3.2.5. Test Site GPP without LSWI

In this experiment, all LSWI data were deleted from the training data, which were then trained for each site flux. The final prediction results are shown in Figure 13. Compared to the prediction results without any feature ablation of the training data, the prediction accuracy of the AR site improves significantly and is only lower than that after removing NDVI. The DXST, DXSW, NMC, and ZF sites have similar prediction accuracy as in the previous ablation experiments, with a large decrease in accuracy, and the prediction accuracy of the ZF site is only higher than that after removing EVI. The GL site shows a slight decrease in accuracy, while the HBKO, HBSH, and HBSW sites show no obvious changes in prediction accuracy.

#### 3.2.6. Summary of Factor Ablation Experiments

To observe the influence of different features on the prediction accuracy of each site more intuitively, we summarized all the feature ablation experiment results, as shown in Table 5.

**Figure 13.** Predicted GPP vs. labeled GPP at a single site (no LSWI).

Numbers in red indicate that the prediction results for the corresponding site have increased in accuracy compared to the previous results without setting a distance range; numbers in blue indicate that the results have decreased in accuracy; and numbers in black indicate that the results have no significant changes.

Table 5 indicates that removing any feature from the AR site would result in a significant improvement in accuracy, with the largest improvement obtained after removing NDVI. The removal of any feature for the DXST, DXSW, and ZF sites would lead to a degradation of accuracy, with the DXST site showing a large accuracy decline and the

lowest accuracy after removing LSWI. The DXSW site also shows a decline in accuracy, although it is smaller than that of the DXST site. The ZF site has a noticeable decline in accuracy after removing EVI. The NMC site has an abnormal increase in accuracy after removing NDVI and a decline after removing other features except NDVI. The GL site is insensitive to the removal of Ta or NDVI and shows slight decreases in accuracy after removing other features in addition to Ta and NDVI. The HBKO, HBSH, and HBSW sites are insensitive to the removal of any feature and have no obvious changes in accuracy.

#### **4. Conclusions**

In this work, we used satellite remote sensing data and flux site observation data to introduce the GeoMAN model based on an encoder–decoder framework with an attention mechanism for site features, and we obtained good results. According to the experiments on training data selection based on distance and vegetation type, we found that both distance and vegetation type had an impact on GPP prediction results, with vegetation type having a larger impact. Through the feature ablation experiments, we found that different sites showed sensitivity to different factors, with the site located in the alpine swamp meadow being insensitive to changes in environmental factors, while the site located in the alpine meadow steppe showed a different trend since the GPP prediction accuracy decreased sharply with the changes in environmental factors. The GPP prediction accuracy of the site located in the alpine Kobresia meadow also varied with environmental factor changes but was more stable than the other sites. The results of this work show that deep learning models have high accuracy when simulating site-scale GPP and, to some extent, reflect the correlation between a target site's GPP and other sites' distances, vegetation types, and meteorological factors. Our work could be used in the prediction of other factors, for example, AGB (Above Ground Biomass) and RE (Ecosystem Respiration). However, this work has some limitations. Firstly, we do not consider some factors that have an influence on productivity in Tibetan grasslands, such as soil development and drought regimes. Secondly, the data we used in this work only cover a partial area of the Tibetan Plateau region, and this introduces constraints to regional GPP assessment. In our future work, we will add more factors to the training data, for example, soil pH, soil fertility, and soil organic matter (SOM), since high soil pH and a lack of soil fertility limit plant productivity [36], and SOM is able to enhance alpine grassland productivity by improving the soil structure, aggregates, and cation-exchange capacity (CEC) under high aridity conditions [37]. Moreover, ecological factors, such as growing and non-growing seasons, will be considered, and larger regional-scale data will be used in future training and learning processes. These improvements will help us perform more accurate and larger-scale GPP simulations.

**Author Contributions:** Conceptualization, Q.Y. and Y.W.; methodology, Q.Y. and N.N.; software, Q.Y.; validation, Q.Y., Z.W. and M.W.; formal analysis, R.C.; investigation, Q.Y.; resources, X.R.; data curation, Q.Y. and X.W.; writing—original draft preparation, Q.Y.; writing—review and editing, N.N. and X.W.; visualization, Q.Y. and W.L.; supervision, Y.W.; project administration, Q.Y.; funding acquisition, N.N. and Y.W. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the National Key Research and Development Program of China (Grant No. 2021YFF0703902).

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

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

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


*Article* **Development of Water Retentive and Thermal Resistant Cement Concrete and Cooling Effects Evaluation**

**Xiaowei Wang 1,\*, Xinyu Hu 2 , Xiaoping Ji 2 , Bo Chen 3 and Hongqing Chen 4**

**Abstract:** The high pavement temperature plays an important role in the development of urban heat island (UHI) in summer. The objective of this study was to develop water retentive and thermal resistant cement concrete (WTCC) to enhance the pavement cooling effects. The WTCC was prepared by combining a water retentive material and a high aluminum refractory aggregate (RA) with porous cement concrete (PCC). Water retention capacity test, fluidity test, and compressive strength test were used to determine the composition ratio of the water retentive material. Mechanical performance and cooling effects of WTCC were evaluated by compressive and flexural strength tests and temperature monitoring test. The mass ratios of fly ash, silica fume, cement, and water in the water retentive material were determined as 65:35:15:63.9. The compressive strength and the flexural strength of WTCC after 28 days curing were 30.4 MPa and 4.6 MPa, respectively. Compared with stone mastic asphalt (SMA) mixture, PCC, and water retentive cement concrete (WCC), surface temperature of WTCC decreased by 11.4 ◦C, 5.5 ◦C, and 4.1 ◦C, respectively, and the internal temperatures of WTCC decreased by 10.3 ◦C, 6.1 ◦C, and 4.6 ◦C, respectively. The water retentive material has benefits of strength improvements and temperature reduction for WTCC. Based on the results, WTCC proved to have superior cooling effects and the potential to efficiently mitigate the UHI effects and be used in medium traffic roads.

**Keywords:** urban heat island effects; water retentive material; water retentive and thermal resistant cement concrete; pavement temperature reduction

## **1. Introduction**

With global warming and fast urbanization, temperatures in metropolitan areas are significantly greater than the surrounding suburban areas in summer, and this phenomenon is named urban heat island (UHI) [1,2]. Studies demonstrated that pavement contributes highly to the development of UHI because the pavement temperature is very high in summer, and the pavement area percentage in urban areas may be up to 40% [3–5]. Especially, asphalt pavements have a more significant influence on the UHI effects because the heat absorptivity and the temperature of asphalt pavement are higher than other pavements [6]. The high temperature not only causes pavement distress [7] but also aggravates the UHI effects [1,8]. Therefore, developing new pavement technologies to reduce the pavement temperature has a great significance for pavement durability and sustainability of the environment.

There are mainly four ways to reduce the pavement temperature: (a) increasing the albedo of pavement surface; (b) decreasing the thermal conductivity of pavement materials; (c) utilizing water retentive pavements; and (d) using phase change materials. Increasing the albedo of pavement, known as reflective pavement, has been used for a long time to

**Citation:** Wang, X.; Hu, X.; Ji, X.; Chen, B.; Chen, H. Development of Water Retentive and Thermal Resistant Cement Concrete and Cooling Effects Evaluation. *Materials* **2021**, *14*, 6141. https://doi.org/ 10.3390/ma14206141

Academic Editors: Markus Oeser, Michael Wistuba, Pengfei Liu and Di Wang

Received: 28 September 2021 Accepted: 14 October 2021 Published: 16 October 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/).

reduce the pavement temperature [1,9]. In the eastern San Francisco Bay Area of California, the albedo and the temperature of different asphalt pavements were measured. Results indicated that the temperature and the albedos correlated well with each other. The albedo of chip-seal was about 70% of the aggregates, resulting in a surface temperature reduction of about 9.0 K compared with the traditional asphalt pavements [10]. Furthermore, coloring additives together with proper aggregates were used to increase the albedo of the pavements, and surface temperature decreased about 12 K compared to weathered asphalt [11]. In general, reflective pavements are mainly carried out using the following strategies: (a) use of white high reflective paints on the surface of the pavement [11,12]; (b) use of infrared reflective colored paints on the surface of the pavement [3,13]; (c) use of heat reflecting paints to cover aggregates [9]; and (d) use of color changing paints on the surface of the pavement [14]. The durability of the reflective pavements is the main concern in the practices.

Apart from the reflective pavements, permeable pavements and thermal resistant pavements are other pavement technologies available to reduce the pavement temperature through decreasing the thermal conductivity of pavement materials. The permeable pavements are paved by porous cement concrete or porous asphalt mixtures, which have a high air void (AV) content and lower thermal conductivity than traditional dense-graded asphalt mixtures [15,16]. Studies reported that the insulation properties of permeable pavements contributed to a temperature reduction [17,18]. Alternative aggregates with a lower thermal conductivity incorporated into asphalt mixtures have been applied to reduce pavement temperature. The thermal conductivity of ceramic, floating beads, and refractory gravel is lower than ordinary aggregates. Pavement temperature reduction was observed when the ordinary aggregates were substituted by these lower thermal conductivity aggregates [2,6]. In addition, water retentive pavements were used to decrease the pavement temperature by dissipating the heat through water evaporation [8]. Water absorption capability and water retention capacity of sintered ceramic pervious brick (CB), pervious concrete brick (PB), and open-graded pervious concrete (PC) were investigated. Results revealed that CB and PB could reduce the surface temperature by up to 20 ◦C and 12 ◦C with cooling periods of 16 h and 12 h, respectively [19]. To extend the evaporative cooling period of water retentive pavements, water retentive materials that use highly absorptive filler, such as sepiolite, fly ash, or blast furnace slag, were added into the pore structures of pervious pavements [5,20,21]. Super absorbent polymer (SAP) was added into porous asphalt mixtures, showing a significant cooling effect [22]. Recently, phase change materials incorporated with a lightweight aggregate were used in asphalt mixtures to reduce pavement surface temperature [23,24]. Surface temperature decreased about 4 ◦C under a test temperature range between 30 ◦C and 60 ◦C [24]. The phase change materials also were used in a cement mortar to accumulate heat [25].

