**Author details**

Mohammad Sohidul Islam1 \*, Imam Muhyidiyn1 , Md. Rafiqul Islam2 , Md. Kamrul Hasan1 , ASM Golam Hafeez3 , Md. Moaz Hosen4 , Hirofumi Saneoka5 , Akihiro Ueda5 , Liyun Liu6 , Misbah Naz7 , Celaleddin Barutçular8 , Javeed Lone9 , Muhammad Ammar Raza9 , M. Kaium Chowdhury10, Ayman El Sabagh9,11\* and Murat Erman 9

1 Department of Agronomy, Hajee Mohammad Danesh Science and Technology University, Dinajpur, Bangladesh

2 Agronomy Division, Regional Agricultural Research Station, BARI, Pabna, Bangladesh

3 Department of Agricultural Finance, Bangladesh Agricultural University, Mymensingh, Bangladesh

4 Department of Agricultural Chemistry, Hajee Mohammad Danesh Science and Technology University, Dinajpur, Bangladesh

5 Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan

6 Department of Biotechnology, Osaka University, Suita, Osaka, Japan

7 Institute of Environment and Ecology, School of Environment and Safety Engineering, Jiangsu University, Zhenjiang, China

8 Faculty of Agriculture, Department of Field Crops, Çukurova University, Adana, Turkey

9 Faculty of Agriculture, Department of Field Crops, Siirt University, Siirt, Turkey

10 Agricultural Training Institute, Department of Agricultural Extension, Gaibandha, Bangladesh

11 Faculty of Agriculture, Department of Agronomy, Kafrelsheikh University, Kafrelsheikh, Egypt

\*Address all correspondence to<EMAIL_ADDRESS>and<EMAIL_ADDRESS>
© 2022 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.

*Soybean and Sustainable Agriculture for Food Security DOI: http://dx.doi.org/10.5772/intechopen.104129*


*Article* **Prognostic Effect of Preoperative Psoas Muscle Hounsfield Unit at Radical Cystectomy for Bladder Cancer**

**Yusuke Sugino 1 , Takeshi Sasaki 1 , Manabu Kato 1 , Satoru Masui 1 , Kouhei Nishikawa 1 , Takashi Okamoto 2 , Shinya Kajiwara 2 , Takuji Shibahara 2 , Takehisa Onishi 2 , Shiori Tanaka 3 , Hideki Kanda 3 , Hiroshi Matsuura 3 and Takahiro Inoue 1,\***

**Simple Summary:** Radical cystectomy (RC) is the standard treatment for patients with advanced bladder cancer. Since RC is a highly invasive procedure, it is necessary to carefully predict the prognosis before surgery and to determine the surgical indication. According to the results of the retrospective analysis of our 177 RC cases, we found the Hounsfield units of the psoas muscle at the third lumbar vertebral level to be a prognostic factor. Univariate and multivariate analyses revealed that age, sex, clinical T stage, and psoas muscle Hounsfield units were significant preoperative factors for overall survival. Furthermore, risk classification using these four factors was useful for predicting the prognosis of patients with RC.

**Abstract:** Radical cystectomy (RC) is the standard treatment for patients with advanced bladder cancer. Since RC is a highly invasive procedure, the surgical indications in an aging society must be carefully judged. In recent years, the concept of "frailty" has been attracting attention as a term used to describe fragility due to aging. We focused on the psoas muscle Hounsfield unit (PMHU) and analyzed its appropriateness as a prognostic factor together with other clinical factors in patients after RC. We retrospectively analyzed the preoperative prognostic factors in 177 patients with bladder cancer who underwent RC between 2008 and 2020. Preoperative non-contrast computed tomography axial image at the third lumbar vertebral level was used to measure the mean Hounsfield unit (HU) and cross-sectional area (mm2 ) of the psoas muscle. Univariate analysis showed significant differences in age, sex, clinical T stage, and PMHU. In multivariate analysis using the Cox proportional hazards model, age (hazard ratio (HR) = 1.734), sex (HR = 2.116), cT stage (HR = 1.665), and PMHU (HR = 1.758) were significant predictors for overall survival. Furthermore, using these four predictors, it was possible to stratify the prognosis of patients after RC. Finally, PMHU was useful as a simple and significant preoperative factor that correlated with prognosis after RC.

**Keywords:** bladder cancer; urothelial carcinoma; radical cystectomy; frailty; prognostic factor; psoas muscle; Hounsfield units

## **1. Introduction**

Radical cystectomy (RC) is the gold standard treatment for patients with muscle invasive bladder cancer, patients with selected T1 high-grade non-muscle invasive bladder cancer, and patients with carcinoma in situ resistant to Bacillus Calmette–Guérin treatment [1]. RC remains one of the most invasive urological procedures, and its surgical

**Citation:** Sugino, Y.; Sasaki, T.; Kato, M.; Masui, S.; Nishikawa, K.; Okamoto, T.; Kajiwara, S.; Shibahara, T.; Onishi, T.; Tanaka, S.; et al. Prognostic Effect of Preoperative Psoas Muscle Hounsfield Unit at Radical Cystectomy for Bladder Cancer. *Cancers* **2021**, *13*, 5629. https://doi.org/10.3390/ cancers13225629

Academic Editor: José I. López

Received: 4 October 2021 Accepted: 4 November 2021 Published: 10 November 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/).

indication needs to be carefully assessed in an aging society. According to the "Annual Report on the Aging Society 2020" from the Cabinet Office of Japan, the total population of Japan is 126.17 million as of 2019, of which 35.89 million are aged 65 years or older. Japan is facing an aging society ahead of the rest of the world. A systematic review has reported that perioperative mortality within 90 days after RC significantly increases in the elderly, and overall survival (OS) and cancer-specific survival (CSS) also decrease with age [2]. Aging is clearly a risk factor for RC. In recent years, the concept of "frailty" has been attracting attention as a term that expresses fragility due to aging [3]. If the prognosis can be predicted more accurately by assessing not only the clinical stage and age of the patient but also malnutrition and muscle weakness associated with decreased physical activity, it can help in deciding whether to perform surgery. Although few established definitions with regard to the elderly or frailty have been reported, there have been some attempts to define them with various assessments [3–5]. Several reports linking frailty and sarcopenia to predict prognosis in patients with bladder cancer have been reported [3,6–10]. As an indicator that may objectively represent frailty, we focused on the psoas muscle Hounsfield unit (PMHU), which is defined as the mean computed tomographic attenuation value of the psoas muscle. The main aim of this study is to assess the utility of PMHU as a preoperative prognostic marker in patients receiving RC for bladder cancer.

#### **2. Materials and Methods**

#### *2.1. Study Design and Patients*

We retrospectively reviewed the records of consecutive patients who underwent open radical cystectomy (ORC), laparoscopic radical cystectomy (LRC), or robot-assisted laparoscopic radical cystectomy (RARC) for bladder cancer at Mie University Hospital, Ise Red Cross Hospital, and Mie Prefectural General Medical Center. A total of 177 patients (113 patients at Mie University Hospital, 42 patients at Ise Red Cross Hospital, and 23 patients at Mie Prefectural General Medical Center) were enrolled.

