*2.2. Materials*

As a feedstock, we applied agglomerated TiO2 powder (TAYCA Corporation, WP0097, Osaka, Japan) containing a pure anatase crystalline structure with an average particle size of about 7.55 μm, as shown in Figure 1. The material chemical composition of substrates used is presented in Table 1.

**Figure 1.** SEM morphology of TiO2 powder.

**Table 1.** Material chemical composition [wt%].


**5. Results**

Following the high-frequency research studies of Mitchell (2010) and Knoll et al. (2018), we conducted a fully-fledged performance evaluation for the top 10 stocks of JDS from January 1998–December 2015 compared to the benchmarks BHS, FTS, GVS, and RVS. In particular, we evaluated the return characteristics and risk metrics (Section 5.1), examined the performance over time (Section 5.2), and analyzed the robustness of the strategies (Section 5.3). According to Gatev et al. (2006) and Avellaneda and Lee (2010), this paper calculated the total return based on committed capital, i.e., we divided the sum of daily net profits at the current day by the deployed capital.


**Gastrointestinal Complications in Cardiothoracic Surgery: A Synopsis**

Jennifer Schwartz, David E. Lindsey, Hooman Khabiri and Stanislaw P. A. Stawicki

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/54348


**6. Conclusions**

In this work we treated the four standard products of digraphs (the Cartesian, the strong, the direct and the lexicographic) with respect to the efficient open domination. The idea is to describe which digraphs among these products are efficient open domination digraphs and to describe them with the properties of their factors. We completely characterized such digraphs among the direct product (Theorem 8) and among the lexicographic product (Theorem 9). For the efficient open domination Cartesian product digraphs the characterizations are given for those for which the first factor has an underlying graph that is a path (Theorems 1, 3 and 4), a cycle (Theorem 2) or a star (Theorem 5). This yields an idea on how to deal with the Cartesian product of digraphs with one fixed factor and an arbitrary second one. Among the efficient open domination strong product of digraphs we characterized those in which both factors have uni-cyclic graphs as their underlying graphs (Theorems 6 and 7). We also conjecture that this are the only strong product digraphs that are the efficient open domination digraphs.

**Author Contributions:** All authors contributed equally to this work. Conceptualization, D.B. and I.P.; methodology, D.B. and I.P.; formal analysis, D.B. and I.P.; validation, D.B. and I.P.; writing—original draft preparation, D.B. and I.P.; writing—review and editing, D.B. and I.P. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was partially funded by Javna Agencija za Raziskovalno Dejavnost RS under grant numbers P1-0297 and J1-9109.

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


**3. Impact of climate change on crop production**

Global atmospheric concentrations of greenhouse gases have significantly increased relative to pre-industrial times [13, 39, 40]. As a result, greenhouse gas forcing is the main cause of the warming of the atmosphere during the past decades [14, 41, 42]. This warming is expected to substantially alter the climate system and change global food production, mainly because temperatures are predicted to increase which in turn will alter the precipitation pattern and increase the frequency of extreme events such as drought [15, 43–45]. Man-made greenhouse gas emissions as a result of industrialization and urbanization have made significant

contributions to global warming and further changes in the global climate. As a result, global temperature rose by 0.83°C from 1906 to 2010 [10]. Global warming also causes changes in precipitation levels and patterns due to higher evapotranspiration and water vapor amounts in the atmosphere with several implications for the global hydrological cycle [16, 46]. As the major water consumer of the developing world and some developed countries, agriculture is one of the most vulnerable water sectors to climate change [17, 18]. Dramatic population growth, associated with reduction of productive land area and water resources, exerts extra pressure on the agricultural sector. To ensure sustainability of agriculture, studying the possible climate change impacts on this sector is essential [9, 19, 47].

Rate of plant growth and development is dependent upon the temperature surrounding the plant and each species has a specific temperature range represented by a minimum, maximum, and optimum [48–50]. The expected changes in temperature over the next 30–50 years are predicted to be in the range of 2–3°C Intergovernmental Panel for Climate Change [10]. Heat waves or extreme temperature events are projected to become more intense, more frequent, and last longer than what is being currently been observed in recent years [51, 52]. Extreme temperature events may have short-term durations of a few days with temperature increases of over 5°C above the normal temperatures [53]. Extreme events occurring during the summer period would have the most dramatic impact on plant productivity. A recent review by Barlow et al. [54] on the effect of temperature extremes, frost and heat, in wheat (*Triticum aestivum* L.) revealed that frost caused sterility and abortion of formed grains while excessive heat caused reduction in grain number and reduced duration of the grain filling period. Analysis by [55] revealed that daily minimum temperatures will increase more rapidly than daily maximum temperatures leading to the increase in the daily mean temperatures and a greater likelihood of extreme events and these changes could have detrimental effects on grain yield. If these changes in temperature are expected to occur over the next 30 years then understanding the potential impacts on plant growth and development will help develop adaptation strategies to offset these impacts [56, 57].

Previous studies of climate change impacts on agriculture, using crop yield simulation models [9, 58–60].or statistical models suggest that climate change will substantially affect productivity of major staple food crops such as maize, because growth and development of crops are mainly dependent on sunlight, temperature, and water [22, 23, 61]. Climate change may modify precipitation, soil water, runoff, and may reduce crop maturation period and increase yield variability and could reduce areas suitable for the production of many crops [24, 62, 63]. Climate change might limit crop production (the amount of a crop that is harvested in a farm, region, state, or country in kilograms or tons) in many areas [64–66].

Temperature increases affect most plants, leading to crop yield reduction and complex growth responses [25, 46, 67]. Nevertheless, the impact of increasing temperatures can vary widely between crops and regions. For example, a 1°C increase in the growing period temperature may reduce wheat production by about 3–10% [68], winter wheat productions may be decreased by 5–35%, respectively, under the future warmer and drier conditions [21, 26], and corn yield may be reduced by 2.4–45.6% due to higher temperatures [27, 69]. Even if precipitation is unchanged, the crop production may decrease by 15% on average due to the reduction in crop growth period and increased water stress as the result of higher temperature and evapotranspiration (Schlenker et al. [63]; Yang et al. [16]; Khanal et al. [28]) expected precipitation reductions in arid and semiarid regions of the world, where water is already limited, can have dramatic impacts on crop production [32–35]. For example, in northwestern Turkey, winter wheat yield may decline more than 20% under future climate change because the growth periods can be shortened as a result

**59**

**Table 3.**

**Table 2.**

*Impact of climate change on other crop production.*

*Climate Change Impacts and Adaptation Strategies for Agronomic Crops*

of increased temperature, exacerbated by a reduction in precipitation [21, 29–31]. Higher reduction in wheat yield of 50% was found in Pakistan as shown in **Table 2**. In some other areas, climatic change might have positive influences on agricultural crop yield, i.e., in dry areas rainfall enhances under wet climatic warming can lead to improved crop productions like in Mexico the wheat yield would be increase by 25% in future (**Table 2**). Maize, rice, winter wheat and potato crop yield can be enhanced with increasing air temperature and rainfall in the Plain of North China [73]. In Ghana maize yield would be increase by 12% in future (**Table 2**). The impact of climate change on sugarcane and cotton is shown in **Table 3**. Higher reduction in cotton yield of 17% and sugarcane yield of 40% was found at USA (**Table 3**). However, some positive impacts of climate change on sugarcane yield were found in few countries such as Brazil and Australia (**Table 3**). The impact of climate change on coarse grain, oilseed and other miner crops such as pearl millet, sorghum and sesame are shown in **Table 1**. Huge reduction in coarse grain and other