In this study, a water retentive material was designed and combined with a thermal resistant aggregate and porous cement concrete (PCC) to develop a water retentive and thermal resistant cement concrete (WTCC). With lower thermal conductivity PCC and water evaporation of a water retentive material, the WTCC may have the potential to enhance the pavement cooling effects. The mechanical performance and the cooling effects of WTCC were also evaluated and compared with stone mastic asphalt mixtures (SMA), PCC, and water retentive cement concrete (WCC). The schematic development of WTCC and the test program is shown in Figure 1.

**Figure 1.** Schematic development of WTCC and test program. **Figure 1.** Schematic development of WTCC and test program.

#### **2. Materials and Sample Preparation 2. Materials and Sample Preparation**

The main raw materials for preparing WTCC included thermal resistant aggregate, cement, silica fume, fly ash, and water. In addition, SMA, PCC, and WCC were also prepared and compared with WTCC. A summary of the main composition of these mixtures is shown in Table 1. A water retentive material was designed for preparing the WCC and the WTCC. The main raw materials for preparing WTCC included thermal resistant aggregate, cement, silica fume, fly ash, and water. In addition, SMA, PCC, and WCC were also prepared and compared with WTCC. A summary of the main composition of these mixtures is shown in Table 1. A water retentive material was designed for preparing the WCC and the WTCC.

**Table 1.** Brief of the composition of different mixtures. **Table 1.** Brief of the composition of different mixtures.

graded 42.5 was used for PCC, WCC, and WTCC. The properties of SBS modified asphalt and cement are listed in Tables 2 and 3, respectively. Two types of coarse aggregates—serpentinite aggregate (SA) and thermal resistant aggregate of high aluminum refractory aggregate (RA)—were used, and the properties of the coarse aggregates are summarized in Table 4. SA with different sizes was used for SMA, PCC, and WCC, while RA with a uniform size of 5–10mm was used for WTCC. RA was produced by Xi'an Hua Rong Refractories CO., Ltd. The thermal conductivity of RA was 0.5 W·(m·K)−1, which is significantly lower than the ordinary aggregates of SA. **Table 2.** Properties of SBS modified asphalt. Styrene-butadiene-styrene (SBS) modified asphalt was used for SMA, while cement graded 42.5 was used for PCC, WCC, and WTCC. The properties of SBS modified asphalt and cement are listed in Tables 2 and 3, respectively. Two types of coarse aggregates serpentinite aggregate (SA) and thermal resistant aggregate of high aluminum refractory aggregate (RA)—were used, and the properties of the coarse aggregates are summarized in Table 4. SA with different sizes was used for SMA, PCC, and WCC, while RA with a uniform size of 5–10 mm was used for WTCC. RA was produced by Xi'an Hua Rong Refractories Co., Ltd. The thermal conductivity of RA was 0.5 W·(m·K)−1 , which is significantly lower than the ordinary aggregates of SA.

**Properties Value Table 2.** Properties of SBS modified asphalt.

#### **Table 3.** Properties of cement.

**Table 4.** Properties of coarse aggregates.

## *2.1. Water Retentive Material*

Water retentive material was designed to improve the absorption and the retention capacities of WCC and WTCC. The water retentive material was composed of fly ash, cement, and silica fume. Fly ash is a porous material with strong water absorption and retention capacity. Silica fume is a non-crystalline polymorph spherical particle with smooth surface, large specific surface area, and high activity. In the water retentive material, silica fume mainly acted as a lubricant to improve the fluidity, and cement provided the strength. The chemical compositions of fly ash and silica fume are shown in Table 5.

**Table 5.** Chemical compositions of fly ash and silica fume.

To prepare the water retentive material, first, cement, fly ash, and silica fume were weighted according to the composition ratio. Next, all the materials were mixed together with water, and the mixture was stirred until uniform consistency slurry was formed. The water retentive material should have good workability in order to easily infiltrate the pore structure of PCC as well as good water retention capacity to store water. The composition ratio of the water retentive material was determined based on water retention capacity (WR), fluidity (FL), and compressive strength and is discussed in the following section.

#### *2.2. Stone Mastic Asphalt (SMA)*

SMA with a nominal maximum aggregate size (NMAS) of 13.2 mm (SMA-13) was investigated and used as the surface layer of SMA pavements. SMA-13 was designed based on the Marshall mixture design method [26]. The asphalt content was 6.1%, and the AV

content was 3.5%. The gradation of SMA-13 is shown in Figure 2. A rolling compaction machine was used to prepare the specimen with a length of 300 mm, a width of 300 mm, and a height of 50 mm. Another dense graded asphalt mixture with a NMAS of 19 mm (AC-20) was compacted with the same dimensions. AC-20 was the bottom layer of SMA pavement. The SMA-13 specimen was bonded with the AC-20 specimen using emulsified asphalt to simulate the SMA pavement structure. Thus, the total height of the SMA specimen was 100 mm. the AV content was 3.5%. The gradation of SMA-13 is shown in Figure 2. A rolling compaction machine was used to prepare the specimen with a length of 300 mm, a width of 300 mm, and a height of 50 mm. Another dense graded asphalt mixture with a NMAS of 19 mm (AC-20) was compacted with the same dimensions. AC-20 was the bottom layer of SMA pavement. The SMA-13 specimen was bonded with the AC-20 specimen using emulsified asphalt to simulate the SMA pavement structure. Thus, the total height of the SMA specimen was 100 mm.

SMA with a nominal maximum aggregate size (NMAS) of 13.2 mm (SMA-13) was investigated and used as the surface layer of SMA pavements. SMA-13 was designed based on the Marshall mixture design method [26]. The asphalt content was 6.1%, and

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*2.2. Stone Mastic Asphalt (SMA)*

**Figure 2.** Gradation of SMA-13. **Figure 2.** Gradation of SMA-13.

#### *2.3. Porous Cement Concrete (PCC) 2.3. Porous Cement Concrete (PCC)*

PCC is the matrix for preparing WCC and WTCC and providing strength for them. Two types of PCC were prepared in this study. One was PCC prepared by SA (PCC-SA), and the other was PCC prepared by RA (PCC-RA). WCC was prepared by pouring the water retentive material into PCC-SA, and WTCC was prepared by pouring the water retentive material into PCC-RA. PCC-SA and PCC-RA were designed based on target valid interconnected AV content (AVvalid), workability, and flexural strength. The target AVvalid of the PCC was 18–22%, and the AVvalid was calculated based on the Equation (1). The specimens used in the AVvalid measurement were cubic specimens with lengths, widths, and heights of 150 mm after 7 days of curing. The compositions of the PCC-SA and the PCC-RA are shown in Table 6. PCC is the matrix for preparing WCC and WTCC and providing strength for them. Two types of PCC were prepared in this study. One was PCC prepared by SA (PCC-SA), and the other was PCC prepared by RA (PCC-RA). WCC was prepared by pouring the water retentive material into PCC-SA, and WTCC was prepared by pouring the water retentive material into PCC-RA. PCC-SA and PCC-RA were designed based on target valid interconnected AV content (AVvalid), workability, and flexural strength. The target AVvalid of the PCC was 18–22%, and the AVvalid was calculated based on the Equation (1). The specimens used in the AVvalid measurement were cubic specimens with lengths, widths, and heights of 150 mm after 7 days of curing. The compositions of the PCC-SA and the PCC-RA are shown in Table 6.

$$\text{AV}\_{\text{valid}} = (1 - \frac{\mathbf{m}\_{\text{water}} - \mathbf{m}\_{\text{dry}}}{\mathbf{V} \cdot \rho\_{\text{w}}}) \times 100\% \tag{1}$$

w

where mwater is saturated specimen mass in water, g; mdry is mass of specimen in air, g; V is the volume of specimens, cm3; and ρw is density of water, g/cm3. where mwater is saturated specimen mass in water, g; mdry is mass of specimen in air, g; V is the volume of specimens, cm3 ; and ρw is density of water, g/cm3 .

**Table 6.** Compositions of PCC-SA and PCC-RA. **Table 6.** Compositions of PCC-SA and PCC-RA.

#### **3. Test Methods 3. Test Methods**

Water retention capacity test, fluidity test, and compressive strength test were used to evaluate WR, FL, and compressive strength of the water retentive material. In addition, the compressive strength test, the flexural strength test, and the temperature monitoring test were utilized to evaluate the mechanical performance and the cooling effects of WTCC.

#### *3.1. Water Retention Capacity Test*

The water retentive material should have good WR to store as much as water as possible. The greater WR is, the longer the evaporation time lasts. WR was determined by the following steps:

$$\mathbf{W\_R} = \frac{\mathbf{m\_1} - \mathbf{m\_0}}{\mathbf{V}} \times 100\% \tag{2}$$

where V is the volume of specimens, cm3 .

