes 3 - 4 mass-% (molar shares) ambassador 50 hours of trials. The same level of concentration of the component registers through 200 - 250 hours after a beginning of trials. In accordance with transition to more steep layers of this zone concentration Y2O3 the gradually is increased and near to cold boundary of a zone of porous ceramics receives a reference value. The not stabilized dioxide of a zirconium either is absent, or registers in an amount less than 1 %. The absence of the not stabilized dioxide of a zirconium shows, that in a hot part of this zone the reallocation of the component Y2O3 between a source cubic hard solution and not stabilized ZrO2, selected

The link of particles of a dioxide of a zirconium in a zone of porous ceramics implements mainly direct contacts ZrO2 - ZrO2. The part of contacts will be realized by means of films by

Near to cold boundary of a zone of porous ceramics the increase of number of \* inclusions zirconat of barium is observed. On depth 0.14hS – 0.16hS the sharp increase of a content zirconat of barium up to 20 - 25 mass-% (figure 1) happens, that considerably exceeds the source value - about 14 mass-%. Zirconat of barium in this area will derivate congestions on

and going to it a partial of a small-sized fraction.

structure, in which the primary orientation is absent.

on to destruction linings can develop.

happens at decomposition zirconat barium.

width a micron and less, containing oxide of a aluminum.

observed.

filler, in a more high-temperature layer the direct contacts of partials dioxide of a zirconium develop. In intermediate area (between the poorly changed zone and by a sintering layer) the structure of a material is determined by a degree dehydratation knitting, accompanying by destruction source hydro aluminates of barium. In a zone, from the cold side to sintering to a layer, where has a place practically full loss of a water, the destruction of a frame derivates, and, as a corollary it, recession of strength of a material happens. It is necessary to mark, that while in service destructions of lining on this zone, as a rule, does not happen, probably, by virtue of design features of a wall.

The width sintering of a layer depends on a level of temperature on a hot surface. At the temperature of about 2200 K the width sintering of a layer makes 20-25 mass-% from width of lining (for linings by width hS =12-60 mm), at 2300 - 2350 K 0,45 hS - 0.6 hS (on the profile of temperature partial transparency of a material) essentially influences. In a hot part sintering of a layer a sintering of a material increasing at the expense of derivation of a melt aluminates of barium. The rnelt partially quits on a firing surface of lining. The selection of a melt on a firing surface of a material during first 0,5-1 h of unisothermal heating immediately was observed during trials.

In bounds of a sintering layer it is possible to select some zones. Immediately zone adjoins to a hot surface, which distinctive feature is the presence only in the extremely minor amount (less than 1 %) components of cement. The cold boundary of this zone approximately coincides an isotherm 2200 K. by a Dominating phase a sintering layer is trie cubic hard solution because of dioxide of a zirconium. Aluminates and zirconate of barium register as separate of inclusions. Aluminates making is represented in main inclusions Al2O3. The average content BaO in a sintering layer makes 0.2 – 0.4 mass-%, Al2O3 0.3 – 0.4 mass-%.

The structure of a material of a hot layer, going to a firing surface, shows, that during trials it in main loses components of cement. Zirconat of barium is partial in other zones, is partially decomposed with selection as an independent phase Al2O3. The loss of components of cement carries on to growth of a porosity of a material in a hot layer on 5 mass-% - 8 mass-% in comparison with source.

The structure of a hot layer of lining by width 0.14 hS- 0.16 hS (here and further at the temperature of of working surface is higher 2300 K) represents sintering porous ceramics because of dioxide of a zirconium. The character of a structure, formed in this layer, is determined by a level of temperature and amount of a liquid phase at the first phase of a sintering. In to a going firing surface a layer (the hot part of a zone of porous ceramics) happens heavily division of source grains of a filler into more small-sized fragments. Present here at initial stage of trials the melt aluminates of barium, which amount can be increased at the expense of arrival from more cold sites, promotes both process dispergation, and reallocation of products dispergation and partials of a small-sized fraction on size. The partials of a small-sized fraction dioxides of a zirconium are intensive decristallisation. In an outcome in to a hot surface a layer the material loses obviously expressed division into large and small-sized fractions and acquires a rather homogeneous structure.

In more cold sites of a zone of porous ceramics an amount of a liquid phase present to not initial stage of trials and capable to ensure a regrouping, of a capable, much below, than in of surface area. Dispergation of grains of a filler with derivation of free interfaces between blocks is not accompanied by essential reallocation of derivate partials on size.

filler, in a more high-temperature layer the direct contacts of partials dioxide of a zirconium develop. In intermediate area (between the poorly changed zone and by a sintering layer) the structure of a material is determined by a degree dehydratation knitting, accompanying by destruction source hydro aluminates of barium. In a zone, from the cold side to sintering to a layer, where has a place practically full loss of a water, the destruction of a frame derivates, and, as a corollary it, recession of strength of a material happens. It is necessary to mark, that while in service destructions of lining on this zone, as a rule, does not happen,

The width sintering of a layer depends on a level of temperature on a hot surface. At the temperature of about 2200 K the width sintering of a layer makes 20-25 mass-% from width of lining (for linings by width hS =12-60 mm), at 2300 - 2350 K 0,45 hS - 0.6 hS (on the profile of temperature partial transparency of a material) essentially influences. In a hot part sintering of a layer a sintering of a material increasing at the expense of derivation of a melt aluminates of barium. The rnelt partially quits on a firing surface of lining. The selection of a melt on a firing surface of a material during first 0,5-1 h of unisothermal heating

In bounds of a sintering layer it is possible to select some zones. Immediately zone adjoins to a hot surface, which distinctive feature is the presence only in the extremely minor amount (less than 1 %) components of cement. The cold boundary of this zone approximately coincides an isotherm 2200 K. by a Dominating phase a sintering layer is trie cubic hard solution because of dioxide of a zirconium. Aluminates and zirconate of barium register as separate of inclusions. Aluminates making is represented in main inclusions Al2O3. The average content BaO in a sintering layer makes 0.2 – 0.4 mass-%, Al2O3 0.3 – 0.4 mass-%.