**Crops Country/continent Yield reduction (%) References** Cotton China −5.5 [48]

Sugarcane Brazil +15 [70]; [65]

**Countries Coarse grains Oilseeds Other crops** China −22 to 2 −12 to 12 −22 to 2 Philippines −17 to −3 −10 to 4 −17 to −3 Thailand −17 to −3 −10 to 4 −17 to −3 Rest S+E Asia −17 to −3 −10 to 4 −17 to −3 Bangladesh −17 to −3 −10 to 4 −17 to −3 India −17 to −3 −15 to 4 −17 to −3 Pakistan −17 to −3 −15 to 4 −17 to −3 Rest S Asia −17 to −3 −15 to 4 −17 to −3

*Productivity shock due to climate change on rice, wheat, and coarse grains by 2030.*

USA −17 [49] Africa −7 [52] USA −9 [51] Pakistan −8 [53] Burkina Faso −13 [56] Australia −17 [59]

Switzerland −9 [71] Australia +20 [72] Africa +11 [46] USA −40 [66] Brazil −27 [65] India −30 [64]

*DOI: http://dx.doi.org/10.5772/intechopen.82697*

#### *Climate Change Impacts and Adaptation Strategies for Agronomic Crops DOI: http://dx.doi.org/10.5772/intechopen.82697*

of increased temperature, exacerbated by a reduction in precipitation [21, 29–31]. Higher reduction in wheat yield of 50% was found in Pakistan as shown in **Table 2**. In some other areas, climatic change might have positive influences on agricultural crop yield, i.e., in dry areas rainfall enhances under wet climatic warming can lead to improved crop productions like in Mexico the wheat yield would be increase by 25% in future (**Table 2**). Maize, rice, winter wheat and potato crop yield can be enhanced with increasing air temperature and rainfall in the Plain of North China [73]. In Ghana maize yield would be increase by 12% in future (**Table 2**). The impact of climate change on sugarcane and cotton is shown in **Table 3**. Higher reduction in cotton yield of 17% and sugarcane yield of 40% was found at USA (**Table 3**). However, some positive impacts of climate change on sugarcane yield were found in few countries such as Brazil and Australia (**Table 3**). The impact of climate change on coarse grain, oilseed and other miner crops such as pearl millet, sorghum and sesame are shown in **Table 1**. Huge reduction in coarse grain and other

#### **Table 2.**

*Climate Change and Agriculture*

contributions to global warming and further changes in the global climate. As a result, global temperature rose by 0.83°C from 1906 to 2010 [10]. Global warming also causes changes in precipitation levels and patterns due to higher evapotranspiration and water vapor amounts in the atmosphere with several implications for the global hydrological cycle [16, 46]. As the major water consumer of the developing world and some developed countries, agriculture is one of the most vulnerable water sectors to climate change [17, 18]. Dramatic population growth, associated with reduction of productive land area and water resources, exerts extra pressure on the agricultural sector. To ensure sustainability of agriculture, studying the possible

Rate of plant growth and development is dependent upon the temperature surrounding the plant and each species has a specific temperature range represented by a minimum, maximum, and optimum [48–50]. The expected changes in temperature over the next 30–50 years are predicted to be in the range of 2–3°C Intergovernmental Panel for Climate Change [10]. Heat waves or extreme temperature events are projected to become more intense, more frequent, and last longer than what is being currently been observed in recent years [51, 52]. Extreme temperature events may have short-term durations of a few days with temperature increases of over 5°C above the normal temperatures [53]. Extreme events occurring during the summer period would have the most dramatic impact on plant productivity. A recent review by Barlow et al. [54] on the effect of temperature extremes, frost and heat, in wheat (*Triticum aestivum* L.) revealed that frost caused sterility and abortion of formed grains while excessive heat caused reduction in grain number and reduced duration of the grain filling period. Analysis by [55] revealed that daily minimum temperatures will increase more rapidly than daily maximum temperatures leading to the increase in the daily mean temperatures and a greater likelihood of extreme events and these changes could have detrimental effects on grain yield. If these changes in temperature are expected to occur over the next 30 years then understanding the potential impacts on plant growth and development will help develop adaptation strategies to offset these impacts [56, 57]. Previous studies of climate change impacts on agriculture, using crop yield simulation models [9, 58–60].or statistical models suggest that climate change will substantially affect productivity of major staple food crops such as maize, because growth and development of crops are mainly dependent on sunlight, temperature, and water [22, 23, 61]. Climate change may modify precipitation, soil water, runoff, and may reduce crop maturation period and increase yield variability and could reduce areas suitable for the production of many crops [24, 62, 63]. Climate change might limit crop production (the amount of a crop that is harvested in a farm,

climate change impacts on this sector is essential [9, 19, 47].

region, state, or country in kilograms or tons) in many areas [64–66].

Temperature increases affect most plants, leading to crop yield reduction and complex growth responses [25, 46, 67]. Nevertheless, the impact of increasing temperatures can vary widely between crops and regions. For example, a 1°C increase in the growing period temperature may reduce wheat production by about 3–10% [68], winter wheat productions may be decreased by 5–35%, respectively, under the future warmer and drier conditions [21, 26], and corn yield may be reduced by 2.4–45.6% due to higher temperatures [27, 69]. Even if precipitation is unchanged, the crop production may decrease by 15% on average due to the reduction in crop growth period and increased water stress as the result of higher temperature and evapotranspiration (Schlenker et al. [63]; Yang et al. [16]; Khanal et al. [28]) expected precipitation reductions in arid and semiarid regions of the world, where water is already limited, can have dramatic impacts on crop production [32–35]. For example, in northwestern Turkey, winter wheat yield may decline more than 20% under future climate change because the growth periods can be shortened as a result

**58**

*Impact of climate change on other crop production.*

#### **Table 3.**

*Productivity shock due to climate change on rice, wheat, and coarse grains by 2030.*

crops were found in china up to 2030. However, higher losses in oilseed crops were observed at India and Pakistan as shown in **Table 1**.


*3.1. Patient Demographics and Immunohistochemistry*

GLUT1 expression was assessed in 104 patients (79 males, 25 females; median age 69 years, range 35–88 years) and correlated with patient's clinical information. All patients were diagnosed using resected primary tumors. Histologic analysis revealed that 29 patients with PPC harbored a combination of carcinomatous and sarcomatous components. In the remaining 75 primary tumors, carcinomatous components were identified in 48 patients with adenocarcinoma, 13 with squamous cell carcinoma, 8 with adenosquamous cell carcinoma, 2 with poorly differentiated carcinoma, and 4 with Pe. Of the sarcomatous components, 69 patients exhibited spindle-cell type, 10 giant-cell type, and 25 both spindle- and giant-cell types. Each percentage of epithelial and sarcomatous components is shown in Supplementary Figure S1. The day of surgery was considered the starting day for measuring postoperative survival. The median follow-up period was 476 days (range, 30–4519 days).