#### *3.2. Fluidity Test*

The FL was determined via flow cone method according to JTG 3420-2020 [27]. A volume of 1725 mL ± 5 mL of water retentive material was poured into a flow cone by opening the outlet and allowing the water retentive material to free flow out from the flow cone. The flowing time was recorded as the FL. The greater FL was, the better the fluidity was.

#### *3.3. Compressive Strength and Flexural Strength Test*

For the water retentive material, compressive strength test was performed on cylindrical specimens with a height of 50 mm and diameter of 50 mm. The specimens were cured at a temperature of 20 ± 2 ◦C and a humidity of 95% for seven days. A loading rate of 5 mm/min was applied until the specimens failed. The compressive strength (Rc) of the water retentive material was calculated based on Equation (3).

$$\mathbf{R\_{c}} = \frac{\mathbf{P}}{\mathbf{A}}\tag{3}$$

where P is the peak force, kN; and A is the area of upper surface of specimen, mm2 .

For PCC, WTCC, and WCC, both compressive strength and flexural strength were evaluated. Prismatic specimens with a height of 150 mm, a width of 150 mm, and a length of 550 mm were prepared for the measurement of flexural strength. Four point bending test was used to measure the flexural strength. Cubic specimens with height, width, and length of 150 mm were prepared for the compressive strength test [27]. The compressive strength was calculated based on the Equation (3), and the flexural strength (Ff ) was calculated based on the Equation (4). The compressive strength and the flexural strength of the specimens after 7 days, 28 days, and 90 days curing were evaluated.

$$\mathbf{F}\_{\mathbf{f}} = \frac{\mathbf{PL}}{\mathbf{b}\mathbf{h}^2} \tag{4}$$

where L is the length between two fixing supports, mm; and b and h are width and height of specimen, mm.

#### *3.4. Temperature Monitoring Test*

Temperature monitoring test was designed to evaluate the cooling effects of SMA, PCC, WCC, and WTCC. The specimens of PCC, WCC, and WTCC used in the temperature monitoring test had a length of 300 mm, a width of 300 mm, and a height of 100 mm. Vibration compaction was used to prepare the specimen of PCC, WCC, and WTCC. Before

compaction, one temperature sensor was embedded at the depth of 50 mm, and another temperature sensor was embedded at the surface of the center of each specimen. mm. Vibration compaction was used to prepare the specimen of PCC, WCC, and WTCC. Before compaction, one temperature sensor was embedded at the depth of 50 mm, and another temperature sensor was embedded at the surface of the center of each specimen.

f

PL F

where L is the length between two fixing supports, mm; and b and h are width and

Temperature monitoring test was designed to evaluate the cooling effects of SMA, PCC, WCC, and WTCC. The specimens of PCC, WCC, and WTCC used in the temperature monitoring test had a length of 300 mm, a width of 300 mm, and a height of 100

2

bh = (4)

In actual pavement, the heat only can be transferred from the surface of the pavement. To simulate the field condition, a testing box was designed to avoid the heat transferring from the bottom and the side of the specimen. As shown in Figure 3, the testing box was a wood box filled with insulating foam and tested mixtures. The thickness of the insulating foam was 5 cm. The bottom and the side of the specimens were wrapped by the same mixtures with the tested specimens. In actual pavement, the heat only can be transferred from the surface of the pavement. To simulate the field condition, a testing box was designed to avoid the heat transferring from the bottom and the side of the specimen. As shown in Figure 3, the testing box was a wood box filled with insulating foam and tested mixtures. The thickness of the insulating foam was 5 cm. The bottom and the side of the specimens were wrapped by the same mixtures with the tested specimens.

*Materials* **2021**, *14*, x FOR PEER REVIEW 7 of 13

**Figure 3.** Schemes of testing box. **Figure 3.** Schemes of testing box.

height of specimen, mm.

*3.4. Temperature Monitoring Test*

A multi-channel automatic temperature recorder, produced by Hang Zhou Ze Da Instrument Co., Ltd., (Hangzhou, China) was used in the temperature monitoring test. The measuring accuracy was 0.1 °C, and the temperature was recorded every 10 min. Before testing, a mass of 500 mL water was sprinkled on the surface of the specimens to simulate the rainfall. Temperature sensors were connected to the multi-channel automatic temperature recorder. To evaluate the field cooling effects, one day with maximum and minimum air temperatures of 35 °C and 19 °C in summer was selected to perform the temperature monitoring test. A multi-channel automatic temperature recorder, produced by Hang Zhou Ze Da Instrument Co., Ltd., (Hangzhou, China) was used in the temperature monitoring test. The measuring accuracy was 0.1 ◦C, and the temperature was recorded every 10 min. Before testing, a mass of 500 mL water was sprinkled on the surface of the specimens to simulate the rainfall. Temperature sensors were connected to the multi-channel automatic temperature recorder. To evaluate the field cooling effects, one day with maximum and minimum air temperatures of 35 ◦C and 19 ◦C in summer was selected to perform the temperature monitoring test.

#### **4. Results and Discussion 4. Results and Discussion**

#### *4.1. Design of Water Retentive Material*

*4.1. Design of Water Retentive Material*  The composition ratio of fly ash, cement, silica fume, and water in the water retentive material was determined based on WR, FL, and compressive strength. The cement not only provided strength for the water retentive material but also prevented fly ash and silica fume from losing the water retentive material. However, excessive cement may clog the air voids and had a negative effect on the absorption capacity. Based on common sense and practices, the maximum percentage of cement is recommended as 15% of the total mass of fly ash and silica fume [28]. In addition, WR greater than 0.25 g/cm3, FL between 15 and 20 s, and compressive strength greater than 2.0 MPa are gener-The composition ratio of fly ash, cement, silica fume, and water in the water retentive material was determined based on WR, FL, and compressive strength. The cement not only provided strength for the water retentive material but also prevented fly ash and silica fume from losing the water retentive material. However, excessive cement may clog the air voids and had a negative effect on the absorption capacity. Based on common sense and practices, the maximum percentage of cement is recommended as 15% of the total mass of fly ash and silica fume [28]. In addition, WR greater than 0.25 g/cm3 , FL between 15 and 20 s, and compressive strength greater than 2.0 MPa are generally required to ensure workability and strength for the water retentive material [28].

ally required to ensure workability and strength for the water retentive material [28]. The mass ratio of fly ash to silica fume (F/S) was firstly determined. Three F/Ss of 65/35, 60/40, and 55/45 were investigated by the water retention capacity test. Figure 4a The mass ratio of fly ash to silica fume (F/S) was firstly determined. Three F/Ss of 65/35, 60/40, and 55/45 were investigated by the water retention capacity test. Figure 4a shows the WR under different F/S. WR decreased with the decrement of F/S. Results indicate that increasing the percentage of fly ash can increase the WR of the water retentive material. When the F/S was greater than 60/40, the WR could satisfy the requirement of being greater than 0.25 g/cm3 . Secondly, the mass of water to the total mass of fly ash, silica fume, and cement (W/FSC) was determined based on the FL. The fluidities of three W/FSCs of 1.8/1, 2.0/1, and 2.2/1 were evaluated. Figure 4b presents the FL of different W/FSCs under the F/Ss of 65/35 and 60/40. The FL decreased with the increasing W/FSC. Under the same W/FSC, FL under F/S of 60/40 was greater than F/S of 65/35, demonstrating that silica fume had a positive influence on the fluidity of the water retentive material. Under the F/S of 65/35 with W/FSC of 1.8/1 and F/S of 60/40 with W/FSC of 2.0/1, FL satisfies the requirement of between 15 and 20 s. Compared with W/FSC of 2.0/1, the water retentive material under W/FSC of 1.8/1 with less water had better durability

because water had a negative influence on the durability. Thus, the composition of the water retentive material was determined as F/S of 65/35, cement mass of 15% of the total mass of fly ash and silica fume, and W/FSC of 1.8/1. In other words, the mass ratio of fly ash, silica fume, cement, and water was 65:35:15:63.9. Finally, the compressive strength test was performed, and the compressive strength was 2.7 MPa, which is greater than 2.0 MPa. The design procedure of water retentive material is summarized in Figure 5. the water retentive material was determined as F/S of 65/35, cement mass of 15% of the total mass of fly ash and silica fume, and W/FSC of 1.8/1. In other words, the mass ratio of fly ash, silica fume, cement, and water was 65:35:15:63.9. Finally, the compressive strength test was performed, and the compressive strength was 2.7 MPa, which is greater than 2.0 MPa. The design procedure of water retentive material is summarized in Figure 5.

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shows the WR under different F/S. WR decreased with the decrement of F/S. Results indicate that increasing the percentage of fly ash can increase the WR of the water retentive material. When the F/S was greater than 60/40, the WR could satisfy the requirement of being greater than 0.25 g/cm3. Secondly, the mass of water to the total mass of fly ash, silica fume, and cement (W/FSC) was determined based on the FL. The fluidities of three W/FSCs of 1.8/1, 2.0/1, and 2.2/1 were evaluated. Figure 4b presents the FL of different W/FSCs under the F/Ss of 65/35 and 60/40. The FL decreased with the increasing W/FSC. Under the same W/FSC, FL under F/S of 60/40 was greater than F/S of 65/35, demonstrating that silica fume had a positive influence on the fluidity of the water retentive material. Under the F/S of 65/35 with W/FSC of 1.8/1 and F/S of 60/40 with W/FSC of 2.0/1, FL satisfies the requirement of between 15 and 20 s. Compared with W/FSC of 2.0/1, the water retentive material under W/FSC of 1.8/1 with less water had better durability because water had a negative influence on the durability. Thus, the composition of

**Figure 4. Figure 4.**  W WR and FL: (**a**) WR under different F/S; (**b**) FL under different W/FSC. R and FL: (**a**) WR under different F/S; (**b**) FL under different W/FSC.