The structure of a material of a hot layer, going to a firing surface, shows, that during trials it in main loses components of cement. Zirconat of barium is partial in other zones, is partially decomposed with selection as an independent phase Al2O3. The loss of components of cement carries on to growth of a porosity of a material in a hot layer on 5 mass-% - 8

The structure of a hot layer of lining by width 0.14 hS- 0.16 hS (here and further at the temperature of of working surface is higher 2300 K) represents sintering porous ceramics because of dioxide of a zirconium. The character of a structure, formed in this layer, is determined by a level of temperature and amount of a liquid phase at the first phase of a sintering. In to a going firing surface a layer (the hot part of a zone of porous ceramics) happens heavily division of source grains of a filler into more small-sized fragments. Present here at initial stage of trials the melt aluminates of barium, which amount can be increased at the expense of arrival from more cold sites, promotes both process dispergation, and reallocation of products dispergation and partials of a small-sized fraction on size. The partials of a small-sized fraction dioxides of a zirconium are intensive decristallisation. In an outcome in to a hot surface a layer the material loses obviously expressed division into large and small-sized fractions and acquires a rather homogeneous

In more cold sites of a zone of porous ceramics an amount of a liquid phase present to not initial stage of trials and capable to ensure a regrouping, of a capable, much below, than in of surface area. Dispergation of grains of a filler with derivation of free interfaces between

blocks is not accompanied by essential reallocation of derivate partials on size.

probably, by virtue of design features of a wall.

immediately was observed during trials.

mass-% in comparison with source.

structure.

Because of grains of a filler will be derivates of partials dioxide of a zirconium, inclu a grain and going to it a partial of a small-sized fraction.

In accordance with transition to even more cold sites the decrease of the size of grains, of the filler which has undergone dispergation is observed. Dispergation of large grains of a filler happens in a hot part, which width makes approximately 60 - 65 mass-% from width of a zone of porous ceramics. In underlying zones in large grains of a filler the increase S of a porosity registers in comparison with source. In more small-sized grains the growth of a porosity is combined with splitting on blocks. The latter will be realized(sold) mainly near to boundaries of a grain of a filler. As well as in hotter sites, in a material the developed contacts of grains of a filler with decristallisation by partials of a small-sized fraction are observed.

The link between large by dispergation grains of a filler implements derivations of a complex configuration generated from partials of average and small-sized fractions dioxide of a zirconium. A structure of these derivations, number and quality of contacts, explicating between them and large grains of a filler, largely determine strength of a material in a zone of porous ceramics because of dioxide of a zirconium. Their most characteristic variants of allocation of structural units in intervals between large grains it is necessary to mark a structure, in which the primary orientation is absent.

The hot part of a zone of porous ceramics differs from hot sites less by rectangular distribution of a material and large size of vacuum in intervals between grains of a filler. Thus the fair quantity porosity, oriented along a hot surface is observed. In some cases the concentration such nop on approximately one horizon happens, the depth makes 0.12 hS – 0.14 hS. The rise of concentration porosity carries on to lowering strength of a material on appropriate horizon. At availability change, of temperature in this area the cracks, carrying on to destruction linings can develop.

As already it was marked, a dominating phase in a zone of porous ceramics is the cubic hard solution because of dioxides of a zirconium. The concentration of the stabilizing '' component Y2O3 in a layer, which adjoins to a hot surface, makes 3 - 4 mass-% (molar shares) ambassador 50 hours of trials. The same level of concentration of the component registers through 200 - 250 hours after a beginning of trials. In accordance with transition to more steep layers of this zone concentration Y2O3 the gradually is increased and near to cold boundary of a zone of porous ceramics receives a reference value. The not stabilized dioxide of a zirconium either is absent, or registers in an amount less than 1 %. The absence of the not stabilized dioxide of a zirconium shows, that in a hot part of this zone the reallocation of the component Y2O3 between a source cubic hard solution and not stabilized ZrO2, selected happens at decomposition zirconat barium.

The link of particles of a dioxide of a zirconium in a zone of porous ceramics implements mainly direct contacts ZrO2 - ZrO2. The part of contacts will be realized by means of films by width a micron and less, containing oxide of a aluminum.