Patient demographics data according to GLUT1 expression are listed in Table 1. Immunohistochemical analyses were performed for 104 primary sites with PPC. GLUT1 was stained on the cell membranes of tumor specimens, and there was no evidence of normal tissue without red blood cells. Figure 1 shows the representative images of GLUT1 expression in patients with PPC. Figure 2 shows the distribution of GLUT1 expression according to a scoring system. The frequencies of scores 1, 2, 3 4, and 5 for GLUT1 were 11%, 3%, 25%, 32%, and 19%, respectively. The percentage of samples showing high GLUT1 expression was 48% (50/104). High expression of GLUT1 was found to be significantly associated with advanced stage, vascular invasion, pleural invasion, and tumor cell proliferation, as determined by the Ki-67 index. There was a significant correlation between GLUT1 expression and tumor cell proliferation according to the Ki-67 labeling index in all patients (Spearman's rank; *r* = 0.25, *p* < 0.01).

**Table 1.** Patient demographics according to GLUT1 expression.

\* *p* < 0.05 was considered statistically significant. *t*-test score was for continuous variables, and χ2 test for categorical variables.

**B**

**Figure 1.** *Cont*.

**D**

**E**

**Figure 1.** An 88-year-old male with PPC including a component of squamous cell carcinoma (**A**) GLUT1 was stained on the membrane of tumor cells, showing a score of 4. A 78-year-old female with PPC including components of squamous cell carcinoma and spindle cells: GLUT1 was stained throughout the squamous cell carcinomas (**B**) and partial lesions of spindle cells (**C**). A 77-year-old male with PPC including components of adenosquamous cell carcinoma and giant cells: GLUT1 was stained throughout the epithelial cells (**D**) and sarcomatous cells (**E**).

**Figure 2.** Distribution of GLUT1 expression according to scoring system. The frequencies of scores 1, 2, 3 4, and 5 for GLUT1 were 11%, 3%, 25%, 32%, and 19%, respectively.

Next, epithelial histological types such as adenocarcinoma (AC) and non-AC were assessed. No significant difference in the frequency of high GLUT1 expression was observed between patients with AC (20/48) and non-AC (30/56) (*p* = 0.24).


*2.1.1. Economic factors*

due to contradictions in the capitalist mode of production, which caused the conflict of accumulation and justification [1, 2]. Streeck [3] also recently argued that the 2008 global financial crisis was an inevitable consequence of an unstable combination of capitalism and democracy in capitalist countries. His argument is that the financial crisis is the result of the demolition of democratic capitalism because of capital beyond democratic control in the process of postcapitalist transition to neoliberalism in the development and reinterpretation of new Marxist

However, it is difficult to accept these claims when we remember that the recent financial crisis has not appeared in all advanced western welfare states. In particular, it is not easy to assert that the fiscal crisis of the welfare state is inevitable, considering that it is not found in the Nordic countries, which provide generous welfare benefits, but it is found in Southern Europe, where the level of welfare spending is low and the social security system is not sufficiently developed when compared to other western welfare states. Therefore, it is necessary to identify what kind of welfare state is fiscally sustainable, as well as the difference between

In fact, if the government has sufficient fiscal space and the state is able to cope with increasing debt without damaging fiscal sustainability [4] for welfare expenditures, the problem of fiscal sustainability will not rise seriously. The methods of securing financial resources include the expansion of taxes or nontax receipts, the reduction of public expenditures, the adjustment of expenditure priorities, and increase in expenditure efficiency, currency issuance, and foreign aid [5]. One of the key strategies that advanced welfare states can implement to mitigate financial tensions is to increase tax revenues or reduce welfare spending on major public expenditures. Often in high-income countries, cuts in spending are considered to be superior to revenue increases [6]. It is argued that adjustments through a reduction in public spending are less likely to lead to a recession than tax expansion and may also have a positive impact on growth. According to this assertion, the best way to ensure the fiscal sustainability of a

Although, reducing welfare spending is not the only answer to the financial crisis facing the welfare state, because cutting public spending is not always possible and feasible. Alesiana and Giavazzi [6] point out that public spending reduction strategies that are accompanied by appropriate monetary policy play an important role in sound financing, but this is not always possible. As noted, EU countries have limited monetary policies at a single national level [7]. In addition, the sudden reduction of welfare benefits often leads to opposition from the people in the form of restrictions to the government's response to the need for welfare due to new social risks, as well as political resistance from citizens who enjoyed existing welfare benefits [8, 9]. Of course, spending rebalancing and rationalization can be a useful means of securing financial resources within a given budget in the short term. However, as time goes by, marginal returns of spending rebalancing and rationalization are inevitably reduced, and

Therefore, we should focus on resource mobilization in order to secure predictable and sustainable financing [5]. This study focuses on the tax system, which is the main resource for advanced welfare countries among various resource mobilization methods. First, taxation plays an important role in ensuring national policy capacity [10]. It can also lead or inhibit capital accumulation,

claims in the present situation.

98 Taxes and Taxation Trends

fiscally sustainable countries and nonsustainable countries.

welfare state is to reduce welfare expenditures.

as a result, these are not a fundamental alternative [5].

Macroeconomic factors related to the fiscal sustainability of the welfare state include economic growth rates and interest rates, the gap between economic growth rates and interest rates, economic openness and financial market accessibility, and inflation.

At first, the fiscal sustainability of the welfare state is related to the economic growth [13–16]. If the economy grows smoothly, the tax is easily collected. In particular, progressive tax can be applied at a higher rate depending on the increase in income, so that tax rate growth is higher than the economic growth rate. In addition, inflation that accompanies economic growth can lead to a substantial decline in debt value, because debt is a nominal asset, and its value is fixed and transferred to the future. In the low growth phase, however, tax revenue was limited, and real debt burdens were likely to increase. In addition, due to the decrease in income, the debt burden was sure to increase.

The effects of interest rates on national debt have also been important [13, 16]. In the context of the emphasis on interest rates, some studies have focused on the initial level of debt [17, 18]. This is because countries with high initial debt have high interest rates on national debt, and their fiscal capacity is sensitive to changes in interest rates [19]. Therefore, there is a greater risk that fiscal sustainability will be weaker than that found in countries with low debt level.

Meanwhile, some studies have demonstrated that primary balance is important [14, 20]. Sakuragawa and Karou [14] examined the phenomenon that the real interest rate on government bonds is low, while the national debt surge is comparable to the gross domestic product in developed countries as well as Japan by incorporating the concept of intermediation cost is explained. Specifically, government bonds are not very sensitive to interest rate changes because intermediation costs lower deposit interest rates and bond return replaces deposits. Therefore, they argued the interest rate was not the primary factor, but, rather, the level of the primary balance.

Some have paid attention to access to markets where the government can borrow money [21–24]. Drelichman and Voth [23] attempted to account for the fact that eighteenth-century England, whose financial position was worse than Spain's in the sixteenth century, did not face insolvency. Specifically, England was able to borrow at a lower rate of interest than the market interest rate through financial repression, so the cost of interest was low. Thus, the interest burden on repayment of government bonds could be significantly reduced. Moreover, with financial globalization, the government took notice not only of the domestic market, but also the foreign market. In particular, low-income countries with low financial capacity can reduce the burden of foreign debt by improving access to financial markets due to globalization [13, 22, 24], while developed countries do not have a statistically significant impact of the global capital market on fiscal sustainability [24].