**Figure 5.** Design procedure of water retentive material. **Figure 5.** Design procedure of water retentive material.

#### *4.2. Preparation of WTCC 4.2. Preparation of WTCC*

The WTCC was prepared by pouring water retentive material into PCC-RA, while WCC was prepared by pouring water retentive material into PCC-SA after 7 days of curing. The flexural strengths of PCC-SA and PCC-RA after 28 days of curing were 4.8 MPa and 4.3 MPa, respectively. The flexural strength of RCC-RA was smaller than The WTCC was prepared by pouring water retentive material into PCC-RA, while WCC was prepared by pouring water retentive material into PCC-SA after 7 days of curing. The flexural strengths of PCC-SA and PCC-RA after 28 days of curing were 4.8 MPa and 4.3 MPa, respectively. The flexural strength of RCC-RA was smaller than RCC-SA because

RCC-SA because the strength of RA was smaller than SA. Based on the specification of design of highway cement concrete pavement of China, the minimum flexural strength

4.0 MPa is specified for light traffic roads [29]. Therefore, PCC-SA could be used for the medium traffic roads, while PCC-RA only could be used for the light traffic roads.

The preparation of WCC and WTCC was based on the following steps: (1) Dust was removed from the surface of the specimens, and some water was sprayed on the surface of the specimens. (2) We placed the specimens on a vibration table and poured the water retentive material on the surface of specimen. The surface of the specimen was covered by a geotextile. (3) We turned on the vibration table until the water retentive material could not infiltrate the specimens. (4) The water retentive material that remained on the surface was removed, and the specimens were cured under the temperature of 20 ± 2 °C

Figure 6a,b show the compressive strength and flexural strength of different pavements after 7 days, 28 days, and 90 days curing, respectively. The compressive strength and flexural strength of WTCC at 28 days is 30.4 MPa and 4.6 MPa, respectively, which satisfies the requirement of medium traffic roads. Even though the WTCC used in the square, bicycle lane, and sidewalk is more appropriate, the WTCC has a potential used

in the medium traffic roads based on the mechanical performance.

and the humidity of 95% for 28 days.

*4.3. Mechanical Performance of WTCC*

the strength of RA was smaller than SA. Based on the specification of design of highway cement concrete pavement of China, the minimum flexural strength of 4.5 MPa is specified for medium traffic roads, and the minimum flexural strength of 4.0 MPa is specified for light traffic roads [29]. Therefore, PCC-SA could be used for the medium traffic roads, while PCC-RA only could be used for the light traffic roads.

The preparation of WCC and WTCC was based on the following steps: (1) Dust was removed from the surface of the specimens, and some water was sprayed on the surface of the specimens. (2) We placed the specimens on a vibration table and poured the water retentive material on the surface of specimen. The surface of the specimen was covered by a geotextile. (3) We turned on the vibration table until the water retentive material could not infiltrate the specimens. (4) The water retentive material that remained on the surface was removed, and the specimens were cured under the temperature of 20 ± 2 ◦C and the humidity of 95% for 28 days.

## *4.3. Mechanical Performance of WTCC*

Figure 6a,b show the compressive strength and flexural strength of different pavements after 7 days, 28 days, and 90 days curing, respectively. The compressive strength and flexural strength of WTCC at 28 days is 30.4 MPa and 4.6 MPa, respectively, which satisfies the requirement of medium traffic roads. Even though the WTCC used in the square, bicycle lane, and sidewalk is more appropriate, the WTCC has a potential used in the medium traffic roads based on the mechanical performance. *Materials* **2021**, *14*, x FOR PEER REVIEW 10 of 13

**Figure 6.** Compressive and flexural strength of different pavements: (**a**) compressive strength; (**b**) flexural strength. **Figure 6.** Compressive and flexural strength of different pavements: (**a**) compressive strength; (**b**) flexural strength.

The compressive strength and the flexural strength increased with the curing time.

The flexural strength of WCC was greater than PCC-SA, and the flexural strength of WTCC was greater than PCC-RA, indicating that the water retentive material functionally improved the flexural strength. After the water retentive material was added into the PCC-SA and the PCC-RA, the pore structures were filled with water retentive materials, leading to AV content decrement. The strength increased with the decrement of AV content, and the self-strength of the water retentive material could also improve the strength of the specimen. In addition, compared with PCC and WTCC, both compressive strength and flexural strength of WCC were the largest. It also demonstrates that the water retentive material and the higher strength of SA had contributions to the strength of the specimen. The compressive strength and the flexural strength increased with the curing time. The flexural strength of WCC was greater than PCC-SA, and the flexural strength of WTCC was greater than PCC-RA, indicating that the water retentive material functionally improved the flexural strength. After the water retentive material was added into the PCC-SA and the PCC-RA, the pore structures were filled with water retentive materials, leading to AV content decrement. The strength increased with the decrement of AV content, and the self-strength of the water retentive material could also improve the strength of the specimen. In addition, compared with PCC and WTCC, both compressive strength and flexural strength of WCC were the largest. It also demonstrates that the water retentive material and the higher strength of SA had contributions to the strength of the specimen.

#### *4.4. Cooling Effects of WTCC 4.4. Cooling Effects of WTCC*

Figure 7 shows the surface temperature of four specimens under the field air temperature. As shown in Figure 7a, the temperature changes showed a consistency with the air temperature. At the start of the test, the temperature of cement concrete pavement was lower than SMA due to a lower heat absorptivity of cement concrete than as-Figure 7 shows the surface temperature of four specimens under the field air temperature. As shown in Figure 7a, the temperature changes showed a consistency with the air temperature. At the start of the test, the temperature of cement concrete pavement was lower than SMA due to a lower heat absorptivity of cement concrete than asphalt mixtures.

significant temperature reduction was found in WTCC.

phalt mixtures. The highest surface temperature appeared at about 15:00, and the surface temperature of SMA was the highest. The highest surface temperatures of SMA,

pared with SMA, PCC, and WCC, the highest surface temperatures of WTCC decreased by 11.4 °C, 5.5 °C, and 4.1 °C, respectively. Figure 7b shows the average surface temperature of the four mixtures. Compared with SMA, PCC, and WCC, the average surface temperatures of WTCC decreased by 2.9 °C, 4.0 °C, and 6.1 °C, respectively. Figure 8a shows the temperature distribution at the depth of 50 mm under the field air temperature. The temperature at the depth of 50 mm of SMA was also the highest. Compared with SMA, PCC, and WCC, the highest temperatures at the depth of 50 mm of WTCC decreased by 10.3 °C, 6.1 °C, and 4.6 °C, respectively. Figure 8b shows the average of the temperature at the depth of 50 mm. Compared with SMA, PCC, and WCC, the average surface temperatures of WTCC decreased by 3.5 °C, 4.0 °C, and 6.4 °C, respectively. A

ature.

The highest surface temperature appeared at about 15:00, and the surface temperature of SMA was the highest. The highest surface temperatures of SMA, PCC, WCC, and WTCC were 62.9 ◦C, 57.0 ◦C, 55.6 ◦C, and 51.5 ◦C, respectively. Compared with SMA, PCC, and WCC, the highest surface temperatures of WTCC decreased by 11.4 ◦C, 5.5 ◦C, and 4.1 ◦C, respectively. Figure 7b shows the average surface temperature of the four mixtures. Compared with SMA, PCC, and WCC, the average surface temperatures of WTCC decreased by 2.9 ◦C, 4.0 ◦C, and 6.1 ◦C, respectively. Figure 8a shows the temperature distribution at the depth of 50 mm under the field air temperature. The temperature at the depth of 50 mm of SMA was also the highest. Compared with SMA, PCC, and WCC, the highest temperatures at the depth of 50 mm of WTCC decreased by 10.3 ◦C, 6.1 ◦C, and 4.6 ◦C, respectively. Figure 8b shows the average of the temperature at the depth of 50 mm. Compared with SMA, PCC, and WCC, the average surface temperatures of WTCC decreased by 3.5 ◦C, 4.0 ◦C, and 6.4 ◦C, respectively. A significant temperature reduction was found in WTCC. *Materials* **2021**, *14*, x FOR PEER REVIEW 11 of 13 *Materials* **2021**, *14*, x FOR PEER REVIEW 11 of 13

**Figure 7.** Surface temperature under field air temperature: (**a**) temperature variation curve; (**b**) average surface temper-**Figure 7.** Surface temperature under field air temperature: (**a**) temperature variation curve; (**b**) average surface temperature. **Figure 7.** Surface temperature under field air temperature: (**a**) temperature variation curve; (**b**) average surface temperature.

**Figure 8.** Temperature at the depth of 50 mm under the field air temperature: (**a**) temperature variation curve; (**b**) average temperature. **Figure 8.** Temperature at the depth of 50 mm under the field air temperature: (**a**) temperature variation curve; (**b**) average temperature. **Figure 8.** Temperature at the depth of 50 mm under the field air temperature: (**a**) temperature variation curve; (**b**) average temperature.