#### *2.2. Image Analyses*

Abdominal non-contrast computed tomography (NCCT) images (1–5 mm-thick slices) taken within 3 months before RC were used to measure the imaging factors related to the psoas muscle. Four urologists (Y.S., S.K., T.O., and S.T.) freehand outlined each psoas muscle at the third lumbar vertebral level in the axial NCCT image (Figure 1).

The right and left total areas were used for the psoas muscle area (PMA) (mm2 ). The mean value of the mean computed tomographic attenuation value of the right and left psoas muscle was used for the PMHU (HU). The psoas mass index (PMI) (cm2/m2 ) was calculated by normalizing the cross-sectional area by height [11].

**Figure 1.** Measurement of the psoas muscle area (PMA) and the mean psoas muscle Hounsfield unit (PMHU) on the preoperative axial non-contrast computed tomography image at the third lumbar vertebral level.

#### *2.3. Statistical Analyses*

All statistical analyses were performed using EZR version 1.33 [12]. Student's *t*-test or Mann–Whitney U test was performed for comparisons between groups of continuous variables. Categorical variables were analyzed using the chi-squared test or Fisher's exact test. The survival curve was estimated using the Kaplan–Meier method and analyzed using the log-rank test. Cox proportional hazards analysis was used to calculate the hazard ratio (HR) and 95% confidence interval (CI) in univariate and multivariate analyses. In all tests, *p* < 0.05 was considered statistically significant.

#### **3. Results**

Of the 177 patients, 26 (14.7%) were women and 151 (85.3%) were men. The median age was 70 (quartile: 66–76) years, and the median follow-up period was 1002 (quartile: 358–1989) days. The 5-year OS, CSS, and recurrence-free survival (RFS) rates were 59.7%, 71.3%, and 48.7%, respectively. The median OS, CSS, and RFS were 8.86 years (95% CI, 5.00 years to not reached), not reached (95% CI, not reached to not reached), and 4.70 years (95% CI, 2.66 to 9.24 years), respectively. Platinum-based neoadjuvant and adjuvant chemotherapy were performed in 75 (42.4%) and 22 (12.4%) patients, respectively. The surgical procedures were ORC, LRC, and RARC in 119 (67.2%), 38 (21.5%), and 20 (11.3%) patients, respectively. There were 114 (64.4%) and 29 (16.4%) perioperative complications of Clavien–Dindo grade ≥2 and ≥3, respectively. The median length of hospital stay after RC was 26 (quartile: 22–41) days. The histopathological diagnosis after RC was urothelial carcinoma in 138 (77.8%) patients, and some histological variants were found in 39 (22.0%) patients. There were 71 (40.1%) patients with pT ≥3, 33 (18.6%) patients with pN positivity, and 89 (50.3%) patients with LVI positivity, all of which were significant prognostic factors for OS (*p* < 0.01, log-rank test). Body mass index, PMI, PMA, and PMHU were significantly different between men and women (Table 1).

**Table 1.** Patient characteristics.

IQR = interquartile range, BMI = body mass index, ASA-PS; American Society of Anesthesiologists physical status, NMIBC = non-muscle invasive bladder cancer, PMA = psoas muscle area, PMI = psoas mass index, PMHU = psoas muscle Hounsfield unit.

> For variables related to the psoas muscle, it was considered inappropriate to apply the same cutoff value for men and women; thus, the lower limit of the interquartile range for each sex (25 percentile) was used as the cutoff value.

The results of Cox proportional hazards analysis for OS were shown in Table 2.

Univariate analysis showed significant differences in age, sex, cT stage, and PMHU (*p* < 0.05). The median OS stratified by PMHU alone in the not-low and low PMHU groups were 9.24 years (95% CI, 6.40 years to not reached) and 2.78 years (2.06 years to not reached), respectively, and there was a significant difference among them (*p* = 0.014). Multivariate analysis using the four factors that were significantly different in the univariate analysis showed significant differences in all factors (*p* < 0.05).

We focused on these four factors to develop a risk classification for predicting OS in patients with bladder cancer after RC (Table 3). The Kaplan–Meier curve for OS according to the number of risks was shown in Figure 2.

**Table 2.** Cox proportional hazards analysis of overall survival in patients undergoing radical cystectomy.

**Table 2.** *Cont.*

HR = hazard ratio, CI = confidence interval, ASA-PS = American Society of Anesthesiologists physical status, BMI = body mass index, PMA = psoas muscle area, PMI = psoas mass index, PMHU = psoas muscle Hounsfield unit.

**Table 3.** Risk factors and risk category.

PMHU = psoas muscle Hounsfield unit.

Based on this result, we defined a group with one or fewer risk factors as a low-risk group, a group with two risk factors as an intermediate-risk group, and a group with three or more risk factors as a high-risk group (Table 3). The Kaplan–Meier curve and HR for each risk category were shown in Figure 3 and Table 4, respectively.

The median OS by our risk category in the low-risk, intermediate-risk, and high-risk groups (Table 3) were not reached (95% CI, 8.86 years to not reached), 6.40 years (95% CI, 2.67 years to not reached), and 2.06 years (95% CI, 0.94 to 2.78 years), respectively (*p* < 0.01). There were no significant differences among the risk groups in terms of postoperative hospital stay and the incidence of complications.

**Figure 2.** Kaplan–Meier curves for overall survival according to the number of risks.

**Figure 3.** Kaplan–Meier curves for overall survival according to risk category.

**Table 4.** Hazard ratio for each risk category.

HR = hazard ratio, CI = confidence interval.

#### **4. Discussion**

In the present study, we investigated the significance of preoperative PMHU on the prognosis after RC in patients with bladder cancer. We showed that PMHU is a new prognostic marker along with sex, age, and cT stage, and that these predictors could be used to preoperatively stratify the prognosis of patients with bladder cancer after RC.

In recent years, medical technology innovations have led to minimally invasive surgery, but RC remains highly invasive because of the long operation time and high incidence of perioperative complication rates [2]. Elderly people had a higher 90-day mortality rate and more early complications after RC than younger people [2], and it is often discussed whether RC should be performed, especially for elderly patients.

In order to judge the indication for RC, it is required not only to evaluate the surgical tolerance such as cardiac function and respiratory function, but also to predict the postoperative prognosis to some extent. LVI and pN positivity and pT3 or higher grade have already been reported as postoperative factors related to prognosis [13], and similar results were obtained with our cases. However, pathological factors are the information that can only be known after RC. There are few reports on prognostic markers that are useful in deciding whether or not to perform RC itself.