At first, decentralization has become a major concern in terms of the decision-making structure of fiscal policy. When there are a large number of participants in the decision-making process, each participant may represent only a narrow range of interest groups. Therefore, it may not be easy to reach consensus due to conflicting interests among participants. Indeed, if there is a structured coalition government or a strong bipartisan system, fiscal soundness is likely to be undermined [40]. In addition, there are slight differences in operational definitions, but generally, it is argued that the higher the number of expenditure departments or the larger the size of the Cabinet, the lower the financial performance [41–44]. In addition, there is a tendency for expansion of deficit and debt when there are a large number of effective political parties in the

How Does a Welfare State achieves Fiscal Sustainability? A Study of the Impact of Tax Equity

http://dx.doi.org/10.5772/intechopen.72527

101

The ideological composition of the Cabinet was also affected. The greater the proportion of politicians supporting a left-wing ideology in the Cabinet, the greater the likelihood that the state's fiscal soundness will deteriorate [43]. Traditionally, politicians who support a leftist ideology are relatively supportive of public spending, particularly welfare spending, and have a tolerance for fiscal deficit [46, 47]. However, it is difficult to say with certainty that finances are unstable in the tradition of a representative system. This is consistent with Schmidt [48], who contended that the political composition or ideological differences of a government should not only lead to differences in financial performance, but that the political and economic conditions of each country should also be taken into account. In countries where a social democratic ideology is dominant within the Cabinet, social security spending is generally high, but the level of welfare spending and debt accumulation in these countries has not been high since mid-1970s [48]. While the left wing is generally favorable to a high tax burden and increased public spending, it is also true that differences in the composition of financial and tax systems have played a more important role than ideology in actual history [10].

As mentioned above, the influence of political formulations is limited, and studies focusing on financial systems have recently expanded. Since 1970s, OECD countries have pursued a series of reforms to effectively manage government spending growth and overcome fiscal deficits [49, 50]. In addition, it is necessary to establish a budget system for total budget allocations. In recent empirical studies, the introduction of a top-down budgeting system has had a positive effect on fiscal soundness [27]. In addition, the introduction of explicit fiscal rules has proved effective [51]. The introduction of a fiscal system that controls public expenditures and revenue levels is effective in promoting fiscal soundness, but caution is needed in interpreting it. First, the effectiveness of the fiscal system affects final fiscal performance in combination with the attributes of the political system in each country [52]. Indeed, Hallerberg et al. [32, 33] formulate a centralization index and a rule index for the political system and fiscal policy decision structures to determine their impact on the rate of change in national debt. According to their results, strong fiscal rules in a representative council system and a concentration of decisionmaking power over fiscal policy decisions in a majoritarian system or among mixed-government countries have a statistically significant effect on reducing the national debt ratio.

There are two limitations in the existing research in identifying the determinants of fiscal sustainability of the welfare state. These are further divided into two dimensions: the measure-

coalition or there is a small share of the ruling party in Parliament [43, 45].

**2.2. Limitations of existing studies and approaches of this study**

ment of dependent variables and the composition of independent variables.

In the past, inflation was the main variable of fiscal soundness [25]. Because the national debt is a nominal asset, a slight rise in prices alone can significantly lower the real value of government bonds. However, recently developed countries have guaranteed the independence of the Central Bank in order to prevent inflation risks arising from the arbitrary use of monetary policy. Thus, the importance of monetary policy and inflationary taxation on fiscal soundness has weakened [26]. Especially in the case of European Union countries, it is argued that monetary policy cannot be utilized in accordance with the reality of each country, and thus, it is further argued that there is a limit to the guarantee of financial stability [13, 26].

As confidence in monetary policy weakened following, the influence of fiscal policy began to be emphasized [26]. The most important variable is the aging population. Aging of the population leads to a reduction in the number of workers who can contribute to public finance, an increase in the burden of care, and an increase in welfare spending for the elderly. This may in turn increase the financial burden of the government and undermine financial stability. However, government spending does positively affect the sustainability of national debt, depending on the sector or the form of expenditures [20, 27]. In terms of financial revenues, Kaplanoglou and Rapanos [27] demonstrate that increasing the progressive tax burden may contribute to fiscal sustainability.


**1. Introduction**

The perovskite solar cells (PSCs) have received a lot of interest in recent years from academics due to their unique characteristics [1–3]. Although the reported power conversion efficiencies (PCEs) of PSCs have improved significantly, the perovskite community is currently placing more attention on improving device stability [4]. The high durability of carbon-based back electrodes (CPSCs) across a variety of environmental and operating situations has been noted [5,6]. It is important to note that their PCEs still fall short of those of cutting-edge PSCs that use metal-based electrodes [7].

A hybrid organic–inorganic perovskite substance called MAPbI3 is regarded as one of the most alluring options for inexpensive yet powerful absorber materials for solar energy applications [8,9]. The power conversion efficiency (PCE) of perovskite solar cells based on methylammonium lead iodide (MAPbI3) has significantly improved recently, with reported PCEs rising from 3.8% to 20.01% [10]. In a recent study, MAPbI3 was mechanically deposited onto the TiO2 layer in order to create a completely printable mesoscopic solar cell utilizing TiO2/ZrO2/Carbon (TZC) sheets [11]. Because an organic hole-transporting material (HTM) is not present, TZC-based materials offer lower material costs and better stability.

During this research, we successfully fabricated a perovskite solar cell in the laboratory under full ambient conditions using a FTO/C-TiO2/M-TiO2/ZrO2/carbon/MAPbI3 architecture. By carefully optimizing the pattern of each layer to prevent the material from overlapping, we achieved a promising power conversion efficiency (PCE) of 4.2%. Moreover, the device's performance was significantly improved to a PCE of 5.36% through humidity treatment. These findings underscore the potential of ambient air perovskite solar cells as a cost-effective and efficient approach for commercial production. The demonstrated stability and performance enhancements lay the foundation for upscaling perovskite solar cell manufacturing on an industrial level, offering a hopeful path towards sustainable and renewable energy solutions.

**Citation:** Basit, A.; Khan, A.D.; Khan, A.D. Fabrication of Carbon-Based Perovskite Solar Cell under Ambient Condition. *Eng. Proc.* **2023**, *45*, 32. https://doi.org/10.3390/ engproc2023045032

Academic Editors: Mohammad Javed Hyder, Muhammad Mahabat Khan, Muhammad Irfan and Manzar Masud

Published: 12 September 2023

#### **2. Cell Fabrication by Using Screen Printing Methodology**

The normal cleaning procedure is washing the samples with hand soap detergent, followed by 15 min of sonication in deionized (DI) water. The samples are then subjected to a 15 min sonication process with acetone, isopropyl alcohol (IPA), and acetone at a temperature of 40 ◦C. The samples are then dried with a flow of nitrogen gas after being sonicated with the abovementioned solvents, and they are then kept at room temperature for quick usage in the next phases. In the second phase, we created and deposited the perovskite solar architecture "FTO/C-TiO2/M-TiO2/ZrO2/Carbon paste/MAPbI3" using the screen printing technique, as shown in the Figure 1 [12]. To create a solar cell, several meshes are employed for various materials. The open mesh pores hold the viscous ink in place when it is applied to the screen by a squeegee. Compact TiO2 is thinly placed over a glass surface that has been coated in fluorine-doped tin oxide (FTO) to prepare the substrate. Utilising ethanol and acetone, the compact TiO2 layer's mesh structure is cleaned. The film is then given a 30 min annealing treatment at 500 ◦C to encourage crystallization. Mesoporous TiO2 (m-TiO2) is the fourth layer in the manufacturing process. This layer is essential to perovskite solar cells (PSCs) because it serves as a scaffold for perovskite crystal growth as well as being a selective contact for electron extraction. On top of the compact TiO2 (C-TiO2) layer that was previously deposited, the M-TiO2 layer is applied. Following deposition, the substrate is subjected to a 30 min annealing process at 500 ◦C to encourage the crystallization and structural stability of the M-TiO2 layer. Applying a ZrO2 paste using a screen-printing process over the TiO2 layer is the following step. After that, control cells are put through a 30 min sintering process at 400 ◦C. The carbon back electrode is placed onto the ZrO2 layer after the prior procedures. The sample is subsequently heated to 40 ◦C for 30 min to guarantee adequate bonding and structural stability. The perovskite solar cell's performance and general efficiency are improved by this technique. Using the drop casting method, the last layer of perovskite is put onto the substrate. The perovskite film is then improved by annealing it for an hour at 70 ◦C to promote further crystallization [13].