The temperature of WCC was slightly smaller than PCC due to the heat dissipation through water evaporation of the water retentive material. However, as shown in Figures 7 and 8, the temperature of WCC approached the same as the temperature of PCC after 18:00. Water in the water retentive material was consumed during continuous evaporation. When the water was exhausted, temperature reduction through water The temperature of WCC was slightly smaller than PCC due to the heat dissipation through water evaporation of the water retentive material. However, as shown in Figures 7 and 8, the temperature of WCC approached the same as the temperature of PCC after 18:00. Water in the water retentive material was consumed during continuous evaporation. When the water was exhausted, temperature reduction through water The temperature of WCC was slightly smaller than PCC due to the heat dissipation through water evaporation of the water retentive material. However, as shown in Figures 7 and 8, the temperature of WCC approached the same as the temperature of PCC after 18:00. Water in the water retentive material was consumed during continuous evaporation. When the water was exhausted, temperature reduction through water evaporation

evaporation failed. Therefore, it is suggested to supplement water for pavement at 12:00 to prolong and enhance the cooling effects. This work can be done by incorporating it in

evaporation failed. Therefore, it is suggested to supplement water for pavement at 12:00 to prolong and enhance the cooling effects. This work can be done by incorporating it in

temperature of WTCC was still the lowest, even when the water in the water retentive

Based on the results, WTCC presents a great cooling effect via the combination of porous cement concrete, a thermal resistant aggregate, and water retentive material. WTCC has potential to efficiently mitigate the UHI effects and be used in medium traffic

Based on the results, WTCC presents a great cooling effect via the combination of porous cement concrete, a thermal resistant aggregate, and water retentive material. WTCC has potential to efficiently mitigate the UHI effects and be used in medium traffic

In this study, water retentive material and WTCC were developed to alleviate the UHI effects. The mechanical performance and the cooling effects of WTCC were evalu-

In this study, water retentive material and WTCC were developed to alleviate the UHI effects. The mechanical performance and the cooling effects of WTCC were evalu-

material was exhausted.

material was exhausted.

roads.

roads.

**5. Conclusions**

**5. Conclusions**

failed. Therefore, it is suggested to supplement water for pavement at 12:00 to prolong and enhance the cooling effects. This work can be done by incorporating it in the cleaning work of pavements. Because WTCC uses thermal resistant aggregates, the temperature of WTCC was still the lowest, even when the water in the water retentive material was exhausted.

Based on the results, WTCC presents a great cooling effect via the combination of porous cement concrete, a thermal resistant aggregate, and water retentive material. WTCC has potential to efficiently mitigate the UHI effects and be used in medium traffic roads.

#### **5. Conclusions**

In this study, water retentive material and WTCC were developed to alleviate the UHI effects. The mechanical performance and the cooling effects of WTCC were evaluated and compared with SMA, PCC, and WCC. Several conclusions could be obtained from the study.

**Author Contributions:** Conceptualization, X.W. and X.J.; methodology, X.H.; validation, X.J.; formal analysis, X.H. and B.C.; investigation, X.H.; resources, H.C. and B.C.; data curation, X.W.; writing original draft preparation, X.W.; writing—review and editing, X.H.; visualization, X.H.; supervision, X.J.; funding acquisition, X.W. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by National Natural Science Foundation of China (52008333), Natural Science Basic Research Program of Shaanxi (2020JQ-680), China Postdoctoral Science Foundation (2020M673354), and Scientific Research Program Funded by Shaanxi Provincial Education Department (20JK0711).

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

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data presented in this study are available on request from the correspondence author.

**Acknowledgments:** The authors would like to express sincere thanks to the National Natural Science Foundation of China, Natural Science Basic Research Program of Shaanxi, China Postdoctoral Science Foundation, and Shaanxi Provincial Education Department.

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

## **References**

1. Santamouris, M. Using cool pavements as a mitigation strategy to fight urban heat island—A review of the actual developments. *Renew. Sustain. Energy Rev.* **2013**, *26*, 224–240. [CrossRef]


3.5.3. Opportunities

Growing sustainability awareness in the construction industry has led to the search for sustainable materials that can replace OPC in cementitious materials. Due to its chemical properties and the fact that it is derived from agricultural waste, date palm frond biochar is an excellent alternative source of revenue for developing sustainable concrete. Saudi Arabia ranks among the world's leading date-producing countries. As a result of the high production of dates, the date palm industry produces a tremendous amount of agricultural waste. If these wastes are improperly disposed of in the environment, they could pose a fire and safety risk. In addition, valuable land spaces could be depleted, and the aesthetics of the environment might be impacted. The processing of these date palm fronds into biochar would provide an opportunity to efficiently manage these waste materials and use them as a raw material for making green concrete. Further, converting these wastes into valuable resources would entail a monetary value for date palm factories, opening up another source of revenue.

The application of date palm fronds biochar in building materials has been shown to improve the mechanical properties of building materials and enhance the durability of composites under extreme environmental conditions. The improved properties suggest that biochar-containing building materials perform equally or even better than those without [4,58–61]. Therefore, there is a massive opportunity for date palm fronds derived from biochar-based concrete to be used for various building applications for a better design life. Due to its wide range of applications and vast production, concrete has a substantial carbon footprint, contributing to 8% of the global carbon dioxide emissions [5]. Therefore, it is imperative to look for pathways for reducing emissions within the cement and concrete industry to reduce its environmental impact [4]. The use of date palm fronds-derived biochar in building materials has the potential to reduce carbon footprints and mitigate climate change [62]. The ability of biochar to sequester carbon in stable forms and capture CO2 directly from the atmosphere in building materials and the addition of CO2-saturated biochar have a vital role. Even with a lack of studies on this topic, building materials that contain date palm fronds derived from biochar have superb possibilities for reducing carbon footprints and mitigating climate change [63].


5. Experimental results and discussion

Two coordinate sets of 15 terminal nodes are randomly created based on varied distribution topology of terminal nodes in VLSI system on a defined two dimensional 100 100 search space. Coordinate sets for nearly Uniform distribution and Bivariate distribution are graphically represented in Figures 4 and 5 respectively.

5.1. Experiment A

Experiments on PSO-W as well as on the modified algorithms PSO-ST [20] and PSO-SAAC are performed separately for two said coordinate sets to interconnect the terminal points for each set and to return the minimum cost of interconnection correspondingly. The minimum interconnection VLSI global routing cost, the average interconnection VLSI global routing cost over the 25 simulations of the algorithms and the corresponding standard deviations are recorded.

Performance Comparison of PSO and Its New Variants in the Context of VLSI Global Routing

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For nearly uniform distribution of terminal nodes in VLSI layout, PSO-SAAC works best in compared to the other two algorithms. In SET 1 '338' is achieved as the minimum interconnection global cost value for PSO-SAAC, given in Figure 6. From Table 1 it can be analyzed that for bivariate distribution of terminal nodes in VLSI layout, self-tuned acceleration constant controlling mechanism for PSO-ST outruns the other two algorithms. In random uniform distribution environment, PSO-ST generates lowest minimum interconnection cost as 253,

Test case gbest value PSO-W PSO-ST PSO-SAAC SET 1 Average 354.5 348.4 341.7

SET 2 Average 256.7 254.9 257.3

Table 1. Comparison of PSO-W with PSO-ST and PSO-SAAC.

Figure 6. Minimum 'cost' Steiner tree obtained for PSO-SACC in SET 1.

Minimum 350 343 338

Minimum 253 253 255

The results of average gbest and minimum gbest are summarized in Table 1.

Experiments on all the algorithms are performed 25 times for each of these coordinate sets of varied distribution topologies in VLSI system. The population size of the swarms has been set as 100 and maximum iteration of 75 is used for all the algorithms.

Figure 4. Nearly uniform distribution of terminal nodes on 100 100 search space.

Figure 5. Bivariate distribution of terminal nodes on 100 100 search space.

## 5.1. Experiment A

5. Experimental results and discussion

72 Particle Swarm Optimization with Applications

cally represented in Figures 4 and 5 respectively.

as 100 and maximum iteration of 75 is used for all the algorithms.

Figure 4. Nearly uniform distribution of terminal nodes on 100 100 search space.

Figure 5. Bivariate distribution of terminal nodes on 100 100 search space.

Two coordinate sets of 15 terminal nodes are randomly created based on varied distribution topology of terminal nodes in VLSI system on a defined two dimensional 100 100 search space. Coordinate sets for nearly Uniform distribution and Bivariate distribution are graphi-

Experiments on all the algorithms are performed 25 times for each of these coordinate sets of varied distribution topologies in VLSI system. The population size of the swarms has been set Experiments on PSO-W as well as on the modified algorithms PSO-ST [20] and PSO-SAAC are performed separately for two said coordinate sets to interconnect the terminal points for each set and to return the minimum cost of interconnection correspondingly. The minimum interconnection VLSI global routing cost, the average interconnection VLSI global routing cost over the 25 simulations of the algorithms and the corresponding standard deviations are recorded. The results of average gbest and minimum gbest are summarized in Table 1.