In an aging society, the concept of frailty is drawing attention. Especially in the elderly, comprehensive assessment of patients' frailty as well as their age may be useful for treating diseases and improving their quality of life [14,15]. Diagnosis of frailty requires the measurement of grip strength and walking speed [4,5], but there are few facilities that can be incorporated into the daily practice of treating patients with urological malignancies. In particular, it is not desirable to impose a heavy preoperative evaluation on patients with their malignancies.

Regarding the assessment of frailty, NCCT images are easy to acquire and non-invasive. PMA [16], psoas muscle volume (PMV) [9,17,18], PMI [9,11], mean PMHU [19], skeletal muscle index (SMI) [6,8,20], intramuscular adipose tissue content (IMAC) [21], and so on, have been reported as representative imaging factors for frailty. According to a systematic review by Cao et al., SMI, PMI, muscle attenuation, and IMAC were useful for assessing the risk of postoperative complications as NCCT-assessed sarcopenia indices [22]. Analysis of our data did not reveal significant results for PMA and PMI, but PMHU correlated with the prognosis of patients with bladder cancer after RC.

PMHU can be measured very simply and easily. No special training or software is required. NCCT images are always acquired in patients before RC, without the burden of adding new special tests to the patients. Low PMHU reflects skeletal muscle fat infiltration and may indirectly be used to assess frailty [23]. Increase in fat infiltration within skeletal muscle might precede loss of skeletal muscle volume during the progression of cancer cachexia [24].

PMHU is a factor that reflects muscle quality, while PMA and PMI are factors that reflect muscle mass [20,22]. In our data, this may be one of the reasons why only PMHU, not PMA and PMI, showed a significant correlation with OS. Assessing psoas muscle mass with an NCCT image at the L3 level is very simple but may not necessarily reflect systemic skeletal muscle mass [25]. PMV and SMI may reflect systemic muscle mass better than PMA and PMI, but at the expense of ease of measurement [18]. We consider PMHU to be a more practical predictor because of its ease of measurement and its accuracy for prognosis.

Frailty was also evaluated as a risk factor for perioperative complications in patients with bladder cancer [9,26]. Prediction of patients' prognosis preoperatively may avoid surgical invasive procedures which would cause more harm than benefit in patients. According to our results, the median OS of high-risk patients who have three or more preoperative poor prognosis factors defined by age, sex, cT stage, and PMHU was only 2.06 years. Although our data would not give definitive prediction of perioperative complication, high-risk patients with poor prognosis in our risk classification might not recommend RC. Bladder sparing therapy combined with transurethral resection of the bladder tumor, chemotherapy, and radiation therapy are controversial, but they may be a good treatment option for patients with an apparently poor prognosis [9,27].

By preoperatively diagnosing frailty, it may be possible to improve the prognosis of cancer patients if interventions such as exercise therapy and nutritional guidance can be performed earlier [17,28]. Exercise therapy and essential amino acid supplement drinks have been shown to be useful in recovery from serious illnesses [29] and vitamin D supplementation was useful in improving sarcopenia in the elderly [30]. It goes without saying that treatment of the bladder cancer itself is important for improving the OS. However, in an aging society, we must understand the physical function and nutritional status of each patient before intervening with diverse treatments. To that end, the role of the rehabilitation team, which includes registered dietitians and physiotherapists, is also important, and more than ever it is necessary to deepen cooperation within the team.

There are several limitations of our study. The present study is a small retrospective study. Our results need to be prospectively validated in a larger cohort. In addition, the subjects of this study were limited to the Japanese population, and there is room for consideration of differences between races, especially regarding the cutoff value. Furthermore, the present study did not directly investigate the relationship between PMHU and frailty. In the future, the direct relationship between the already reported diagnostic factors of frailty and PMHU must be investigated [4,5]. In addition we believe that it should be examined in more detail whether perioperative nutrition therapy and physiotherapy for patients with low PMHU can improve the bladder cancer patients' survival and quality of life.

#### **5. Conclusions**

PMHU was a preoperative predictor of prognosis in patients with bladder cancer who were about to undergo RC. The prognosis of patients could be stratified before RC using age, sex, cT stage, and PMHU. Not only can PMHU be measured without burdening patients and clinicians, but also this risk classification helps determine whether to perform RC in patients with bladder cancer before surgery.

**Author Contributions:** Conceptualization, Y.S. and T.I.; data curation, Y.S., T.O. (Takashi Okamoto), S.K. and S.T.; formal analysis, Y.S.; funding acquisition, T.I.; investigation, Y.S.; methodology, Y.S. and T.I.; project administration, Y.S. and T.I.; supervision, T.S. (Takuji Shibahara), M.K., S.M., K.N., T.S. (Takeshi Sasaki), T.O. (Takehisa Onishi), H.K., H.M. and T.I.; writing—original draft, Y.S. and T.I.; writing—review and editing, Y.S., T.S. (Takeshi Sasaki), K.N. and T.I. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was financially supported by Grants-in-Aid from the Ministry of Education for Science and Culture of Japan (21H03066).

**Institutional Review Board Statement:** The study was conducted according to the guidelines of the Declaration of Helsinki, and approved by the Institutional Review Board of Mie university (approval code H2020-110).

**Informed Consent Statement:** Informed consent was obtained in the form of opt-out on the web-site. Those who opted out were excluded.

**Data Availability Statement:** The data are available to other researchers on written request to the corresponding author.

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

## **References**


**Acknowledgements**

The authors would like to thank the patients and their family. We are grateful to all of the staff of the Department of Medical Genetics of the National Institute of Health for their continuous support.

**137**

**Author details**

Rabat, Morocco

Yahya Benbouchta1,2\*, Ahmed Afailal Tribak2

provided the original work is properly cited.

\*Address all correspondence to<EMAIL_ADDRESS>
and Khalid Sadki2

1 Department of Medical Genetics, National Institute of Health, Rabat, Morocco

2 Laboratory of Human Pathology, Faculty of Sciences, Mohammed V University in

© 2021 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,

*Research of the Philadelphia Chromosome in Chronic Myeloid Leukemia: Diagnostic…*

*DOI: http://dx.doi.org/10.5772/intechopen.95865*


**1. Introduction**

With the rapid development of expressway construction, in China, construction on soft ground is sharply increasing, such as Shen-Jia-Hu Expressway that passes through soft soil [1,2]. Owing to shortened construction periods and to the rheological properties of soft soil, among other reasons, the embankment after settlement of many highways opened abroad is too high, which does not meet relevant regulatory requirements (i.e., post-construction should be less than 30.0 cm) [3]. The post-construction settlement of expressways has become a major type of expressway damage, which will not only seriously affect the vehicle's road speed, traffic safety, and driving comfort, but also seriously affect the stability and safety of the highway itself [4–6].