Near to cold boundary of a zone of porous ceramics the increase of number of \* inclusions zirconat of barium is observed. On depth 0.14hS – 0.16hS the sharp increase of a content zirconat of barium up to 20 - 25 mass-% (figure 1) happens, that considerably exceeds the source value - about 14 mass-%. Zirconat of barium in this area will derivate congestions on

New Cements and Composite Materials Based on Them for Atomic Industry 9

In more cold sites down to cold boundary of a layer the sintering of cement happens without obviously expressed the linear change. Recristallisation of particles of cement is expressed poorly. In a material the continuous frame of cement is formed. Thus the link between a filler and cement is advanced poorly. As already it was marked, the cold

The circumscribed above zones in a sintering layer are present at the rather developed form in 2 hours after a beginning of trials. The more durables trials do not result in increase of width of a sintering layer and zones, composing it. With rise of duration of trials the zone of porous ceramics because of dioxides of a zirconium in a greater degree is cleared of inclusions containing barium and aluminum. Besides the more expressed character is

Is conducted about 20 launches of installation for trial of materials by duration from 50 till approximately 400 o'clock. During trials temperature on a surface of lining (both in the combustion chamber is fixed, and in gas-dynamic a channel), as a rule, 2250 -2400 K, in

The rise of temperature of a surface of lining Ts is precisely fixed at decrease of a share of a firing surface occupied by copper edges and at increase of width of lining h (from Ts≈2000 K at x≈0,15 and h=10 mm up to Ts≈2400 K at x≈0 and h=25-30 mm). Is marked, that at Ts >2200 K defining a role in creation of a thermal mode of a firing surface begins to play of walls among themselves (density of a heat flow ≥1 MW/m2 at density of a convective heat

At temperatures a surface of concrete is higher 2150 T concrete lining on zirconia's cement in a upper layer well conglomerated in first 2-6 hours of installation, that provided to lining high erosive stability purely erosion of a material during trials was less than 1 micron /

Is clarified, that the lining on zirconia's cement allows conduct fast (for 20 - under 60 min.) heating of an outline of installation. Moreover, such heating even is preferable to concrete (acceleration of a sintering of a high layer results in decrease of initial erosion of concrete).

**3. The using of zirconia's cement composite in coating of quartz glass tanks**  The new cements and composite based on then can be used in the coating of quartz glass tanks. In contact with glass there are used refractories made of natural baddeleyite without stabilizing oxides. The coating of this material showed good characteristics under thermal

Red mud is a waste material which results from alumina production during the Bayer process. Approx. 35-40% of the bauxite ore processed goes into waste as red mud. This is a cheap source of raw material for the manufacture of low-cost ceramic products such as building blocks, floor and wall tiles, sanitary ware and as an additive for cement. The

acquired with concentration of the poores in a cold part of a zone of ceramic porous.

boundary sintering of a layer passes on depth 0.45hs – 0.6hs.

separate experiments it was possible to reach temperature 2600 K.

shock and quartz glass penetration resistance properties.

chemical composition of red mud is as follows (Table 4).

flow ≤0.4 MW/m2).

hour.

**3.1 Red mud**

a surface of particles dioxide of a zirconium, fills in the porosity and crack in grains of a filler. The particles zirconat of barium forming on boundaries of grains dioxide of a zirconium, have the linear sizes 2-50 microns and differ by dense stacking. Sometimes such are be surrounded by a film Al2O3. The content Al2O3 in a zone of synthesis zirconat of barium makes 1.5-1.7 mass-%. Thus an amount aluminates of barium makes 1 %.

The useful increase of an amount zirconat of barium allows to assume, that the part a pair(vapour.couple) BaO selected at decomposition zirconat of barium in a zone of porous ceramics, acts to space in more cold zones, where is condensed and enters response with a dioxide of a zirconium with derivation secondary zirconat of barium. It is necessary to marRrTRaT the derivation BaZrO3 in a considered zone is also in case of absence zirconat of barium in source concrete. Thus the amount synthesized during trials zirconat of barium does not exceed 3-4 %.

The material of a zone enriched zirconat of barium, after trials is saturated with cracks. The development of cracks should be promoted by the volumetric extension accompanying synthesis zirconat of barium. The link of particles of a dioxide of a zirconium implements both by means of direct contacts, and through inclusions zirconat of barium.

In a cold part of a zone of synthesis zirconat of barium the number of inclusions aluminates of barium accrues. The amount of the latter spasmodically increases on depth 0,24hS - 0,26hS. The underlying layer by width about 0,07hS differs by an increased content aluminates of barium (12 - 15 mass-%), essentially exceeding a source level (6 mass-%). In a hot part of a zone enriched BaZrO3 , aluminates of barium in a combination to particles BaZrO3 will derivate interlayer up to 150 microns on boundaries of grains of a filler. The content zirconat of barium is close a reference value. The particles of cement differ by rather dense stacking. Their linear sizes make in main 3-15 microns. The direct contacts of particles dioxide of a zirconium here practically are absent. At the same time in this area the development of contacts of particles dioxide of a zirconium both with zirconat and with aluminates of barium is provided. The material of lining in a considered layer differs in increased density in comparison with the poorly changed zone. It is possible to assume, that the derivation of this packed zone is stipulated by arrival of a melt aluminates of barium from hot layers of lining and it a chip.

From the cold side the layer adjoins to a zone with increased density, in which the content of components of cement is identical source. The sintering of cement in this zone flows past rather actively and is accompanied of the linear change. In an outcome in intervals between grains of a filler the including also small-sized particles of a dioxide of a zirconium will be derivated densely stacked of particles of cement. The structure of a material here is identical to a structure of concrete, in isothermal conditions at 1900 -2000 K.