For nearly uniform distribution of terminal nodes in VLSI layout, PSO-SAAC works best in compared to the other two algorithms. In SET 1 '338' is achieved as the minimum interconnection global cost value for PSO-SAAC, given in Figure 6. From Table 1 it can be analyzed that for bivariate distribution of terminal nodes in VLSI layout, self-tuned acceleration constant controlling mechanism for PSO-ST outruns the other two algorithms. In random uniform distribution environment, PSO-ST generates lowest minimum interconnection cost as 253,

Table 1. Comparison of PSO-W with PSO-ST and PSO-SAAC.

Figure 6. Minimum 'cost' Steiner tree obtained for PSO-SACC in SET 1.

given in Figure 7. It is also seen that acceleration constant tuning mechanism of PSO improves the average interconnection cost of the VLSI global best parameter.

coordinate set which have been considered. The results of minimum interconnect cost, average

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The Minimum Rectilinear Spanning Tree (RMST) for minimum interconnect cost generated for the said VLSI topologies in case of all algorithms are shown in Figures 8, 9, and 10. It reveals that the algorithm PSO-MU generate lowest minimum global best value as well as minimum mean value in all two coordinate sets. This indicates that this algorithm PSO-MU, in comparison to PSO-W and PSO-C, ensure efficient VLSI global routing cost minimization and better

It is observed from Table 3 that for Coordinate Set 1, gbest value of PSO –MU is found to be 329 where execution time of this algorithm is much greater than PSO-W. Runtime of PSO-C is found to be 101.51 compared to 85.48 for PSO-MU algorithm. This implies that PSO-MU

> Minimum 350 345 329 System time 52.825 101.51 85.48

> Minimum 253 254 248 System time 49.05 86.01 66.96

Test case gbest value PSO-W PSO-C PSO-MU SET 1 Average 354.5 350.4 336.8

SET 2 Average 256.7 256 250.4

Table 3. Comparison of PSO variants over average, minimum gbest value and system time.

Figure 8. Minimum 'interconnection cost' Steiner Tree obtained for PSO-W in SET 1.

cost and average execution time of all algorithms are recorded on Table 3.

convergence.

So, it can be safely stated that for nearly uniform distribution PSO-SAAC and for increased random bivariate distributions PSO-ST reduces the cost of RMST, constructed by interconnecting the terminal nodes. So RSMT problem of graphs can be effectively managed and thereby the VLSI interconnect length is reduced to a great extent.

It is also observed that from Table 2, that standard deviation value for PSO-SAAC is lowest for SET 1 whereas PSO-ST achieves lowest standard deviation value for SET 2. This implies that for nearly uniform and less random distribution, self-adaptive mechanism of PSO ensures more consistency while self-tuned mechanism of PSO is more consistent in case of highly random distribution of terminal nodes in the defined search space.

## 5.2. Experiment B

The experiments are performed first on weighted PSO (PSO-W) and then on PSO with constriction factor (PSO-C) and lastly on PSO with mutation algorithm (PSO-MU) for all two

Figure 7. Minimum 'cost' Steiner tree obtained for PSO-ST in SET 2.

Table 2. Standard deviation of gbest values.

coordinate set which have been considered. The results of minimum interconnect cost, average cost and average execution time of all algorithms are recorded on Table 3.

given in Figure 7. It is also seen that acceleration constant tuning mechanism of PSO improves

So, it can be safely stated that for nearly uniform distribution PSO-SAAC and for increased random bivariate distributions PSO-ST reduces the cost of RMST, constructed by interconnecting the terminal nodes. So RSMT problem of graphs can be effectively managed

It is also observed that from Table 2, that standard deviation value for PSO-SAAC is lowest for SET 1 whereas PSO-ST achieves lowest standard deviation value for SET 2. This implies that for nearly uniform and less random distribution, self-adaptive mechanism of PSO ensures more consistency while self-tuned mechanism of PSO is more consistent in case of highly

The experiments are performed first on weighted PSO (PSO-W) and then on PSO with constriction factor (PSO-C) and lastly on PSO with mutation algorithm (PSO-MU) for all two

Test case PSO-W PSO-ST PSO-SAAC

SET 1 7.77 0.71 5.41 SET 2 1.94 1.88 4.12

the average interconnection cost of the VLSI global best parameter.

and thereby the VLSI interconnect length is reduced to a great extent.

random distribution of terminal nodes in the defined search space.

Figure 7. Minimum 'cost' Steiner tree obtained for PSO-ST in SET 2.

Table 2. Standard deviation of gbest values.

5.2. Experiment B

74 Particle Swarm Optimization with Applications

The Minimum Rectilinear Spanning Tree (RMST) for minimum interconnect cost generated for the said VLSI topologies in case of all algorithms are shown in Figures 8, 9, and 10. It reveals that the algorithm PSO-MU generate lowest minimum global best value as well as minimum mean value in all two coordinate sets. This indicates that this algorithm PSO-MU, in comparison to PSO-W and PSO-C, ensure efficient VLSI global routing cost minimization and better convergence.

It is observed from Table 3 that for Coordinate Set 1, gbest value of PSO –MU is found to be 329 where execution time of this algorithm is much greater than PSO-W. Runtime of PSO-C is found to be 101.51 compared to 85.48 for PSO-MU algorithm. This implies that PSO-MU

Table 3. Comparison of PSO variants over average, minimum gbest value and system time.

Figure 8. Minimum 'interconnection cost' Steiner Tree obtained for PSO-W in SET 1.

algorithm outperforms the performance of conventional PSO-W and PSO-C algorithm while reducing the Timing budget with respect to PSO-C algorithm in context to VLSI global routing. In order to analyze the consistency of these algorithms, the standard deviation (SD) values are calculated for all algorithms on each of the two coordinate sets and are recorded in the Table 4. SD value of PSO-C is found to be 0.71 and 2.25 for the two coordinate sets. These values are much lower compared to all other SD values of PSO-W and PSO-MU ensuring robustness although sacrificing system execution time of the algorithm independent of the distribution complexities of the search space in VLSI layout. This implies that PSO-C although generates higher value of global routing interconnection cost as well as system execution time compared to PSO-W and PSO-MU, it exhibits robustness of the algorithm throughout all varied distribu-

Test case PSO-W PSO-C PSO-MU SET 1 7.77 0.71 5.65 SET 2 1.94 1.88 3.83

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This chapter intends variants developed on Particle Swarm Optimization algorithm to resolve the global routing problem in VLSI domain. Simultaneously the controlling of acceleration constant in PSO has been verified for the VLSI routing problem. Lastly, a proportional analysis is done amongst the pre mentioned algorithms beside three variants of PSO, which have been recognized as decent routing algorithms in VLSI design. Researches are piloted to inspect the optimization property, rate of convergence, computational time and robustness of the algorithms including the ways by which algorithms work proficiently in problem space with

The outcomes demonstrates that from the standpoint of topologically dissimilar problem spaces of VLSI domain, the general performance of PSO-ST [20] is very agreeable, however PSO-SAAC executes finest in an approximately uniform distributed problem space. It has also been observed that the performance of PSO-C and PSO-MU are unhampered of the diverse distribution of VLSI global routing problem space. The performance of the algorithm PSO-MU preserves a balance between the optimization and convergence rate. Although PSO-MU is realized to be steady in random problem space [22], PSO-C is appeared to be the best algo-

Therefore the chapter indicated the exclusive merits and demerits of the PSO algorithm and its variants, well-matched for solving the wire-length minimization problem of global routing in VLSI physical design. It is projected that in the situation of VLSI global routing optimization, the paradigm of hybridization with essence of genetics can contest with the functioning of PSO conventional ones and can exhibit enhanced performance. Hence the global routing problem

tion topologies of the terminal nodes in the said VLSI layout.

dissimilar distributive topologies of VLSI layout.

rithm in the perspective of robustness.

6. Conclusion

Table 4. Standard deviation of gbest values.

Figure 9. Minimum 'interconnection cost' Steiner Tree obtained for PSO-C in SET 1.

Figure 10. Minimum 'interconnection cost' Steiner Tree obtained for PSO-MU in SET 1.

Table 4. Standard deviation of gbest values.

algorithm outperforms the performance of conventional PSO-W and PSO-C algorithm while reducing the Timing budget with respect to PSO-C algorithm in context to VLSI global routing.

In order to analyze the consistency of these algorithms, the standard deviation (SD) values are calculated for all algorithms on each of the two coordinate sets and are recorded in the Table 4. SD value of PSO-C is found to be 0.71 and 2.25 for the two coordinate sets. These values are much lower compared to all other SD values of PSO-W and PSO-MU ensuring robustness although sacrificing system execution time of the algorithm independent of the distribution complexities of the search space in VLSI layout. This implies that PSO-C although generates higher value of global routing interconnection cost as well as system execution time compared to PSO-W and PSO-MU, it exhibits robustness of the algorithm throughout all varied distribution topologies of the terminal nodes in the said VLSI layout.