In order to reduce post-construction settlement, the embankment is replaced with light soil to reduce the overburden load and control the settlement [7,8]. At present, the widely used light soils mainly include EPS beads-mixed lightweight soil, EPS block, and foamed cement banking, which include good integrity, light mass, and convenient construction. The lightweight soil's cohesion, global strength, bulk density, and other parameters can be adjusted by adjusting the output of cement and foam [9]. The advantages and disadvantages of various methods are shown in Table 1. Foamed cement banking research is already well underway in numerous countries [10–12], and some results have been achieved in practice. Compared with other materials, the FCB has a shorter construction period, lower curing time, and higher construction quality, thus it has broad application prospects [13,14]. As FCB's bulk density is only conventional soil bulk density of 1/4 to 1/8, its use as a replacement of embankment material [15–17], can not only reduce the base load pressure, but can also reduce the total settlement and differential settlement [18]. Replacing the undisturbed soil with lightweight soil to process the post-construction settlement of

**Citation:** Wu, Y.; Liu, H.; Liu, J. Use of Foamed Cement Banking for Reducing Expressways Embankment Settlement. *Appl. Sci.* **2021**, *11*, 11959. https://doi.org/10.3390/ app112411959

Academic Editors: Daniel Dias and Bing Bai

Received: 14 October 2021 Accepted: 13 December 2021 Published: 15 December 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/).

expressway under traffic control seriously affected highway traffic operations. Especially, there are no closed roads (ramps) during construction, the lightweight soil is being put down to achieve subgrade compactness, that causes huge economic losses due to the road closure.

**Table 1.** Comparison of different lightweight fills.

In this paper, foamed cement replacement is carried out on both sides of the embankment, which does not affect the normal traffic operation during replacement construction, its use is targeted and flexible, and only small settlement occurs after improvement. Combined with Shen-Jia-Hu EK0 + 323 highway section, this paper verifies the advantages of FCB in dealing with embankment settlement without road closure. Through the analysis of dynamic monitoring data of Shen-Jia-Hu expressway's subgrade settlement, and according to the proportional relationship between settlement and load, the calculation method of embankment replacement thickness is proposed, which can be applied to complex construction processes, this work can thus provide a reference for similar future projects.


**Centralized Distributed Parameter Bioprocess Identification and I-Term Control Using Recurrent Neural Network Model**

Ieroham Baruch1, Eloy Echeverria-Saldierna1 and Rosalba Galvan-Guerra2 *1CINVESTAV-IPN, Mexico City, Department of Automatic Control, 2ESIMEZ-IPN, Mexico City, Department of Control and Automation Engineering, Mexico*


2.2.1. Airborne Multi/Hyperspectral Imaging

Imaging techniques can be deployed above the water's surface using multispectral/hyperspectral imagers. These surveys primarily look at coral distribution. However, they are limited by low spectral and spatial resolution and are only able to distinguish between coral, algae, and sand [61]. Aerial surveys can be undertaken using light aircraft or helicopters flying at an altitude of approximately 150 m. Aircraft and satellites can be equipped with multispectral and hyperspectral imagers. Aircraft are able to use benthic reflectance signatures to map the composition and condition of shallow water ecosystems in higher spatial resolution than their satellite counterparts, albeit at the cost of lower spatial scale [78]. In bleaching surveys, each reef is typically assigned a number from zero to four, these categories are associated with bleaching severity. The category classifications are as follows: CAT 0, <1% of corals bleached; CAT 1, 1–10%; CAT 2, 10–30%; CAT 3, 30–60%; and CAT 4, >60% of corals bleached [79]. Correction algorithms are required to account for loss of light through factors such as atmospheric scattering and the attenuation coefficient of

water. As such, airborne surveys still require underwater ground-truthing to compare and validate these correction procedures [80].

The spatial resolution and cost of remote hyperspectral observations can be further improved by using unmanned aerial vehicles (UAVs). Lightweight hyperspectral cameras deployed on UAVs typically produce images with a spatial resolution of around 15 cm/pixel, allowing for the identification and monitoring of individual corals [81]. In a set period, this method can cover larger areas than diver or UUV solutions. Compared to manned aircraft, UAVs achieve higher resolution primarily due to the lower flight altitude (30–100 m), but at a smaller spatial scale. This technique allows for rapid data of areas of reef for preliminary assessments. For example, a 2017 study by Queensland University of Technology demonstrated that a UAV could photograph 40 hectares of coral reef in approximately 30 min to enable the study of coral bleaching [82].


**3. Newer innovation in preoperative planning**

Complex primary hip cases involving dysplasia at either side of the joint, trauma cases with fractures requiring arthroplasty, ankylosing spondylitis, protrusio cup and revision hip cases are a big challenge for arthroplasty surgeons. Rapid prototyping (RP) is a new concept adopted from industrial designing. This involves laying down series of additional layers of a material to regenerate a 3D model. Computer aided designing (CAD) program enables rapid production of a component with super accuracy [22]. This model is adopted in medical specialties including orthopedics to develop accurate replica of a body part in cross-section using CT scan as an input source. They are further printed using layered material to generate a 3D-printing model. This rapid prototype model provides a unique opportunity in preoperative planning, in terms of understanding deformity pattern, providing intraoperative referencing and surgical simulation. This further helps an arthroplasty surgeon for inventory planning as they can order necessary implants to make their availability on the day of surgery. This will save time during surgery and minimize on table bleeding, infection rate and thereby patient morbidity.

#### **3.1. Customized instruments and implants**

With advancement in the modern day technology, patient specific instruments can be obtained by using rapid prototyping [23]. This will aid in complex cases and will aid in improvement in operative results. In future more customized implants will be developed to use for the individual case demand that will fit for the purpose and will have better survival outcome for our patients by improving joint kinematics.

[2] Capello WN. Preoperative planning of total hip arthroplasty. Instructional Course Lectures.

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[7] Noble PC, Alexander JW, Lindahl LJ, et al. The anatomic basis of femoral component

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## **4. Conclusion**

Preoperative planning is an important step in the actual delivery of joint replacement as it allows the patient to go through a comprehensive assessment and preparation for undertaking joint replacement in a schematic fashion. This begins with a thorough clinical assessment by their operating surgeon and a series of investigations followed by actual planning of their hip joint replacement, utilizing template on their standardized radiographs. Templating process allows assessment of their anatomical landmarks to mark as reference points while implanting prosthesis with correct depth. This will allow the surgeons to restore hip biomechanics and thereby improving post-surgical outcomes. This will further allow anticipating difficulties and pitfalls prior to surgery.

Some surgeons do not like to proceed with this important step of templating prior to their joint replacement surgeries. However, unless it is done systematically, it might be difficult, even for the experience hip surgeons to identify those hips, which will definitely benefit from a proper anatomical and mechanical assessment. Moreover, these less planed cases without templating are at increase risk to suffer inadequate hip biomechanics and higher complication rates including trendelenburg gait, joint dislocation, significant leg length discrepancy, peri prosthetic fracture and trochanteric pain. It has been proven to have similar efficacy of preoperative templating by the junior surgeons in training as their senior counter parts [11]. Thus it makes it a legitimate cause for carrying out this vital process of templating of the hip joint prior to actual implantation of the prosthesis. In crux this will improve the long-term outcome and patient satisfaction in both subjective and objective manner [3, 4].