**Figure 1.** Fabrication steps of the perovskite solar cell. (**a**) c-TiO2 layer deposition on FTO Coated Glass, (**b**) m-TiO2 layer deposition on c-TiO2 layer, (**c**) ZrO2 layer deposition on m-TiO2, (**d**) carbon + Perovskite layer deposition.

#### **3. Result and Discussion**

The fabricated perovskite solar cell comprised of the FTO/C-TIO2/M-TIO2/ZrO2/carbon/ MAPbI3 architecture exhibited an initial efficiency of 4.2%. This efficient structure offered several

advantages; notably, a well-defined interface which potentially improved the charge collection and light absorption capabilities, thus leading to increased efficiency.

Post fabrication, the solar cell underwent a humidity treatment, resulting in a noticeable enhancement in the overall efficiency to 5.36%. This could be attributed to the fact that a controlled humidity environment can facilitate the crystallization of perovskite, enhancing the perovskite layer's quality and, hence, the device performance. Moreover, the induced humidity could potentially have optimized the morphology of the MAPbI3 layer, which can further contribute to efficiency enhancement. Figure 2a shows the J-V curve before and after humidity treatment of the perovskite solar cell.

**Figure 2.** (**a**) J-V curve before and after humidity treatment of perovskite solar cell, and (**b**) absorption, reflection and transmission spectra of the perovskite solar cell.

Figure 2b shows the absorption, reflection, and transmission spectra of the perovskite solar cell, in which almost 90% of the absorption was achieved in our device and only a low amount of reflection has been observed of approximately 10%. Moreover, it can be seen that nearly 0% transmission has been observed.

#### **4. Conclusions**

A highly stable 5.36% efficient solar cell is reported which can be scaled up to fabricate large-area perovskite-based solar modules. This structure utilizes the mesoporous zirconia layer, which is used as an insulation layer, as an alternative for the hole transport layer, which is highly stable. Though this layer reduces the efficiency, it is cost effective and increases the stability of the structure, thus increasing its prospects for commercialization. A dual titania layer, i.e., thin compact titania along with a mesoporous titania, is used as an electron transport layer. The structure utilizes a carbon black blend along with graphite particles as the hole selector layer, as well as cathode. Due to its hydrophobic nature, this layer provides a protective cover to perovskite crystals, thus increasing the lifetime of this solar cell. The perovskite precursor solution 5-AVA-MAPbI3 is infiltrated in the mesoporous layers. Due to the presence of aminovaleric acid along with organic cation, this perovskite is more stable compared to conventional methylammonium lead iodide crystals. Silver is used at both electrodes for charge collection due to its cost-effectiveness and efficient charge transportation. Thus, these solar cells are an excellent alternative for conventional silicon-based solar cells since these cells are cost effective and have simple fabrication processes. The screen printing technique is used for the fabrication of these solar cells, which can easily be used for layer thickness optimization and scaling up the module size. Moreover, these solar cells can be used as a basic model for the commercialization and initiation of perovskite solar manufacturing in Pakistan.

**Author Contributions:** Conceptualization, A.B.; methodology, A.B., A.D.K. (Aimal Daud Khan); fabrication, A.B., A.D.K. (Aimal Daud Khan); characterization, A.B., A.D.K. (Aimal Daud Khan); resources, A.D.K. (Adnan Daud Khan); writing—original draft preparation, A.B.; review and editing, A.D.K. (Aimal Daud Khan); supervision, A.D.K. (Adnan Daud Khan) All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

**Acknowledgments:** All authors are grateful to US-Pakistan Center for Advanced Studies in Energy, University of Engineering & Technology, Peshawar for providing the facilitation to fabricate the perovskite solar cell.

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

#### **References**


**Acknowledgements**

The authors are gratified to University of the Punjab through Punjab University Research grant/Mujtaba Ikram for fiscal year 2022-2023.

*Graphene Based Functional Hybrids: Design and Technological Applications DOI: http://dx.doi.org/10.5772/intechopen.108791*


*Article* **If You Aim Higher Than You Expect, You Could Reach Higher Than You Dream: Leadership and Employee Performance**

**Naveed Ahmad Khan 1,\*, Silke Michalk 1, Kirill Sarachuk 1 and Hafiz Ali Javed 2**

**Abstract:** Leadership is about lifting a person's vision, raising their productivity to higher standards and creating a personality beyond their usual capabilities. Our study examines the Pygmalion effect and leader-member exchange (LMX) on employee task performance via organizational commitment. The data was collected from 280 middle-level managers from top ten banks in Pakistan. This study offers three main contributions to the literature. First, our results discover a strong link between the Pygmalion effect, LMX and employees' task performance through mediation of organizational commitment. Secondly, our study indicates that leaders should have higher quality relationships with employees and higher task performance expectations. Finally, most previous studies focused on leadership approaches or have been conducted in western developed countries. To our knowledge, this study is a unique contribution to the literature on leaders' expectations in changing and diverse environments, as in underdeveloped countries like Pakistan.

**Keywords:** employee performance; leader-member exchange (LMX); leaders expectations; social exchange; commitment


**4. Measurements**

Since the risk related quantities, *e.g.* effective dose, could not be measured, some measurable quantities need to be defined. These measurable quantities should then be an estimation of the risk related quantities. As an example of the use of data from field gamma spectrometry to estimate the radiation dose, some results from repeated measurements are presented.

#### **4.1 Measurable quantities**

The relations between the different categories of quantities, risk related and measurable, are shown in Figure 12. The physical quantities, such as the absorbed dose, can be used to calculate risk related quantities by the use of weighting factors (ICRP 1991; ICRP, 2007), but also by conversion coefficients (*e.g.* ICRP, 1996). Operational quantities are derived from the physical quantities through definitions given by the ICRU (ICRU 1993; ICRU, 2001), for photon as well as for neutron irradiation. These definitions utilises the so called ICRUsphere – a tissue equivalent sphere of 30 cm diameter – and the absorbed dose at different depths in the sphere. Furthermore, relations between risk related and measurable quantities can be found from data given by the ICRP (ICRP, 1996).