In accordance with deleting from a zone saturated aluminates of barium, the size of particles of components of cement of a gradually decreases, the quality of link between a filler and particles of cement is worsened. At the same time the linear change within the limits of a small-sized fraction hinders with derivation of a continuous frame of cement, that in a combination to not enough developed contacts a filler - the cement carries on to lowering strength of a material in this zone. At cooling of lining the explicating in a material of power result in derivation of trunk cracks in a cold part of a circumscribed above zone on depth, making 0.3hs – 0.4hs.

In more cold sites down to cold boundary of a layer the sintering of cement happens without obviously expressed the linear change. Recristallisation of particles of cement is expressed poorly. In a material the continuous frame of cement is formed. Thus the link between a filler and cement is advanced poorly. As already it was marked, the cold boundary sintering of a layer passes on depth 0.45hs – 0.6hs.

The circumscribed above zones in a sintering layer are present at the rather developed form in 2 hours after a beginning of trials. The more durables trials do not result in increase of width of a sintering layer and zones, composing it. With rise of duration of trials the zone of porous ceramics because of dioxides of a zirconium in a greater degree is cleared of inclusions containing barium and aluminum. Besides the more expressed character is acquired with concentration of the poores in a cold part of a zone of ceramic porous.

Is conducted about 20 launches of installation for trial of materials by duration from 50 till approximately 400 o'clock. During trials temperature on a surface of lining (both in the combustion chamber is fixed, and in gas-dynamic a channel), as a rule, 2250 -2400 K, in separate experiments it was possible to reach temperature 2600 K.

The rise of temperature of a surface of lining Ts is precisely fixed at decrease of a share of a firing surface occupied by copper edges and at increase of width of lining h (from Ts≈2000 K at x≈0,15 and h=10 mm up to Ts≈2400 K at x≈0 and h=25-30 mm). Is marked, that at Ts >2200 K defining a role in creation of a thermal mode of a firing surface begins to play of walls among themselves (density of a heat flow ≥1 MW/m2 at density of a convective heat flow ≤0.4 MW/m2).

At temperatures a surface of concrete is higher 2150 T concrete lining on zirconia's cement in a upper layer well conglomerated in first 2-6 hours of installation, that provided to lining high erosive stability purely erosion of a material during trials was less than 1 micron / hour.

Is clarified, that the lining on zirconia's cement allows conduct fast (for 20 - under 60 min.) heating of an outline of installation. Moreover, such heating even is preferable to concrete (acceleration of a sintering of a high layer results in decrease of initial erosion of concrete).


Author details

Gabriel Modukpe1 \* and Don Diei2

\*Address all correspondence to<EMAIL_ADDRESS>
© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

successfully. Tests were carried out on the system and showed that turbine speed and wind speed are proportional to power response when simulated. The generated power increases with the turbine speed, making the model useful as wind energy is generated at different wind spend, and this has been able to unveil that even at different wind speed, wind energy potential is available in the coastal area of southern Nigeria. This energy could be used for distributed generation for these

communities isolated from the grid.

Figure 17. Turbine speed.

Wind Solar Hybrid Renewable Energy System

Figure 18. Generator speed.

Figure 19. Electrical power.

64


*4.1. Analysis of LECMPAU Air Traffic and ATFCM Regulations*

Before starting to test the model and analyse its explainability, it is important to understand the operation in the Pamplona Upper (LECMPAU) sector, as well as the behaviour of the regulations in the sector. To study traffic behaviour, the methodology developed by CRIDA has been used to organise traffic into flows. The flows obtained from the methodology are presented in this paper as part of the input variables of the machine learning model will be whether there are aircraft in each flow or not. The flows are presented in Figure 4.

The air traffic flows identified have been divided into four main groups. The flows that cross the sector from north to south are of great importance in the operation of the sector, as they contain flights that normally depart from or go to the Madrid-Barajas airport. Other flows of great interest are those crossing the sector from east to west, as these will normally be associated with flights departing from or going to Barcelona-El Prat. With this, it can also be said that LECMPAU is a sector whose operation is very complex, as it includes operations around the two largest airports in Spain, making it a sector of great interest.

Additionally, there is another group of flows that cross the sector diagonally from the west of the sector to the north or vice versa. Flights belonging to these flows are more variable and difficult to classify into a single flight type.

With these air traffic flows, an attempt to characterise the traffic in the sector simply is made, taking into account the different trajectories that can be flown. In addition, it is important to characterise the regulations in the LECMPAU sector, as it will be possible to see certain patterns in the appearance of these regulations that can be used to validate the results of the machine learning model.

Overall, there were 150 regulations in LECMPAU in 2019. These regulations had a mean regulation time of 121.9 min, and a standard deviation of 71.16. To be more specific, the boxplot of the regulation time is presented in Figure 5.

**Figure 4.** LECMPAU Air Traffic Flows.

**Figure 5.** Boxplot of Regulation time in LECMPAU.

In the boxplot, it can be seen that most of the regulations have a regulation time between 50 and 200 min. There are cases of outliers due to both deficit and excess. With this data, only 18,285 min in the whole year will be regulated. This is 3.5% of the total time analysed. As the model will tell whether the sector is regulated or not, there is likely an imbalance in the sample to be analysed, as LECMPAU is much longer unregulated than regulated.

Rather than the duration of these regulations, it is of interest to know how they are distributed over time. This information is presented in Figure 6, which shows histograms of the regulations according to their month (a), day of the week (b), and start time (c).