**1.2 Objectives of the study**

This study is based on a review of available literature for the Prairie Region and other similar parts of the world. Its major objective is to review impacts of climate change on agriculture in the Prairie Region in the context of resiliency. Both direct and indirect impacts are included in the review along with adaptation measures that could be adopted to reduce the negative impacts of climate change and to create resiliency.


**1. Introduction**

At the beginning of a transition in shear flow, a large number of vortex structures are formed. The formation mechanism and dynamic characteristics of vortex structures are still key issues in fluid mechanics research.

Lee presented direct comparisons of experimental results on transitions in wall-bound flows obtained by flow visualizations, hot-film measurement, and Particle Image Velocimetry (PIV), along with a brief mention of relevant theoretical progresses, based on a critical review of about 120 selected publications. Despite the somewhat different initial disturbance conditions used in the experiments, the flow structures were found to be practically the same [1]. Sharma presented a new theory of coherent structures in wall turbulence. The theory is the first to predict packets of hairpin vortices and other structures in turbulence and their dynamics, based on an analysis of the Navier–Stokes equations, under an assumption of a turbulent mean profile [2]. Wedin studied finite-amplitude coherent structures with a reflection symmetry in the span-wise direction of a parallel boundary layer flow; some states computed displayed a span-wise spacing between streaks of the same length scale as turbulence flow structures observed in experiments [3]. Wu presented a mathematical theory to describe the nonlinear dynamics of coherent structures. The formulation was based on a triple decomposition of the instantaneous flow into a mean field, coherent fluctuations, and small-scale turbulence, but with the mean-flow distortion induced by nonlinear interactions of coherent fluctuations being treated as part of the organized motion [4]. Mcmullan implemented large eddy simulations of the plane mixing layer for the purpose of reducing the stream-wise vortex structure that may exist in these flows. Both an initially laminar and initially turbulent mixing layer were considered in this study. The initially laminar flow originated from Blasius profiles with a white noise fluctuation environment, whilst the initially turbulent flow had an inflow condition obtained from an inflow turbulence generation method. Flow visualization images demonstrated that both mixing layers contained organized turbulent coherent structures, and that the structures contained rows of stream-wise vortices distributed across the span of the mixing layer [5]. Wall studied three spatially extended traveling wave exact coherent states, together with one span-wise localized state for channel flow. Two of the extended flows were derived by the homotopy method from solutions. Both these flows were asymmetric with respect to the channel center plane, and featured streaky structures in stream-wise velocity flanked by staggered vortical structures; one of these flows featured two streak/vortex systems per span-wise wavelength [6]. Kang studied the direct numerical simulation data of a wave packet in laminar turbulent transition in a Blasius boundary layer. The decomposition of this wave packet into a set of modes could be achieved in a wide variety of ways [7]. Shinneeb experimentally studied the turbulent wake generated by a vertical sharp-edged flat plate suspended in a shallow channel flow with a gap near the bed. Two different gap heights were studied which were compared with the no-gap flow case. The Reynolds number based on the water depth was 45,000. Extensive measurements of the flow field in the vertical and horizontal planes were made using a PIV system. The large vortices were exposed by analyzing the PIV velocity fields using the proper orthogonal decomposition method [8]. Lemarechal experimentally investigated the laminar turbulent transition of a Blasius boundary layer-like flow at the Institute of Aerodynamics and Gas Dynamics, University of Stuttgart. The late stage of controlled transition with K-type breakdown was investigated with the temperature-sensitive paint (TSP) method on the flat-plate surface. The test conditions enabled the TSP method to resolve the complete transition process temporally and spatially. Therefore, it was possible to detect the coherent structures occurring in the late stage of laminar–turbulent transition from the visualizations on the flat-plate surface, namely, Λ and Ω vortices [9]. The effects of isolated, cylindrical roughness elements on laminar–turbulent transition in a flat-plate boundary layer were investigated in a laminar water channel. Most predictions by global linear stability theory could be confirmed, but additional observations in the physical flow demonstrated that not all features could be captured adequately by global linear stability theory [10].

There are many kinds of small disturbance models for boundary layer transition, such as combination Tollmier–Schlichting(T–S) waves, multi-eddy structures which satisfy continuity equation, slot jets, and so on. The initial disturbance sources of other physical models except slot jets are still not clear. In this paper, vortex structures induced by local instantaneous small wall vibration combinations similar to the real physical mechanism are adopted, and the internal mechanisms of the influence of different disturbance combinations on the flow stability are analyzed.

To perform approximate simulations of the wall local forced vibration, an initial disturbance was set in the form of local single-period micro-vibration at the bottom of the wall of *y* = 0. However, the influence of physical deformation on the mesh was neglected since it is outside of the scope of this paper. Two disturbance models were implemented, namely, the positive–negative (P–N) model and the negative–positive (N–P) model. The P–N model is defined as follows: the normal disturbance velocity at mesh points in the circle region, ) (*x* − 10.5) 2 + *z*2 < 2 is supposed to be *v* = 0.02 sin(2π · *t*/15), where 0 ≤ *t* ≤ 15, and that in the circle region, ) (*x* − 14.7) 2 + *z*2 < 2, is supposed to be *v* = −0.02 sin(2π·*t*/15), where 0 ≤ *t* ≤ 15. Similarly, the N–P model is defined as follows: the normal disturbance velocity at mesh points in the circle region, ) (*x* − 10.5) 2 + *z*2 < 2, is supposed to be *v* = −0.02 sin(2π · *t*/15), where 0 ≤ *t* ≤ 15, and that in the circle region, ) (*x* − 14.7) 2 + *z*2 < 2, is supposed to be *v* = 0.02 sin(2π · *t*/15), where 0 ≤ *t* ≤ 15. The amplitude of the small disturbance velocity is commonly chosen to be about 1% of the maximum mean basic flow velocity. A relatively small amplitude of the disturbance velocity can lead to a relatively long time of disturbance evolution. The computational domain and initial disturbance location are shown in Figure 1.

**Figure 1.** Distribution of initial disturbance at the wall.

#### **2. Governing Equations and Numerical Method**


**Abstract**

This paper introduces a recent innovation survey, the first of its kind in the Digital Age. With coverage of 300 large firms, sampled to be representative of corporate innovation in eight countries, the survey provides a unique look at how innovation, particularly digital innovation, is being sourced by firms around the world. We find that open innovation at these companies is pervasive, but also recent. Only in the 2010s have many firms started innovating with external partners like universities, third-party experts, startups, or crowd. Overwhelmingly, firms use these new external innovation sources for digital technologies where they have internal capability shortfalls. Despite the remarkable growth in the use of external innovation sources, internal innovation sources remain more important for companies. These internal sources also produce the projects most likely to provide a competitive advantage.