Environmental Dosimetry – Measurements and Calculations 193

When the effective dose is estimated by detectors worn by individuals, special attention ought to be given to how the detector is calibrated. In these measurements the detector is often a TL-dosimeter (Thermo Luminescence Dosimetry, TLD), which is commonly used for monitoring workers at hospitals or in the nuclear industry. These detectors are calibrated to show the personal dose equivalent and if the reading is to be used for estimation of effective dose, the relation between the reading and air kerma must be known. Thereafter the

We have made repeated field gamma measurements at 34 predetermined sites in western Sweden (Almgren & Isaksson, 2009) and the results are shown here to give an example of the use of these data to estimate the ambient dose equivalent. By a proper calibration of the field gamma detector, the amount of different radioactive elements in the ground can be determined. For the naturally occurring radionuclides with an assumed homogeneous depth distribution the inventory is given as Bq kg-1. However, for 137Cs a plane source is assumed and the activity given as Bq m-2. The latter is a common procedure when the depth distribution is unknown and the reported "equivalent surface deposition" (Finck, 1992) will underestimate the true inventory due to the absorption of photons in the ground. The quantity is, however, still a good measure of the photon fluence rate above the ground. Using published dose rate conversion factors and the relation between absorbed dose and ambient dose equivalent the field gamma measurements may be compared to intensimeter measurements made in connection to the field gamma measurements. Figure 14 shows the sum of the contribution to the ambient dose equivalent from the radionuclides in the uranium series, the thorium series and 40K, as well as the contribution from 137Cs. The figure also shows the results from intensimeter measurements, corrected for the contribution from cosmic radiation. Although a correction has been made to compensate for the fact that the intensimeter is calibrated for 137Cs (0.662 MeV), whereas the mean energy of the naturally

Fig. 14. Ambient dose equivalent rate at 34 reference sites shown as the sum of the contribution from the radionuclides in the uranium series, the thorium series and 40K, as well as the contribution from 137Cs. Also shown are the results from intensimeter measurements, corrected for the contribution from cosmic radiation and photon energy

effective dose can be estimated by the relations given above.

**4.2 Measurements in western Sweden**

used in the calibration.

Fig. 12. Relations between the quantities of interest in radiation protection and measurements. Only one of the measurable and risk related quantities, respectively are shown in the figure; several other operational quantities are defined, which are used to monitor the radiation dose to individuals.

Instruments used for radiation protection purposes, *e.g.* intensimeters, are often calibrated to directly show a measurable quantity and guidelines for the calibration of those instruments have been issued by the IAEA (IAEA, 2000). Other types of detectors, *e.g.* high-purity germanium detectors (for determination of activity or fluence rate by field gamma spectrometry) or ionisation chambers (for determination of absorbed dose), can be used to measure a physical quantity. The relationship between detector response and the physical quantity of interest is then found by calibration.

Several measurable quantities have been defined for different purposes. Some are used to monitor personal exposure and others to monitor the radiation environment. The quantity of interest in environmental measurements is often the ambient dose equivalent, *H*\*(10), since it is an estimate of the effective dose. From Figure 13 it is obvious that an instrument calibrated to show ambient dose equivalent should never underestimate the effective dose. This may cause deviations if effective dose is estimated from field gamma spectrometry and compared to the reading of an intensimeter calibrated to show ambient dose equivalent.

Fig. 13. Effective dose and ambient dose equivalent per unit air kerma, respectively. Data from ICRP (1996).

When the effective dose is estimated by detectors worn by individuals, special attention ought to be given to how the detector is calibrated. In these measurements the detector is often a TL-dosimeter (Thermo Luminescence Dosimetry, TLD), which is commonly used for monitoring workers at hospitals or in the nuclear industry. These detectors are calibrated to show the personal dose equivalent and if the reading is to be used for estimation of effective dose, the relation between the reading and air kerma must be known. Thereafter the effective dose can be estimated by the relations given above.

#### **4.2 Measurements in western Sweden**

192 Radioisotopes – Applications in Physical Sciences

Fig. 12. Relations between the quantities of interest in radiation protection and

reading of an intensimeter calibrated to show ambient dose equivalent.

monitor the radiation dose to individuals.

quantity of interest is then found by calibration.

from ICRP (1996).

measurements. Only one of the measurable and risk related quantities, respectively are shown in the figure; several other operational quantities are defined, which are used to

Instruments used for radiation protection purposes, *e.g.* intensimeters, are often calibrated to directly show a measurable quantity and guidelines for the calibration of those instruments have been issued by the IAEA (IAEA, 2000). Other types of detectors, *e.g.* high-purity germanium detectors (for determination of activity or fluence rate by field gamma spectrometry) or ionisation chambers (for determination of absorbed dose), can be used to measure a physical quantity. The relationship between detector response and the physical

Several measurable quantities have been defined for different purposes. Some are used to monitor personal exposure and others to monitor the radiation environment. The quantity of interest in environmental measurements is often the ambient dose equivalent, *H*\*(10), since it is an estimate of the effective dose. From Figure 13 it is obvious that an instrument calibrated to show ambient dose equivalent should never underestimate the effective dose. This may cause deviations if effective dose is estimated from field gamma spectrometry and compared to the

Fig. 13. Effective dose and ambient dose equivalent per unit air kerma, respectively. Data

We have made repeated field gamma measurements at 34 predetermined sites in western Sweden (Almgren & Isaksson, 2009) and the results are shown here to give an example of the use of these data to estimate the ambient dose equivalent. By a proper calibration of the field gamma detector, the amount of different radioactive elements in the ground can be determined. For the naturally occurring radionuclides with an assumed homogeneous depth distribution the inventory is given as Bq kg-1. However, for 137Cs a plane source is assumed and the activity given as Bq m-2. The latter is a common procedure when the depth distribution is unknown and the reported "equivalent surface deposition" (Finck, 1992) will underestimate the true inventory due to the absorption of photons in the ground. The quantity is, however, still a good measure of the photon fluence rate above the ground.

Using published dose rate conversion factors and the relation between absorbed dose and ambient dose equivalent the field gamma measurements may be compared to intensimeter measurements made in connection to the field gamma measurements. Figure 14 shows the sum of the contribution to the ambient dose equivalent from the radionuclides in the uranium series, the thorium series and 40K, as well as the contribution from 137Cs. The figure also shows the results from intensimeter measurements, corrected for the contribution from cosmic radiation. Although a correction has been made to compensate for the fact that the intensimeter is calibrated for 137Cs (0.662 MeV), whereas the mean energy of the naturally

Fig. 14. Ambient dose equivalent rate at 34 reference sites shown as the sum of the contribution from the radionuclides in the uranium series, the thorium series and 40K, as well as the contribution from 137Cs. Also shown are the results from intensimeter measurements, corrected for the contribution from cosmic radiation and photon energy used in the calibration.

Environmental Dosimetry – Measurements and Calculations 195

Clouvas, A.; Xanthos, S.; Antonopoulos-Domis, M. & Silva, J. (2000). Monte Carlo

Finck, R R. (1992). *High resolution field gamma spectrometry and its application to problems in*

Golikov, V. ; Wallström, E. ; Wöhni, T. ; Tanaka, K. ; Endo, S. & Hoshi, M. (2007). Evaluation

International Commission on Radiation Units and Measurements (1993). *Quantities and*

International Commission on Radiation Units and Measurements (1998). *Fundamental*

International Commission on Radiation Units and Measurements (2001). *Determination of*

International Commission on Radiological Protection (1977). *Recommendations of the*

International Commission on Radiological Protection (1991). *1990 Recommendations of the*

International Commission on Radiological Protection (1996). *Conversion coefficients for use in*

International Commission on Radiological Protection (2007). *The 2007 Recommendations of the*

International Atomic Energy Agency (2000). *Calibration of Radiation Protection Monitoring*

Jacob, P.; Paretzke, H G.; Rosenbaum, H. & Zankl, M. (1988). Organ Doses from

Jacobi, W. (1975). The Concept of the Effective Dose - A Proposal for the Combination of

McParland, B J. (2010). *Nuclear medicine radiation dosimetry*, ISBN 978-1-84882-125-5,

Ninkovic, M M.; Raicevic, J J. & Adrovic, F. (2005). Air Kerma Rate Constants for Gamma

Shultis, J K & Faw, R E. (2000). *Radiation Shielding*, ISBN 0-89448-456-7, American Nuclear

Organ Doses, *Rad. and Environm. Biophys*. Vol.12, pp.101-109.