**Figure 6.** Temporal analysis of regulations in LECMPAU, of hour of regulation (**a**), month of regulation (**b**) and Day of the week of the regulation (**c**).

The temporal analysis indicates that most of the regulations will occur in summer. This is normal, as Barcelona and Mallorca are common holiday destinations, and flights from the US to these airports will pass through LECMPAU via flows crossing the sector from east to west. This increase in traffic will lead to more capacity regulations. As for the day of the week, most of the regulations will occur on weekends, mainly on Saturdays. This is also natural, as weekend traffic will be higher than Monday to Friday. Finally, the hourly analysis indicates that regulation will be centred at 05:00, with three secondary peaks of regulation at 06:00, 15:00, and 18:00. These are the most common times for business and holiday flights.

With this information, it is possible to find patterns in the behaviour of regulations in 2019, so it is possible that the machine learning algorithm, which is mainly based on temporal variables, will find these patterns and manage to act satisfactorily. The results of the model are presented below.


**1. Introduction**

Multiple metallic structures and equipment operate in outdoor conditions [1]. In such cases, one of the main problems related to their stability and durability is corrosion [2,3]. World Corrosion Organization (WCO) estimates the world direct cost of corrosion to be between 1.3 and 1.4 trillion EUR, 3.1% to 3.5% of a nation's GDP annually [4].

Corrosion is a very complex phenomenon based on the degradation of a material or its properties due to its reaction with the environment [5]. Multiple factors [6], particles [7], and variables [8,9] are involved. The character of the attack and the corrosion rate are consequences of the system formed by metallic materials, atmospheric environment, technical parameters, and operating conditions [10]. Corrective factors are introduced in the design phases to guarantee the structure's integrity during its useful life [11]. However, the difficulty of quantifying the material loss causes unnecessary over-dimensioning, leading to superfluous costs and resources consumption [12]. Proper management of this complex multifactorial phenomenon is key to sustainable development [13].

To ensure the integrity of the outer layer, structures are designed with physical protection. Historically, metallic zinc has provided excellent corrosion protection of steel structures [14]. Unfortunately, corrosion damage also occurs in such systems [15]. Since corrosion leads to a mass loss, an excess thickness is often considered to ensure service life. This not only increases manufacturing cost but also does not satisfy the principles of sustainable engineering efficiency [16]. Therefore, lacking an automated monitoring system or predictive model, routine thickness monitoring would be required [17]. These

**Citation:** Terrados-Cristos, M.; Ortega-Fernández, F.; Alonso-Iglesias, G.; Díaz-Piloneta, M.; Fernández-Iglesias, A. Corrosion Prediction of Weathered Galvanised Structures Using Machine Learning Techniques. *Materials* **2021**, *14*, 3906. https:// doi.org/10.3390/ma14143906

Academic Editor: Marián Palcut

Received: 10 June 2021 Accepted: 12 July 2021 Published: 13 July 2021

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

**Copyright:** © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

phenomena have drawn increasing attention in recent decades due to the resulting catastrophic accidents [18] and the growing demand for sustainable designs [19]. For an optimal selection of materials, atmospheric aggressiveness must be considered. Depending on this, coating needs can be set.

The current regulation regarding galvanised metallic structures (ISO 9223:2012 [20]) groups the corrosivity level of an atmosphere into six categories. After studying the effect of corrosion on standard samples during 1 year of weathering exposure, the level of corrosion rates achieved can be established by measuring weight losses for different materials. This material's loss due to corrosion is commonly used as an initial measure for determining coating requirements. However, material loss margins are allowed within these categories, and coating thickness designs based on them are not fixed. These margins imply variability in the amount of material that can be translated into increased costs.

According to [20], two methods are proposed to classify the corrosivity of atmospheric environments, depending on the availability of experimental data. When experimental data are available, dose–response functions can be used. However, when no experimental data are available, corrosivity category estimation using the informative procedure is recommended, and as stated in the norm, it is based on the comparison of local environmental conditions with the description of typical atmospheric environments, which may cause misinterpretations [21]. Finding the optimum point between efficiency and competitive price, while remaining within limits, is therefore challenging given the lack of characterisation of the specific construction site.

The objective of this work is to develop machine learning models that, by analysing real cases, predict corrosion mass loss of zinc coatings over time. The aim is to characterise an environment without requiring long testing periods and sampling and generalising it to any location worldwide, with the data available from international studies. This considerably increases the existing knowledge about coated steel structure corrosion and extends it to the full diversity of atmospheres, thereby reducing the uncertainty of its final state.

This paper starts with a state-of-the-art analysis. Then, it explains the creation of the database through the characterisation of each sample. Next, the applied methodology is explained, and modelling and evaluation techniques are defined. Finally, results are discussed, and the conclusions obtained in this research are proposed.


**2. Plasmonic RGWN components**

The operation of RGWNs is based on two basic components: power splitting elements and isolated waveguides. While the waveguides could easily be implemented using dielectric waveguides, the power splitting elements at the intersection of two such waveguides could not be achieved using dielectrics alone. Nevertheless, this splitting operation, which is the key enabler of this technology, is native to the intersection of two plasmonic waveguides. Consequently, a possible implementation of a RGWN is by using plasmonics via a mesh of intersecting sub-wavelength air gaps in a metal matrix.