**Keywords:** innovation sources, capabilities, digital, open innovation, competitive advantage


**4.6 Role of legume vegetation on enhancing soil microbial biomass**

Soil microorganisms have a necessary link between plant productiveness and soil nutrient availability as they are indirectly directly engaged in the nutrients cycling through the conversion of inorganic and organic types of nutrients [31]. Legumes are one of the necessary components to increase soil microbial biomass in soils. Legumes play a necessary function in SMB and energetic key strategies such as nutrient cycling and soil organic matter decomposition and, thus, improve crop productiveness and soil sustainability [32]. Some microorganisms which interact physically with leguminous vegetation in the rhizospheric zone can also enhance crop productivity positively by enhancing plant increase and development [33].


Contents

Preface

*Forensic Analysis - Scientific and Medical Techniques and Evidence under the Microscope*  is an edited collection of cutting-edge analyses of diverse contemporary aspects of forensic science and forensic medicine. It is a truly international collection. It contains eleven chapters from scholars in Australia, China, Egypt, France, India, Iraq, Italy, the Netherlands, Russia and Saudi Arabia. The aim of the collection is to provide information about the parameters of expertise in relation to a number of areas that are being utilised as a part of criminal investigations and that are coming before courts

Key aspects of the evaluation of forensic science and forensic medicine are the concepts of reliability and validity. While validity focuses upon the accuracy of a measure, in forensic matters reliability tends to be the more important issue in terms of the value of expert evidence. Evaluation of the reliability of expert opinion evidence is controversial in all countries and there are diverse yardsticks by which it can be measured, including formal recourse to factors such as falsifiability, error rate, extent of publication in recognised, peer-reviewed journals and reputation amongst colleagues in the same field. When areas are "novel" in the sense of still emerging from the iconoclastic or emerging toward the generally accepted by reference to objective criteria, there can be a tension between the actual techniques and the theories underlying them and the prejudicial effect that they may exert on courts (especially jurors) called upon to evaluate them. This can be so for countries that utilise admissibility criteria for such evidence but also for countries that focus upon the need to determine the probative value of such evidence.

In all such instances, there is a need for scientific and medical rigor with the employment of standardised methods, criteria for interpretation and retention of primary samples for re-testing as required. The caliber of those who undertake the forensic work is critical, as is the quality of the testing facilities, and adherence to ethical probity in disclosure and interpretation of results that may be other than criminal investigators are hoping for. There is always a need for transparency of processes and candid acknowledgment of the status of techniques and theories that as yet may not have fully fledged statistical bases enabling definitive interpretation of test results. In such scenarios courts and tribunals need to exercise circumspection in the reliance that they place upon such evidence, ensuring that witnesses giving evidence about such matters are made accountable for the opinions that they express. This highlights the need for legal practitioners to make themselves sufficiently familiar with the controversies about and limitations in scientific and medical techniques to be able to ask probing questions that expose

The book begins with a review by Freckelton (Chapter 1) of the controversial and emerging area of **forensic gait analysis evidence**, which is given by practitioners from a number of disciplines, including podiatry, photogrammetry, biomechanics and anatomy, and has been the subject of diverse judicial decisions about admissibility in Canada, the United

**The Book**

internationally or will soon do so.

**Reliability and Probative Value**

parameters of expertise and accuracy.

**The Chapters**


**Author details**

Dominique Amy Breast Center, Aix-en-Provence, France

\*Address all correspondence to<EMAIL_ADDRESS>
© 2022 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.


**4. Conclusions**

In this chapter, we provide guidelines for the design of novel SIW filters based on the alternation of SIW sections with reduced (perforated) or increased (periodically loaded with metallic cylinders) effective permittivity with ordinary SIW sections, making use of the impedance inverter model. Examples of several SIW filter configurations show that this solution can lead to the design of compact filters with good performance and low sensitivity to fabrication inaccuracies.


**14. Excessive day time sleepiness**

Excessive day time sleepiness (EDS) has been described in dialysis patients. Seventy-seven percent of patients on CAPD reported taking day time naps and 51% reported falling asleep unintentionally (46). The **Multiple Sleep Latency Test** (MSLT) is a sleep disorder diagnostic tool. It is used to measure the time elapsed from the start of a daytime nap period to the first signs of sleep, called **sleep latency**. The test is based on the idea that the sleepier people are, the faster they will fall asleep. The test consists of four or five 20-minute nap opportunities that are scheduled about two hours apart. The test is often performed after an overnight sleep study. During the test, data such as the patient's, EEG, muscle activity, and eye movements are monitored and recorded. The entire test normally takes about 7 hours.In one study, 44 HD patients were studied. Potential subjects with other major chronic conditions or those with medications known to have CNS effects were excluded from the study. In addition, to exclude those with obvious causes of EDS, subjects with a history suggestive of SAS, RLS and PLMD were also excluded. All subjects underwent polysomnography along with MSLT. One third of patients of the subjects had MSLT scores consistent with abnormal sleepiness (mean sleep latency <8min). High AHI was significantly associated with lower MSLT score, but explained only 10% of the variance in MSLT score, suggesting that

Sleep Disorders Associated with Chronic Kidney Disease 395

Day time sleepiness is common in patients with ESRD and patients with CKD not on

Sleep disorders have negative impacts on overall quality of life in patients with kidney

**Blood Urea Nitrogen** (BUN) is the blood test used to measure nitrogen in the form of Urea, which is the by product from protein metabolism produced in liver and removed by kidney **Dialysate**-the fluid used in dialysis, typically with a lower solute concentration than the

**Hemodialysis**(HD)-a process of removal of fluid and solutes through a semi-permeable membrane into dialysate by passing the blood through an artificial kidney. Hemodialysis is most commonly delivered to patients three times a week for three to four hours (Conventional Hemodialysis-CHD), but may also be given more slowly across the day or

**Nocturnal Hemodialysis** (NHD). Nocturnal hemodialysis or nightly hemodialysis is a form of hemodialysis which is done at home by the patient or a family member when the patient is sleeping at night. Most patients dialyze five to seven nights a week, anywhere from six

**Peritoneal Dialysis** (PD)-the process of removal of fluid and wastes from the body using the

**Continuous Ambulatory Peritoneal Dialysis** (CAPD)-continuous dialysis process that involves infusion of fluid into peritoneum, a prolonged dwell period for dialysis and

**Kt/V** is a way of measuring dialysis adequacy. Kt/V is defined as the dialyzer clearance of urea (**K**, obtained from the manufacturer in mL/min, and periodically measured and verified by the dialysis team) multiplied by the duration of the dialysis treatment (**t**, in minutes) divided by the volume of distribution of urea in the body (**V**, in mL), which is

[1] Walker S, Fine A, Kryger MH. Sleep complaints are common in a dialysis unit. Am J

[2] Pressman MR, Benz RL. High incidence of sleep disorders in end stage renal disease.