Emitters in Soil, *Health Physics*, Vol.78, No.3, pp.295-302.

*environmental biophysics*, Vol.46, pp.375-382.

Physics, Malmö, Sweden.

Bethesda, USA

Bethesda, USA

21 (1–3).

(3/4).

37 (2-4)

Publications, Bethesda, USA

Vol.54, No.6, pp. 617-633.

Springer-Verlag London, GB.

Society, La Grange Park, IL, USA.

4, pp. 247–250.

the ICRP l(3). Pergamon Press, Oxford.

*Instruments*, IAEA Safety Reports Series No.16.

Calculation of Dose Rate Conversion Factors for External Exposure to Photon

*environmental radiology*. Thesis. University of Lund, Department of Radiation

of conversion coefficients from measurable to risk quantities for external exposure over contaminated soil by use of physical human phantoms, *Radiation and*

*Units in Radiation Protection Dosimetry,* ICRU Publications 51, ICRU Publications,

*Quantities and Units for Ionizing Radiation,* ICRU Publications 60 ,ICRU Publications,

*Operational Dose Equivalent Quantities for Neutrons,* ICRU Publications 66, ICRU

*International Commission on Radiologicul Protection*. ICRP Publication 26. Annuals of

*International Commission on Radiological Protection*. ICRP Publication 60. Ann. ICRP

*radiological protection against external radiation*. ICRP Publication 74. Ann. ICRP 26

*International Commission on Radiological Protection*, ICRP Publication 103, Ann. ICRP

Radionuclides on the Ground. Part I. Simple Time Dependencies, *Health Physics*.

Emitters used most often in Practice, *Radiation Protection Dosimetry*, Vol.115, No.1–

occurring radionuclides are slightly higher, a deviation between the results remains. One explanation may be that the measured area differs due to different angular sensitivity of the two measurements systems and that the correction of the intensimeter reading is insufficient. Still there is a good agreement between the two methods to estimate the ambient dose equivalent.

Figure 15 shows the contribution from each of the terms in the sum depicted in Figure 14. The main contributor to the ambient dose equivalent is 40K and the contribution from 137Cs is practically negligible in this area.

Fig. 15. Ambient dose equivalent rate at 34 reference sites from the radionuclides in the uranium series, the thorium series and 40K, as well as from 137Cs.

#### **5. Conclusion**

This chapter includes the basic relations for calculating the primary photon fluence rate from environmental sources of different shapes. Such calculations may be used for calibrating field equipment and also for estimating the exposure to people in the vicinity of the source. The chapter also dealt with practical environmental measurements and the importance to keep in mind the relation between effective dose and ambient dose equivalent. Measurements made by intensimeters tend to overestimate the effective dose due to the calibration requirements.

#### **6. References**

occurring radionuclides are slightly higher, a deviation between the results remains. One explanation may be that the measured area differs due to different angular sensitivity of the two measurements systems and that the correction of the intensimeter reading is insufficient. Still there is a good agreement between the two methods to estimate the

Figure 15 shows the contribution from each of the terms in the sum depicted in Figure 14. The main contributor to the ambient dose equivalent is 40K and the contribution from 137Cs

Fig. 15. Ambient dose equivalent rate at 34 reference sites from the radionuclides in the

This chapter includes the basic relations for calculating the primary photon fluence rate from environmental sources of different shapes. Such calculations may be used for calibrating field equipment and also for estimating the exposure to people in the vicinity of the source. The chapter also dealt with practical environmental measurements and the importance to keep in mind the relation between effective dose and ambient dose equivalent. Measurements made by intensimeters tend to overestimate the effective dose

Almgren, S. & Isaksson, M. (2009). Long-term investigation of anthropogenic and naturally

Attix, F H. (1991). *Introduction to radiological physics and radiation dosimetry*, ISBN<PHONE_NUMBER>,

occurring radionuclides at reference sites in western Sweden, *Journal of*

uranium series, the thorium series and 40K, as well as from 137Cs.

*Environmental Radioactivity*, Vol.100, pp.599-604.

Wiley-VCH Verlag GmbH, Germany.

ambient dose equivalent.

**5. Conclusion**

**6. References**

due to the calibration requirements.

is practically negligible in this area.

*Departamento de Física, Facultad de Ciencias Exactas, Universidad Nacional de La Plata*

When the Earth was formed, the crust and consequently the soil and water were conformed by a wide variety of chemical elements with different concentrations; being some of these radioactives. There are different activity levels of natural radionuclides, as those of the 238U and 232Th decay chains, 40K, 7Be and 14C, etc. along the planet [Cooper et al., 2003]. Among the 80 nuclides found in the environment, the more relevant concerning the radiobiological significance are 40K, and the nuclides belonging to the 238U and 232Th decay chains. The human activities can strongly modify the natural concentrations due to the presence of residues or accumulation of elements caused by the release of effluents to the environment. In the 60´s the nuclear power production and nuclear weapon testing discharge to the environment anthropogenic nuclides. In particular, the Southern Hemisphere was mainly polluted by the debris originated in the South Pacific and middle Atlantic nuclear weapon tests [UNSCEAR, 2008]. Along with the class of anthropogenic gamma emitter nuclides releases, the 137Cs is the most prominent isotope in the Earth crust originated by fission process. It is considered as one of the hazardous environmental contaminant due to the contribution to the external irradiation exposure and its incorporation to the human food

Regardless, both natural and man-made nuclides have radiobiological implication because they significantly contribute to human external radiation dose and to the internal dose by inhalation and ingestion [Cooper et al., 2003; UNSCEAR, 2008]. The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) has estimated that exposure to natural sources is approximately 98% of the total radiation dose (excluding medical exposure) [UNSCEAR, 2000; UNSCEAR, 2008]. The dose arising from natural nuclides varies worldwide depending upon factors such as height above sea level, the amount and type of radionuclides in the air, food and water, as well as the concentration of the natural nuclides in the soil and rocks, which in turn depend on the local geology of each

The information about the presence and migration anthropogenic radionuclides is crucial to fully understand the long-term behaviour in the environment, the uptake by flora and fauna including the human food chain, as well as potential contribution to groundwater. In consequence, before assessing the radiation dose to the population, a precise knowledge of the activity of a number of radionuclides is required [UNSCEAR, 2000;

**1. Introduction**

chain [Singh et al., 2009].

region, etc.

María Luciana Montes and Judith Desimoni

 *Instituto de Física La Plata – CONICET,*

*Argentina*

United Nations Scientific Committee on the Effects of Atomic Radiation. (2008). *UNSCEAR 2008 Report to the General Assembly, with scientific annexes. Annex B.* **11**

María Luciana Montes and Judith Desimoni

*Departamento de Física, Facultad de Ciencias Exactas, Universidad Nacional de La Plata Instituto de Física La Plata – CONICET, Argentina*

### **1. Introduction**

196 Radioisotopes – Applications in Physical Sciences

United Nations Scientific Committee on the Effects of Atomic Radiation. (2008). *UNSCEAR*

When the Earth was formed, the crust and consequently the soil and water were conformed by a wide variety of chemical elements with different concentrations; being some of these radioactives. There are different activity levels of natural radionuclides, as those of the 238U and 232Th decay chains, 40K, 7Be and 14C, etc. along the planet [Cooper et al., 2003]. Among the 80 nuclides found in the environment, the more relevant concerning the radiobiological significance are 40K, and the nuclides belonging to the 238U and 232Th decay chains. The human activities can strongly modify the natural concentrations due to the presence of residues or accumulation of elements caused by the release of effluents to the environment. In the 60´s the nuclear power production and nuclear weapon testing discharge to the environment anthropogenic nuclides. In particular, the Southern Hemisphere was mainly polluted by the debris originated in the South Pacific and middle Atlantic nuclear weapon tests [UNSCEAR, 2008]. Along with the class of anthropogenic gamma emitter nuclides releases, the 137Cs is the most prominent isotope in the Earth crust originated by fission process. It is considered as one of the hazardous environmental contaminant due to the contribution to the external irradiation exposure and its incorporation to the human food chain [Singh et al., 2009].