Surface plasmon polaritons (referred here to as plasmons for brevity) are slow surface waves that propagate at metal-dielectric interfaces. Adding another metal-dielectric interface to this system, results in a metal-insulator-metal (MIM) waveguide, which supports a highly confined plasmon wave (the lowest order transverse magnetic mode - TM0) that does not get structural cut-off as the dielectric gap between the metal layers becomes vanishingly small. The existence of this lowest-order plasmonic mode in MIM waveguides allows for such plasmonic components as power splitters (Feigenbaum 2007-1) and high transmission sharp waveguide bends (for a review of MIM waveguides and their possible applications see Feigenbaum 2007-2). However, the existence of metal in the MIM

designing this network layout reshapes the interference pattern and the optical function of the RGWN, as will be exemplified later in this chapter. The 2x2 RGWN consists of one closed loop resonance, however larger two- or three-dimensional networks can support

Fig. 1. Schematic illustration of (a) a 4-terminal equal power-splitting element and (b) a local

Although the concept of RGWNs is quite general, we will first illustrate the underlying physics of this paradigm using plasmonics since it allows for a simple topological implementation. After introducing this implementation, in the following sections we will demonstrate how the local wave interference can be designed to engineer small (2x2) energy storage RGWN resonators, and also how we can program the optical transmission function of inhomogeneous RGWNs using transfer matrix formalism. We will also address how the same design principles can be utilized to control the optical dispersion properties of infinitely large RGWNs that behave like artificial optical materials. After addressing other possible implementation and practical issues we will conclude with possible future

The operation of RGWNs is based on two basic components: power splitting elements and isolated waveguides. While the waveguides could easily be implemented using dielectric waveguides, the power splitting elements at the intersection of two such waveguides could not be achieved using dielectrics alone. Nevertheless, this splitting operation, which is the key enabler of this technology, is native to the intersection of two plasmonic waveguides. Consequently, a possible implementation of a RGWN is by using plasmonics via a mesh of

Surface plasmon polaritons (referred here to as plasmons for brevity) are slow surface waves that propagate at metal-dielectric interfaces. Adding another metal-dielectric interface to this system, results in a metal-insulator-metal (MIM) waveguide, which supports a highly confined plasmon wave (the lowest order transverse magnetic mode - TM0) that does not get structural cut-off as the dielectric gap between the metal layers becomes vanishingly small. The existence of this lowest-order plasmonic mode in MIM waveguides allows for such plasmonic components as power splitters (Feigenbaum 2007-1) and high transmission sharp waveguide bends (for a review of MIM waveguides and their possible applications see Feigenbaum 2007-2). However, the existence of metal in the MIM

directions and a more detailed comparison to other optical design paradigms.

multiple resonances, which give rise to more design possibilities.

resonance in a 2x2 RGWN.

**2. Plasmonic RGWN components**

intersecting sub-wavelength air gaps in a metal matrix.

waveguide configuration does add a source of a modal attenuation to the system as a result the usual loss mechanisms present in any real metal-containing system. This results in a trade off between the compression of the modal cross-section and the modal attenuation as the air gap size is decreased. Since the loss in metals is strongly frequency and material dependent, the focus here will be on RGWNs composed of Au-air-Au MIM waveguides operating at telecommunication frequencies where the modal propagation lengths are on the order of tens of microns, which are substantially larger than the propagation lengths at visible frequencies. The optical properties of the materials throughout this chapter are based on tabulated data (Palik 1998).

In this implementation, the intersection of two sub-wavelength MIM waveguides forms an X-junction that functions as the power splitting elements in the network (Feigenbaum 2007- 1) and the MIM segments between the intersections serve as the isolated waveguides connecting the X-junctions. Through this implementation, X-junctions can be tuned to split power equally at infrared wavelengths both for continuous waves and for short pulse waves consisting of only a few optical cycles while conserving the shape of the input signal. The observed equal-power split is a result of the subwavelength modal cross-section of the input plasmonic waveguide that excites the junction with a broad spectrum of plane waves. As such, equal four-way optical power splitting is enabled for transmission lines (e.g., MIM and coaxial configurations) but cannot be easily achieved using purely dielectric waveguides due to their half-wavelength modal cross-section limit. Thus, through a plasmonic implementation, the strong coupling to all four neighboring X-junctions gives the plasmonic RGWN structure an optical response different from a cross-coupled network of purely dielectric waveguides, where most of the power would be transmitted in the forward direction, with only weak coupling to perpendicular waveguides.

Fig. 2. Power splitting properties of the emerging pulses in an X-junction: (a) intensity relative to the exciting pulse, and (b) phase difference at *λ0*=1.5µm (Feigenbaum 2010).