**6. Conclusions**

**Figure 7** presents the change of the thermal energy *Q*fr‐bw‐total during the 30 h refrigeration of the studied logs, which is calculated according to Eq. (32). The change of this energy is similar to that of the energy *Q*fr‐bw(see **Figure 6**, left). At the end of the 30 h freezing, the energy *Q*fr‐bw‐total reaches the following values:

This paper presents a methodology for mathematical modeling and research of two mutually connected problems: 2D nonstationary temperature distribution in logs subjected to refrigeration and change in two important energy characteristics of the bound water in logs during its freezing—thermal energy of the phase transition of the bound water in 1 m3 wood from liquid into solid state, *Q*fr‐bw, and latent thermal energy of the bound water, *Q*Lat‐bw, which is released in 1 m3 of the logs

Mathematical descriptions and an approach for computing of the energies *Q*fr‐bw and *Q*Lat‐bw during the freezing of the bound water at temperatures below �1°C have been carried out. These descriptions are introduced in our own 2D nonlinear mathematical model of the 2D heat distribution in logs during their refrigeration at convective boundary conditions. The model was transformed in a form suitable for programming with the help of explicit schemes of the finite difference method,

A software program for numerical solution of the mathematical model and computation of 2D nonstationary change of the temperature in logs subjected to refrigeration and of the thermal energies *Q*fr‐bw and *Q*Lat‐bw has been prepared in Fortran, which has been input in the calculation environment of Visual Fortran

With the help of the program, computations for the determination of the energies *Q*fr‐bw and *Q*Lat‐bw and their difference, *Q*fr‐bw‐total ¼ *Q*fr‐bw � *Q*Lat‐bw, have been

which excludes the necessity of any simplifications of the model.

5.992 kWh�m�3 for P1 and 6.657 kWh�m�3 for S1.

*Change in Q*fr‐bw‐total *during the refrigeration of the studied logs.*

**5. Discussions**

**Figure 7.**

*Low-temperature Technologies*

during water crystallization.

Professional developed by Microsoft.

**126**

Good adequacy and precision of the model toward the results from wide own experimental studies allow the carrying out of various calculations with the model, which are connected to the nonstationary temperature distribution and energy characteristics of logs from different wood species during their refrigeration. The mathematical model, after its connection with other our model of the logs' defrosting process [9, 10], could be input into the software of programmable controllers for optimized model-based automatic control [8, 20, 21, 35] of thermal treatment of frozen logs in the production of veneer.

The approach for the computation of the thermal energies of the bound water in logs during their refrigeration could be used for the creation of analogous models for the computation of the temperature distribution and the energy required for the refrigeration of different capillary porous materials (fruits, vegetables, meet, meet products, etc.).

#### **Nomenclature**


**Author details**

(at temperatures above 150°C), a monotonous increase in conductivity begins, caused by the thermal activation of charge carriers from energy levels of 0.63 eV and 0.35 eV, respectively. The electrical conductivity of TiO2 coatings decreases from 4 108 Ohm1 m1 to 1 1010 Ohm1 m1 with increasing temperature from room temperature to 250°C and increases to 1 107 Ohm1 m1 with

*AFM surface microtopography of the dielectric layers (a) MgO, (b) TiO2, and (c) Al2O3 [2].*

As can be seen from the temperature dependences of the electrical conductivity of the dielectric layers for an alternating current case, in all investigated coating systems with increasing frequency, the magnitude of the electrical conductivity increases linearly. The increase in *σ*(*ω*) is due to the delay of slow polarization mechanisms. Moreover, the exponent *n* in the equation *σ*(*ω*) = *ωn* for the studied materials differs: for the Al2O3 layers *n* = 0.2, whereas for MgO *n* = 0.5. For titanium

Thus, the peculiarities of formation of the structure, adhesive, micromechanical,

obtained by ion-plasma sputtering were established. An optimal mode of formation of Al2O3, TiO2, and MgO dielectric layers was also determined: the gas pressure in the range Р = (1.5–4) 102 mmHg, the arc current in the range I = 30–40 A, the

When selecting the material for the substrate and dielectric layer during the design of a film heating element, it is necessary to evaluate the type and order of

The existing methods for producing insulating coatings on the surface of corrosion-resistant steels are analyzed. It is shown that the CVD methods (ionplasma deposition of metal oxide metal) of deposition on stainless steel substrates

and electrophysical properties of the Al2O3, TiO2, and MgO dielectric layers

displacement potential on substrate Е = 60 V, and the time τ = 20 min.

values of the dielectric losses that occur under operating conditions.

increasing temperature up to 400°C [2].

*Engineering Steels and High Entropy-Alloys*

oxide coatings, it increases to 0.9.

**4. Conclusion**

**76**

**Figure 19.**

Zoia Duriagina1,2\*, Taras Kovbasyuk1 , Volodymyr Kulyk1 , Andriy Trostianchyn1 and Tetiana Tepla1

1 Lviv Polytechnic National University, Lviv, Ukraine

2 John Paul II Catholic University of Lublin, Lublin, Poland

\*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.


**1. Introduction**

Plasmonics has the fascinating ability to localize and guide light wave at the deep subwavelength scale, becomes an inter-discipline merging photonics with electronics [1–6]. Surface plasmons are free electron oscillations induced by optical methods at the metal surfaces. Both localized and propagated surface plasmons excited in metal nanoparticles and nanowires are of great interest. They not only break the diffraction limit but also allow

© 2016 The Author(s). Licensee InTech. 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. © 2018 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.

to guide light in various geometries such as 90° bending [1]. This promises the scaling of optical devices down to the diffraction limit for miniaturized photonic circuits. The localized surface plasmons have the functionality to scatter, absorb and squeeze light into nanometer scale, providing large enhancements of local near-fields [7]. It holds the potential applications in data storage, light energy generation, sub-wavelength optics, nano-optical tweezers, biophotonics and nanoscopy [8–11]. Gold nanoparticles with sphere/rod shapes and size below 100 nm are highly investigated for many useful applications, such as non/radiative enhancement of nano-crystals [12], inter-particle coupling effect [13], single particle plasmon spectroscopy [14–16], plasmonic sensing [17–19], plasmonic photocatalysis [20–22], and so on. Different from the localized surface plasmons of individual nanoparticles, the propagated surface plasmons existing at flat/curved surfaces in metallic planes, films, and wires also exhibit intriguing plasmonic phenomena [23]. The propagation length of surface plasmon modes is inevitably limited by metallic absorption, could also be strongly confined in the lateral section normal to propagation direction. This implies that plasmonic waveguides could transport larger bandwidth of information than that of conventional photonic waveguides. However, there is a trade-off between propagation loss and mode confinement in plasmonic waveguides [24]. To balance this trade off, an alternative method by seamlessly integrating photonic waveguides into plasmonic waveguides can be used [25]. Silver nanowires usually act as plasmonic waveguides with lateral size of 200−300 nm and axial length up to 10 μm, exhibiting many interesting applications. For example, plasmonic interference [26], waveparticle duality [27], remote excitation of Raman scattering [28–30], long-distance plasmonic gain [31–33], broadside nano-antennas [34], etc. It is impossible to introduce every result on plasmonics in this short chapter. In the following sections, we will specifically describe some novel results with gold nanorods/nanospheres and silver nanowires for achieving optical energy generation, propagation, and conversion.


**4. Discussion**

This study investigated the relationship among self-reported history of childhood maltreatment, FA, and ED symptom severity in a large sample of consecutively recruited patients with ED. Patients with FA reported more frequent histories of childhood maltreatment and presented with more severe ED symptoms as assessed by the EDI-2. In addition, the strong correlation between YFAS and EDI-2 scores suggested that FA and ED symptom severity may be tightly related, while childhood maltreatment was less strongly related to FA. Emotional abuse seems to be the most important type of childhood maltreatment affecting ED symptom severity. In addition, our findings revealed evidence of an indirect effect between all types of childhood maltreatment and ED symptom severity via FA. The strongest of these indirect or mediated effects was related to physical neglect followed by emotional abuse. Moreover, a direct effect relationship between childhood maltreatment and ED symptom severity emerged for the emotional and sexual abuse dimensions. Accordingly, our findings highlight the specific importance of FA in mediating the impact of physical neglect of the clinical severity of patients with any type of ED. Although cross-sectional, these findings are consistent with a model in which retrospective childhood maltreatment, especially physical neglect, might precipitate or constitute a risk factor for FA which may later predispose for, maintain, and/or exacerbate ED symptoms. The role of FA as a mediating factor of in the relationship between retrospective childhood maltreatment and ED warrants further exploration in longitudinal observational studies.

Previous work examined the relationship between trauma exposure and FA. The large cross-sectional cohort study by Mason et al. described above revealed that the likelihood of reporting FA increased with the number of lifetime PTSD symptoms, with the prevalence of FA in women with the greatest number of PTSD symptoms more than twice that of women with neither PTSD symptoms nor trauma histories [13]. Moreover, cross-sectional evidence of relationships between childhood maltreatment and FA and between FA and binge eating was found individuals with higher weight [25]. Further support for this relationship was provided by a comparative study in which individuals with FA reported greater severity of PTSD symptoms as compared to controls [17]. Finally, Stojek et al. revealed that FA severity mediated the association between childhood maltreatment and insulin resistance in women with type 2 diabetes [26]. These cumulative findings, together with ours, suggest a relationship between traumatic exposure and history and FA, as well as other dimensions of disinhibition related to food or substances. Previous work suggested that, at the neurobiological level, both the emotional and the motivational circuits in the brain seem to be affected after exposure to childhood maltreatment [27]. These effects may be associated with disruptions to the experience of inner cues related to the regulation of food and eating, for example, through the effects of stress hormones such as glucocorticoids on the cerebral cortex and limbic system, which may affect the patient's impulse control [27]. These disruptions and the development of maladaptive behavioral patterns related to food may then increase risk for several types of ED especially those that include bingeing behaviors [28,29].