[3] Jung, HH, Han, H & Lee, JH: sleep apnea, Coronary artery disease, and antioxidant

[4] Zoccali, C, Mallamci, F, Tripepi, G & Benedetto, FA: Autonomic neuropathy is linked to

nocturnal hypoxemia and to concentric hypertrophy and remodelling in dialysis

status in hemodialysis patients, Am J kidney Dis, 45:875-82, 2005

patients, Nephrol Dial Transplant, 16:70-7, 200

semi-permeable membrane of the peritoneum for the diffusion and osmosis,

drainage. The procedure typically involves four exchanges of fluid daily.

diseases and may affect rehabilitative potential of treatment.

blood, into which metabolic waste and excess electrolytes diffuse.

**16. Glossary of dialysis-related terms**

night (Nocturnal Hemodialysis-NHD).

to12 hours, on average for eight hours.

approximately equal to the total body water.

Kidney Dis 1995; 26(5): 751±756

Sleep Research 1995; 24: 417.

**17. References**

dialysis.

additional factors play an important role in the expression of day time sleepiness in this group (65).

Benz etal reported the effects of hematocrit normalization with recombinant erythropoietin on the sleep of 10 HD patients (44). All subjects underwent an initial nocturnal polysomnogram, with seven completing a 40 minutes MWT the next day. Tests were repeated after normalization of hematocrit. Treatment resulted in a significant reduction of nocturnal periodic limb movements and improvement on the MWT.

SAS, RLS and PLMD are prevalent in patients with advanced kidney disease and could explain EDS, but some studies suggested that other factors related to renal disease or its treatment may contribute to EDS (52, 53).

Mild elevations of BUN and creatinine in renal failure patients have been associated with increased slow wave activity in the waking EEG and abnormalities in cognitive function, which may explain the susceptibility of patients with advanced renal disease to sleepiness (54). Elevation of parathyroid hormone has been associated with increased waking EEG slow wave activity in uremic animals and stable dialysis patient (55). The metabolites of creatinine may inhibit GABA responses (in mouse neurons) and may interfere with neurotransmissions necessary for sleep to occur. These changes may destabilize the wakeful state by increasing day time sleepiness propensity and decreasing nocturnal sleep (56).

Treatment with dialysis may also predispose patients to sleepiness. Abnormal production of interleukin-1, TNF-alpha, factor S can increase somnolence (57, 58). Rapid removal of these sleep inducing substances has also been postulated as the cause for fragmented nocturnal sleep and resulting day time sleepiness and fatigue in one study on patients on CAPD (59). Dialysis also results in rapid change in electrolytes, acid base balance and serum osmolarity which may decrease arousal and alertness (60). Treatment with dialysis may also disrupt the circadian pattern sleepiness due to inappropriately timed elevation of serum melatonin in response to the hemoconcentration (61) or from change in rhythm of body temperature (62). Medications such as antihypertensive and antidepressants may also contribute to the EDS in CKD patients.


**PRACTICAL APPLICATIONS IN BIOMEDICAL ENGINEERING**

Edited by **Adriano O. Andrade, Adriano Alves Pereira, Eduardo L. M. Naves**  and **Alcimar B. Soares**

http://dx.doi.org/10.5772/3331 Edited by Adriano O. Andrade, Adriano Alves Pereira, Eduardo L. M. Naves and Alcimar B. Soares

#### **Contributors**

Suélia De Siqueira Rodrigues Fleury Rosa, Adson Rocha, José Conceição Carvalho, Christakis Constantinides, Adriano Andrade, Juraj Kronek, Ema Paulovicova, Zuzana Kronekova, Lucia Paulovicova, Jozef Luston, Thanh-Dinh Thanh Nguyen, Venketesh N. Dubey, Neil Vaughan, Michael Wee, Richard Isaacs, Ajay Sonar, James Carroll, Vasilios Papaioannou, Ioannis Pneumatikos, Geovani Rodrigo Scolaro, Fernando Mendes De Azevedo, Christine Boos, Roger Walz, Elena Chernolovskaya, Natalya Petrova, Marina Zenkova, Tatiana Vasilieva, Erika G. Meraz, Homer Nazeran, Lidia Rascon Madrigal, Nelly Gordillo Castillo, Carlos Ramos, Liza Rodriguez, Galba Maria Campos-Takaki, Walid A. Zgallai

#### **© The Editor(s) and the Author(s) 2013**

The moral rights of the and the author(s) have been asserted.

All rights to the book as a whole are reserved by INTECH. The book as a whole (compilation) cannot be reproduced, distributed or used for commercial or non-commercial purposes without INTECH's written permission. Enquiries concerning the use of the book should be directed to INTECH rights and permissions department (permissions@intechopen.com).

Violations are liable to prosecution under the governing Copyright Law.

Individual chapters of this publication are distributed under the terms of the Creative Commons Attribution 3.0 Unported License which permits commercial use, distribution and reproduction of the individual chapters, provided the original author(s) and source publication are appropriately acknowledged. If so indicated, certain images may not be included under the Creative Commons license. In such cases users will need to obtain permission from the license holder to reproduce the material. More details and guidelines concerning content reuse and adaptation can be foundat http://www.intechopen.com/copyright-policy.html.

#### **Notice**

Statements and opinions expressed in the chapters are these of the individual contributors and not necessarily those of the editors or publisher. No responsibility is accepted for the accuracy of information contained in the published chapters. The publisher assumes no responsibility for any damage or injury to persons or property arising out of the use of any materials, instructions, methods or ideas contained in the book.

First published in Croatia, 2013 by INTECH d.o.o. eBook (PDF) Published by IN TECH d.o.o. Place and year of publication of eBook (PDF): Rijeka, 2019. IntechOpen is the global imprint of IN TECH d.o.o. Printed in Croatia

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Practical Applications in Biomedical Engineering Edited by Adriano O. Andrade, Adriano Alves Pereira, Eduardo L. M. Naves and Alcimar B. Soares p. cm. ISBN 978-953-51-0924-2

eBook (PDF) ISBN 978-953-51-6287-2


**1. Introduction**

[35] Pullammanappallil, S., Honjas, B., Louie, J., Siemens, J. A., and Miura, H., 2003, Comparative study of the refraction microtremors method: Using seismic noise and standard P-wave refraction equipment for deriving 1D shear-wave profiles, Proceed‐

ings of the 6th SEGJ International Symposium (January 2003, Tokyo), 192-197.

and Earthquake Engineering, 25, 871-887.

34 Engineering Seismology, Geotechnical and Structural Earthquake Engineering

inversion: Geophysics, v. 50, p. 2727-2741.

computer and structures Inc., Berkeley, California.

[39] Shapira, A., (1994).Seimological Bulletin of Israel. 1900 - 1994.

whittier, California.