As the MIM waveguide air gap thickness is varied, the power-split between the X-junction terminals can be tuned both in terms of amplitude and phase (Feigenbaum 2010). This, in addition to determining the phase accumulation in the waveguide segments, sets independent controls in designing the interference pattern that governs the operation of a RGWN. The power splitting in the Au-air X-junction was investigated using the 2D finitedifference time-domain (FDTD) method with short pulse excitation and two equal thickness intersecting MIM waveguides. Through this study, it was found that for small (0.25µm) MIM gaps, these plasmonic X-junctions exhibit equal power splitting with the reflected

Resonant Guided Wave Networks 49

and maintaining it inside suggests that MIM gap sizes that are subwavelength, but not arbitrarily small, will maximize the network resonance. To interpret the FDTD observations and arrive to the conclusion described above, a simplified analytical description of pulse propagation in the network is derived in which only a few parameters are tracked: phase, amplitude, position and direction. The pulses are assumed to travel in the waveguides and split into four new pulses upon arrival at an X-junction. This model also illustrates the compactness of the possible mathematical representation of RGWNs, and the importance of this advantage becomes more substantial when considering the dynamics of larger 2D and

Fig. 4. Time snapshots of *Hz* (normalized to the instantaneous maximum value) in a 2x2 plasmonic RGWN recorded at the third to the seventh power splitting events for a 2D-FDTD simulation. The MIM waveguides are 0.25µm thick and 6µm long (Feigenbaum 2010).

indicating that the resonator Q-factor is primarily limited by the material loss.

Calculating the Q-factor of such 2x2 RGWN resonators (Fig. 5) illustrates the role of interference in generating a strong network resonance, which causes the network Q-factor to be an order of magnitude larger than what would be expected if optical power splitting in the X-junctions operated incoherently, i.e. we lost half the power in each splitting event. Increasing the MIM gap size causes the phase of the interfering waves to deviate from being π-phase shifted, resulting in a degradation of the constructive interference inside the resonator and a decrease in the overall network Q-factor. On the other hand, as the gap size is decreased, the plasmonic mode attenuation increases due to metallic losses in the waveguides. Between these two competing effects, the maximal Q-factor value is obtained for a gap size of 250nm. These RGWN Q-factor values are considerable for plasmonic resonators and even comparable to typical values of wavelength-size dielectric resonators that are dominated by radiation loss (e.g., a cylindrical dielectric cavity of radius 1.3 with a purely real refractive index of n=2.5 surrounded with air has a Q~100). If we were to artificially decrease the Au loss at 1.5µm (or alternatively go to longer wavelengths), the Qfactor of the resonator would increase appreciably (e.g., Q ~ 750 for a 200 nm gap width),

3D network topologies.

pulse being out-of-phase (i.e., approximately π-phase shifted) with respect to the sideways and forward transmitted pulses. As illustrated in Fig. 2a, as the MIM gap size is increased, the optical power flow deviates from equal power splitting between the terminals towards dominant power transmission directly across the X-junction, which resembles the wavelength-scale photonic mode limit. Furthermore, in these calculations, the phase shift between the sideways (S) and the forward (F) transmitted pulses is consistent with the geometrical difference in their pulse propagation trajectories (see Fig. 2b).


*3.4. Systematic Functional Annotation of Top Differentially Expressed Genes*

To better understand the functional organization of the most relevant *E. gracilis* genes under the assayed culture conditions, we computed a network of ontologies, based on transcript expression levels across all samples and studies (Supplementary Table S7). For this purpose, we only selected GO and KEEG terms that corresponded to the 2500 most variable genes (in terms of expression) to determine which biological functions were represented and how they were related to each other. The resulting organized network contained 119 nodes, with an average of nine neighbours per node, and 436 genes from the initial 2500 genes were retained (some genes being part of multiple hubs). We then used the MCODE algorithm to find evidence of higher order organization (Figure 4). The network was composed of nine modules (or hubs), each defined by one ontological category (Supplementary Table S8). Hub number 1 (72 transcripts) reflects "regulation of DNA damage checkpoint", with transcripts involved in apoptosis, control of transcription and other developmental processes. Unlike hub number 7 (see below), hub 1 has a stress response component. Hub 2 (191 transcripts) is the largest hub, and comprises genes involved in translational initiation and termination, or protein targeting to a membrane, and is thus defined by "ribosome" terms. Hub 2 is connected to hubs 3, 5 and 6 in the network. Categorized as a "thylakoid" hub, hub 3 (133 transcripts) is the second largest hub. It mainly comprises photosynthetic electron transport chain transcripts and other components that respond to light stimuli. According to taxonomic annotation, the majority of the genes represented in this hub come from green organisms. Transcripts involved in protein kinase activity were found in Hub 4 (23 transcripts), defined as "cyclin-dependent protein serine/threonine kinase regulator activity". Hub 5 (25 transcripts) corresponded mainly to processes involved in genetic information processing, such as spliceosome, exosome, chromosome-associated proteins, or chaperones. Hub 6 (79 transcripts) is defined by several categories related to mitochondrial protein complexes and mitochondria transport, and has a central position in the network (connections to hubs 1, 2, 3 and 8). Hub 7 (46 transcripts) was defined by "DNA integrity checkpoint" ontology terms and consisted of cell cycle processes, such as transition from G1 phase to S or the previously mentioned DNA integrity checkpoint. Hub 8 (53 transcripts) was categorized as "response to temperature stimulus" and was composed mainly of transcripts that encode heat shock proteins. Components of hub 9 (22 transcripts) were related to "negative regulation of translation". Overall, our 2500 most relevant genes appear to be distributed around the central role of the mitochondrion, whose origin traces back to the euglenozoan host cell [31]. In this respect, our taxonomic analysis specifically revealed that more than 10% of genes are related to kinetoplastids (the closest available proxy for the host cell) in all hubs, except for hub 3, categorized as "thylakoid" (Supplementary Table S9).