Regardless, both natural and man-made nuclides have radiobiological implication because they significantly contribute to human external radiation dose and to the internal dose by inhalation and ingestion [Cooper et al., 2003; UNSCEAR, 2008]. The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) has estimated that exposure to natural sources is approximately 98% of the total radiation dose (excluding medical exposure) [UNSCEAR, 2000; UNSCEAR, 2008]. The dose arising from natural nuclides varies worldwide depending upon factors such as height above sea level, the amount and type of radionuclides in the air, food and water, as well as the concentration of the natural nuclides in the soil and rocks, which in turn depend on the local geology of each region, etc.

The information about the presence and migration anthropogenic radionuclides is crucial to fully understand the long-term behaviour in the environment, the uptake by flora and fauna including the human food chain, as well as potential contribution to groundwater. In consequence, before assessing the radiation dose to the population, a precise knowledge of the activity of a number of radionuclides is required [UNSCEAR, 2000;

underground essays were the more numerous; however, the global environmental impact resulted small because the radioactive material remains in the essay area. On the contrary, the atmospheric ones delivered to the atmosphere huge amounts of radioactive detritus causing a big impact on the environment [UNSCEAR, 2008; Valkovic, 2000]. It is worth to mention that because of the atmospheric circulation, approximately the 82 % of the debris remain in the hemisphere of injection [UNSCEAR, 2008; Valkovic, 2000]. The relevant nuclides originate in the essays were 3H, 14C, 54Mn, 55Fe, 85Kr, 89Sr, 90Sr, 95Zr, 103Ru, 106Ru, 131I, 137Cs, 131Ce and 144Ce, among others [UNSCEAR, 1982]. Due to 90Sr and 137Cs are volatiles and have large half-life (28.6 years and 30.2 years, respectively) they are dispersed in the atmosphere, comprising the

When analyzing the total annual effective dose received by human from natural sources, the dose received by the cosmic ray, terrestrial exposure, ingestion and inhalation of long-lived natural radionuclides needs consideration. Each environmental matrix, e.g. soil, air and water, has several associated pathways. These three environmental media cannot be thought as isolated and so, nuclide transfers are produced from one to the other. The different pathways exposure routes are schematized in the Fig. 1. The importance of these paths depends upon the particular radionuclide or radionuclides present in each compartment. The starting point to evaluate the people doses is to determine the nuclide concentrations in the environmental matrixes [USNCEAR, 2000;

stratospheric global fallout, contributing to the residual background.

Fig. 1. Schematic terrestrial pathways of nuclide transfers and dose to humans.

Two kinds of surveys have been performed, some of them deal with the determination of nuclide activity concentrations in depth, while others only reported single values of surface activity concentrations. Argentina, Brazil and Chile are the most studied countries, while there are reported a few data of Venezuela and Uruguay. The location of the monitored places, type of survey and monitored nuclides are summarized in the Table 1. Regarding the natural nuclides in South America, the reports of UNSCEAR only account values of the activity concentration of the natural nuclide 40K for Argentina [UNSCEAR, 2000; UNSCEAR, 2008]. In San Luis Province, Argentina, two sites have been studied [Juri Ayub et al., 2008]. Recently, the first systematic studies to establish baseline activities for the naturally occurring radionuclides in unperturbed soils around La Plata city, Province of Buenos Aires, have been settled on samples taken from the surface down to a depth of 50 cm [Montes et al. 2010a, 2010b]. Moreover, in four superficial soils in the Ezeiza region, Argentina, the

UNSCEAR, 2008].

**3. Monitored regions and dataset**

UNSCEAR, 2008]. The mobility of the radionuclide in the ecosystem involves a number of complex mechanisms [Velasco et al., 2006; IAEA, 2010; Salbu, 2009; Cooper et al., 2003; Sawhney, 1972; Cornell, 1993; Staunton et al. , 2002; Bellenguer et al., 2008], and their transfer through the environmental compartments implies multiple interactions between the biotic and abiotic components of the ecosystem, as well as human interferences like the use of fertilizer [Tomazini da Conceic & Bonotto, 2006] or the overexploitation of the natural resources. For the identification of these interactions it is necessary to develop and test predictive models describing the radionuclide fluxes from the environment to the man.

In South America, the soil resource is extensively used in agriculture, stockbreeding and for building materials. Baselines of natural and anthropogenic activity nuclides in several countries are not established ye, as well regulations concerning the natural and anthropogenic activity and chemical restrictions in freshwater and food accordingly to the local situations. These facts and the scattered of the activity dataset put in relevance the present review on nuclide activity determinations in soils of South America, that could be considered as the first attempt in this direction.

A systematic compilation of radionuclide activity data of soil of Argentina, Brazil, Chile, Venezuela and Uruguay are presented. Radionuclide activity data concern to the natural 40K, 238U, and 232Th and to the anthropogenic 137Cs nuclides. These different pieces of information are put together, the quality of the environmental compartments is provided and the impact on the population is evaluated throughout the exposure dose. The migration of 137Cs in soil is also analysed in the frame of different approaches [Kirchner, 1998; Schuller et al., 1997], and the transport parameters are discussed. Moreover, the caesium inventories are compared with the latitudinal UNSCEAR predictions [UNSCEAR 2000, UNSCEAR 2008].


**SONOGRAPHY**

Edited by **Kerry Thoirs**

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http://dx.doi.org/10.5772/1403 Edited by Kerry Thoirs

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Ali Pourmand, Hamid Shokoohi, Keith Boniface, Rahul Khosla, Roy Moncayo, Helga Moncayo, Bing Xu, Jo Kitawaki, Yuying Duan, Jilian Ding, Chee Wai Mak, Wen Sheng Tzeng, Guang-Huan Sun, Shou-Hung Tang, Tai-Lung Cha, Hajime Kataoka, Olivier Walusinski, Fabrice Vuillier, Laurent Tatu, Paola Montiel, Françoise Cattin, Thierry Moulin, Ragab Hani Donkol, Ahmad Al Nammi, Hung-Chang Lee, Chuen-Bin Jiang, Chun-Yan Yeung, Wai-Tao Chan, Juan Carlos Bello-Munoz, Lluis Cabero, Elena Carreras, Alexandra Casasbuenas, Paula Oliveros, Nazareth Campo, Silvia Arévalo, Mauricio Ayala, Heino Hille, Madeleine Shanahan, David Washburn, Natasha Schultz, Holly Phillips, Thomas Manfred Scholbach, Alain Saraux, Thierry Marhadour, Felix Schlachetzki, Maria-Andreea Gamulescu, Michael Ertl, Kerry Thoirs

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