Consistent with this, in our sample, BN was more prevalent in the group of patients reporting FA as compared to the group without FA. This is further in line with findings of relatively recent studies in which FA was found in as many as 96% of patients with BN with a tendency for FA severity to decrease over the course of effective management of BN [30,31]. In a recent study aiming to characterizing FA as a phenotypical construct in patients with different types of EDs and obesity via a factor analysis, results suggested that patients with FA and BN presented with more severe ED psychopathology [32]. Moreover, other work suggested that, among women with a high BMI, the presence of a relationships between early life adversities and FA may be underpinned by specificities in brain regions implicated in reward and emotional regulation [33–35]. Similarly, patients with PTSD were described to be at higher risk for FA and EDs due to the potential mediating role of emotional dysregulation [36]. In addition to affecting the activation pattern and connectivity in brain reward circuits, acute and chronic exposure to stress is considered to affect the hypothalamic–pituitary–adrenal axis, leading to multiple pathological cascades that may induce the development of food craving and addiction, as well as symptoms of depression [37–39].

The varying findings across the dimensions of childhood maltreatment in our mediation analyses suggest that the relationship between childhood maltreatment and ED symptoms may follow a different pathway depending on the subtype of maltreatment. Indeed, this is consistent with evidence from studies conducted in the past few decades indicating that specific types of childhood maltreatment may be differentially associated with particular types of disordered eating [5,8,40–43]. Thus, for example, in a large cohort of American young adults, individuals with a history of physical abuse only displayed a higher tendency toward fasting and skipping meals [39]. In contrast, emotional abuse seems to be most consistently related to EDs symptoms, with evidence supporting a mediated pathway via emotional dysregulation [42,43]. In addition, emotional abuse was found to predict higher eating, shape and weight concerns, and poorer functioning in patients with EDs independently of the presence of other comorbidities [5]. Consistent with this, in our study, of the five dimensions of childhood maltreatment assessed, emotional abuse presented the strongest relationship with ED symptom severity. Furthermore, our findings from the mediation analysis revealed that emotional abuse presented the highest total effect of childhood maltreatment on ED symptoms with direct and indirect effects being globally in the same range. The direct effect of emotional abuse in our mediation model predicting ED symptom severity may also reflect the presence of other contributing factors, such as emotional dysregulation, which was not been included here. Further research examining the role of emotional dysregulation in these relationships is warranted.

Our most interesting finding is related to the fact that the strongest indirect effect of retrospective childhood maltreatment on current ED symptom severity via FA emerged for physical neglect. Moreover, physical neglect's effect on ED symptom severity was only mediated via FA. Physical neglect refers to the failure to provide a child with basic necessities of life such as food and clothing [44]. Brain maturation via myelination, synaptic plasticity, and the release of neurotransmitters depends largely on the prenatal and postnatal nutritional status of children and adolescents [45]. Indeed, it was

shown that parental neglect is an intervening factor in the association between food-approaching appetitive traits and higher weight in children [46]. Accordingly, we can speculate that physical neglect may lead to brain maturation difficulties that may increase risk for FA and, subsequently, an ED.

Patients with EDs and a history of childhood maltreatment may benefit from care that specifically targets this history [47]. Furthermore, the symptom pathway leading to an ED in individuals with a history of childhood maltreatment has been described as specific to this group. Thus, overvaluation of weight and body shape may lead to feelings of loss of control followed by depressive symptoms and, subsequently, overeating [48]. Tailoring of usual treatment protocols to account for these pathways may help to improve clinical outcomes. Given the evidence found in this study for the mediating role of FA, it would be interesting to evaluate whether, in addition to the usual treatment, therapeutic strategies specifically targeting FA might improve overall prognosis. The presence of a history of physical neglect should raise the clinicians' index of suspicion for the presence of FA. In this regard, in case FA is confirmed as a comorbid clinical entity accompanying the ED (after using screening tools such as YFAS), the treatment of FA clinical dimensions and its overall impact on ED symptoms should be assessed in future studies. Accordingly, known suggested treatment protocols such as combining pharmacotherapies (opiate antagonists) and psychotherapies (such as cognitive behavioral therapy and psychodynamic group treatments) may be successful in targeting FA clinical dimensions and, subsequently, ED symptom severity [49,50].

The current study includes several limitations. First, all assessments (other than ED diagnosis) were self-reported which might constitute a source of bias. Indeed, participants with more severe clinical dimensions of ED may more easily recall incidents of childhood maltreatment. Second, the study is cross-sectional and retrospective in its assessment of childhood maltreatment, which limits the extent to which the directionality of relationships can be inferred from the findings. Furthermore, the lack of a nonclinical control group of individuals without EDs limited the extent to which confounding factors could be controlled. Finally, EDs were considered as a spectrum of disorders manifesting in different psychopathological dimensions as reflected by the EDI-2 score. However, in the current study only a composite score of ED symptom severity was used, and future work aiming to clarify the relationships among childhood maltreatment, FA, and different dimensions of disordered eating would be valuable.

## **5. Conclusions**

In conclusion, although cross-sectional, our findings support the existence of a mediated relationship between retrospective childhood maltreatment and ED, via FA, especially in the presence of a history of physical neglect. Patients with severe ED symptoms and a history of childhood maltreatment should be systematically assessed for the presence of FA. Moreover, when childhood maltreatment is documented in patients with ED, tailoring treatment plans to specifically address FA should be considered.

**Author Contributions:** Conceptualization, R.B.K. and S.G.; methodology, R.B.K., G.S., A.A.-C., and S.G.; software, R.B.K., G.S., M.S., and A.A.-C.; validation, S.R., S.I., R.R., P.C., and S.G.; formal analysis, R.B.K., G.S., and S.G.; investigation, M.S., L.M., P.L., and E.R.; resources, S.G. and M.S.; data curation, M.S. and G.S.; writing—original draft preparation, R.B.K., G.S., and S.G.; writing—review and editing, R.B.K., S.R., S.I., R.R., P.C., and S.G.; visualization, R.B.K. and G.S.; supervision, S.G.; project administration, M.S. and S.G.; funding acquisition, S.G. All authors have read and agreed to the published version of the manuscript.

**Funding:** This study received financial support from CHRU Montpellier grant number [UF 9804] And The APC was funded by CHRU Montpellier. The CHRU Montpellier had no role in the design, analysis, interpretation, or publication of this study.

**Acknowledgments:** This study received financial support from CHRU Montpellier. CHRU Montpellier had no role in the design, analysis, interpretation, or publication of this study.

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


**5.4 Psoriasis**

Psoriasis is a common chronic skin disease causing red and itchy scaly patches on the scalp, knees, elbows, and trunk. The "Phagoburn project" aims to reduce bacterial growth and reduce the incidence of psoriasis in patients with severe inflammation and infection. "Phagobon" has been used in the treatment of phage cures to treat *E. coli* and *Pseudomonas aeruginosa* diseases. Phase I/II clinical trials were established in France, Belgium, and Switzerland. Although this project is a breakthrough in phage medical studies, *in vitro* trials and clinics are still needed to gain widespread acceptance in the use of the therapeutic phage to treat people with pathogenic diseases or MDR. A biodegradable polymer wound dressing called, "PhagoBioDerm" is impregnated with numerous antimicrobial elements containing the phage cocktail Pyophage, and the dressing exhibited a slow degradation and presentation of the antimicrobial, and the release of phage particles for a long time had been demonstrated, exhibiting higher healing of infected venous leg ulcers [36– 38, 96, 110]. The use of the PhagoBioDerm is promising for each remedy and prevention of microbial infections in wounds [36, 111]. Therapeutic bacteriophages, method of isolation, purification, and storage, units of phage, outcome of the bacteriophage therapy and reference are listed in **Table 1**.


**1. Introduction**

There is substantial knowledge on ancient games, especially on the use of board games in the ancient cultures of the Middle East (see for example: [1]), to the extent that for some of them, detailed rules for playing and general utilization are sufficiently well understood (Finkel 2007 [1], pag. 16–32), as is their role in social activities and cultural transmission [2,3]. However, investigations on ancient gaming materials in Europe are rather limited. Only in the last thirty years have several thematic exhibitions focused on the games in ancient times and the materials related to the games themselves [4–8].

The recent find of an unusual assemblage of small objects during the archaeological excavation at Villa del Foro (Alessandria, Italy) [9], possibly related to gaming practices in Pre-Roman cultures, has prompted an in depth characterization of the materials as an aid to the interpretation of their manufacturing and use [10,11]. The assemblage is composed of cubic dice, washer-like pieces, and small spheres. The archaeometric characterization of the objects is presented here, as well their interpretation based on the available knowledge of coeval similar objects.


**NEW TRENDS IN NUCLEAR SCIENCE**

Edited by **Nasser Sayed Awwad** and **Salem A. AlFaify**

#### **New Trends in Nuclear Science**

http://dx.doi.org/10.5772/intechopen.74762 Edited by Nasser Sayed Awwad and Salem A. AlFaify

#### **Contributors**

Andres Rodriguez-Hernandez, Armando Miguel Gomez-Torres, Edmundo del Valle Gallegos, Thomas W. Grimshaw, Olena L. Maslyanchuk, Stepan Melnychuk, Volodymyr Gnatyuk, Toru Aoki, Joji M. Otaki, Nasser S Awwad, Salem A. AlFaify

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New Trends in Nuclear Science Edited by Nasser Sayed Awwad and Salem A. AlFaify p. cm. Print ISBN 978-1-78984-656-0 Online ISBN 978-1-78984-657-7 eBook (PDF) ISBN 978-1-83881-806-7