**7. Summary**

Chen et al. [90] compared typhoon‐enhanced primary production in the SCS with that in the subtropical ocean water of the WNP during the period of 2003–2012. Their results showed that the annual mean carbon fixation induced by typhoons was more in the SCS than in the ocean water. This is because the mixed layer is thicker and the nutricline depth is deeper in the latter

The biological response to typhoons can happen not only in the surface layer but also in the subsurface. Ye et al. [93] found that a Chl‐*a* bloom appeared in the subsurface layer (20–100 m depth) of the SCS after the passage of Typhoon Nuri (2008) and lasted for three weeks. This subsurface bloom was stronger and its life was longer than the synchronous surface Chl‐*a* bloom. Previous estimates of the contribution from typhoons to annual primary production in the SCS were mostly based on the results in the surface layer using remote sensing data. On this aspect, these estimates probably underestimate the actual contribution of typhoons.

There are many wide and shallow continental shelf regions in the WNP, mostly located in the China Seas. The ecosystem in these shelf regions can become more productive after typhoons

The continental shelf of the southern ECS, northwest of Taiwan, is a typical oligotrophic and strong stratification area during summer. However, Shiah et al. [78] found that all chemical and biological parameters measured in a survey after the passage of Typhoon Herb (1996) were much larger than normal summer conditions. The typhoon caused primary production, particulate organic carbon (POC) concentration, bacterial production, and biomass to increase by at least two‐fold. Their results indicated that wind mixing, re‐suspension and terrestrial runoff associated with the typhoon were responsible for these responses. Based on multi‐ satellite observations, Chang et al. [16] showed that Typhoon Hai‐Tang (2005) induced upwelling and increased Chl‐*a* concentration in this shelf region, persisting for more than 10 days. The upwelling was likely caused by Ekman pumping due to strong typhoon wind and wind‐driven shoreward intrusion of Kuroshio water along the shelf break. Siswanto et al. [94] also demonstrated that long‐lasting southerly winds accompanying with typhoons can force Kuroshio current axis to move toward the shelf of the southern ECS, inducing upwelling. This process uplifts nutrients and then increases new productivity, which contributes 0.6–11.8% of the summer‐fall new productivity in the ECS. In addition to the effects on primary production represented by Chl‐*a*, typhoons may have influence on phytoplankton composition. Chung et al. [95] observed that a diatom bloom was induced in the southern ECS after the passage of

Typhoon Morakot (2009) and the species composition was changed also.

Zhang et al. [96] observed that the surface Chl‐*a* concentration in the continental shelf southeast of Hainan Island was increased by 38.5% after the passage of tropical storm Washi (2005). Chen et al. [97] showed that the primary productivity and nitrate‐uptake‐based new production in the upstream Kuroshio close to southern Taiwan were enhanced after the passage of three typhoons in 2007 by riverine mixing associated with the typhoons. After Typhoon Malou (2010) passed over Sagami Bay in the central part of Japan, both Chl‐*a* concentration and bacterial

in spite of its larger area and more super typhoons appearing there.

14 Recent Developments in Tropical Cyclone Dynamics, Prediction, and Detection

**6.3. In continental shelf waters**

pass through [77, 78, 87].

TCs usually change temperature and salinity vertical profiles by vertical mixing, upwelling and heat flux. Generally, the vertical mixing causes surface temperature cooling and subsurface warming. The upwelling brings cold deep water upward and makes the water temperature in the upper layer to decrease, which suppresses the subsurface warming and enhances the surface cooling. Surface sea water loses heat into air by heat flux and its temperature further decreases.

TCs typically generate energetic transient currents in the upper ocean, which modulates mean circulations such as the Kuroshio. The upper layer flow of the Kuroshio can be slowed or shut down temporarily just before a TC approaches. It can shift the location of the Kuroshio main stream. In the SCS, TCs affect both large scale and mesoscale circulations, and generate NIOs and ISWs. They change the instantaneous volume transport through a strait like the Taiwan Strait and then accumulatively modify its seasonal and annual mean transports. TCs not only influence pre‐existing oceanic mesoscale eddies but also generate cyclonic eddies when they travel slowly.

TCs produce storm surges and huge waves which can flood coastal low‐lying areas and threaten coastal structures. Because of wide continental shelves and flexural coastlines, the combination of onshore wind and low pressure accompanying with typhoons easily causes devastating storm surges along the coasts of the continent and islands in the WNP. Addition‐ ally, Ekman setup and wave setup also contribute to the storm surges in some shallow waters. In the continental shelf regions of the China Seas, coastal trapped waves are often induced and tide‐surge interaction is significant in the shallow coastal sea areas and in the Taiwan Strait.

As the most intense case of air‐sea interaction, TCs can cause biogeochemical and biological responses in the ocean. The vertical mixing and upwelling associated with TCs transport nutrients from the depths to the surface layer. As a result, phytoplankton blooms are often triggered and contribute to the primary productivity in the WNP, especially in the SCS. In continental shelf waters, the biological responses are more complex because of pre‐existing upwelling, TC‐enhanced freshwater plume, riverine mixing, terrestrial runoff, and sediment resuspension.

Since we focus on the influence of TCs in the WNP, some important aspects are not included here, such as the feedback of ocean to TCs. The accumulative effects of TCs on climate are not considered, either, because they are global and indirect, not limited to the WNP, in a long time scale. Regarding the complexity and extensiveness of ocean responses to TCs, some questions remain open and more observations and investigations are necessary to explore their answers in the future.