[36] Raptakis D., Manakou M., Chavez-Garcia F., Makra K., Pitilakis K., (2005), 3D config‐ uration of Mygdonian basin and preliminary estimate of its site response,Soil Dynamics

[37] Riad, S., and H. Meyers, (1985).Earthquake catalog for the Middle East countries 1900

[38] Rogers, A. M., R. D. Borcherdt, P. A. Covington, and D. M. Perkins (1984). A compa‐ rative ground response study near Los Angeles using recordings of Nevada nuclear tests and the 1971 San Fernando earthquake, Bull. Seism. Soc. Am. 74, 1925-1949.

[40] Thorson, J. R., and Claerbout, J. F., 1985, Velocity-stack and slant-stack stochastic

[41] Uniform Building Code ( UBC,1985 ). International Conference of building officials

[42] Wilson, E.L, and Habiballah, A (1990)."SAP2000, Structural Analysis Programe"

[43] Woodword Clyde Consultant WWCC, (1985).Earthquake activity and dam stability for the Aswan High Dam, Egypt.High and Aswan Dames Ministry of Trregation, Cairo 2.

The general knowledge of seismicity of the Mexican Pacific Coast has been described in terms of its relationship within the regional context with the Middle America Trench, the convergence rate observed and predicted by plate tectonics processes, the use of seismic gap theory for forecast earthquakes on the region (Reyes [1]; Eissler and McNally [2]; Singh [3]; as well as Heaton and Kanamori [4]; among others) and prediction of strong ground motions using empirical relationship and seismic source scaling procedures (Somerville [5] and Somerville [6]).

The work here presented, mainly deals with the Colima-Jalisco region (ruptures areas of 1932, and 1973 earthquakes) as well as the remained gap of the Tecoman (2003) earthquake. The conduction of studies in this region to simulate seismic scenarios acquires special significance because of the hazard of an eventual large magnitude earthquake. For the large earthquakes recording in this region last and present century the rupture areas of the 1932, 1973 earthquakes and the small gap remainder from Tecoman earthquake the seismic convergence period have been exceeded or is in its limit.

Let us look into this with detail. Firstly, for the earthquakes of 3 and 18 June 1932, Nishenko and Singh [7] found that the average displacement on the fault of 1932 earthquakes as 155 cm. Pardo and Suarez [8] found that subduction rate of Rivera plate in this region is estimated to be from 2 to 5 cm/yr, take the small estimation of convergence rate of 2 cm/yr yields a recurrence period of about 77 years assuming that the convergence is entirely taken up by the seismic slip (Nishenko and Singh [7]). However considering a rate larger than 2 cm/yr the recurrence period could be much lower. The 79 years elapsed since 1932 indicate that the recurrence period has

© 2013 Gaytán et al.; licensee InTech. This is an open access article 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. © 2013 Gaytán et al.; licensee InTech. This is a chapter 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. © 2013 Gaytán et al.; licensee InTech. This is a paper 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.

expired. Although the rupture area of Manzanillo 1995 Mw 8.0 earthquake invades the rupture area of 1932 earthquakes, but represent less than 15 % of rupture area. Secondly, for the January 30 1973 earthquake (Mw 7.3) Reyes [1] estimate an average slip of 144 cm. For this region Minster [9] estimate a convergence rate of 5.6 cm/yr, this suggest a recurrence time period of about 25 years Reyes [1]. This recurrence period consider the various uncertainties and is in very good agreement with the interval between this earthquake and the preceding 1941 earthquake (32 years). The 38 years trascurred since 1973 indicate that the recurrence period have expired Reyes [1].

Thirdly, is the existence of a seismic gap in the region located between the rupture areas of the 1973 and the Tecoman earthquakes. In figure 1 Quintanar [12] shows that the aftershocks location of the Tecoman earthquake lies north of El Gordo graben and the aftershock area encompass part of the rupture area of the 1932 and 1995 earthquakes. The area between the limits of the rupture areas of the 1995 and the1973 earthquakes is what has been called the Colima seismic gap. The northwest area of this gap ruptured with the Tecoman earthquake in 2003. The other half of the gap, roughly to the southeast, remains quiet Quintanar [12].

The Use of Source Scaling Relationships in the Simulation of a Seismic Scenario in Mexico

http://dx.doi.org/10.5772/53274

37

The later show the existence of 3 different zones where is necessary to make a simulation of strong ground motions to estimate the response spectra. From these 3 zones the more impor‐ tant (by magnitude and area) is the region broken by earthquakes of 1932; however, the possibility of conduct a simulation in this area is limited by the poor instrumentation in the

In the case of small gap remainder from Tecoman and the rupture area of 1973 earthquakes, the Mw 5.3 earthquake of August 13, 2006 (element event) offered the opportunity to generate a seismic scenario for the studied area that constitutes a potential seismic source in this region in the near future. We apply: (i) the empirical Green's function method (EGFM) proposed by Irikura [13] to estimate the peak ground acceleration (PGA) and the acceleration time histories using the Somerville [6] relationship allowing us scaling from moderate to major earthquake. Traditionally the EGFM is well known technique commonly used to simulate an already occurred earthquake. The scientific community thinks that would be of great benefit if this technique can be applied to forecast an expected earthquake in Mexico. Under this premise, an immediate doubt arise because the absence of observed records (event we intent simulate) to compare with synthetics. Conduct a study to simulate strong ground motions under this situation makes difficult to constrain and validate the results, but at the same time is one of the more important challenge simulating a future earthquake. In order to overcome the absence of observed records two methodologies were applied: (i) The first one was Somerville [6] relationship together with the EGFM, and (ii) the second one was ground motions predictive equations (GMPE) relationships to make accurate estimation of strong motions. Aguirre and Irikura [14] used acceleration records of Mexican subduction earthquakes to validate the Somerville [5, 6] relationship for subduction earthquakes and found that the asperities size were well predicted by this relationship. The EGFM is a well established methodology used in the field of earth sciences to estimate the ground motions. What the EGFM requires to estimate the ground motions according to the tectonic conditions of the region, are the fault parameters determination. Works like the one done by Irikura [15] address the study of the factors involved with the inner and outer fault parameters of the source to do more accurate estimations of ground motions. Those outer and inner fault parameters are estimated from the inversion of the waveform in studies of rupture processes using strong ground records. Using the results of many kinematic inversions, Somerville [6] obtained some relationships that synthesize the main characteristics of the earthquakes, stated as follows: (i) the seismic moment, (ii) the rupture area, (iii) the slip average, (iv) the combined area of asperities, and (iv) the area of the largest asperity, among others. In this study we are using these relationships because of their great utility in the estimation of seismic ground motions. The above statement

past and therefore the absence of data the region.

**Figure 1.** Geographic regional map. (a) Contours show historic earthquakes in region (modified from Singh [10], local and regional stations where the 13 August 2006 earthquake (small star) were recorded: red triangles, big star epicen‐ tral location of simulated earthquake. (b) Local and regional stations within Colima state where earthquake was re‐ corded; blue triangles, IINGEN array and pentagons, RESCO array. (c) From Quintanar [11], map showing the best aftershock locations (empty circles). Large full square, shows the epicenter location of the Tecoman earthquake. Its fault plane solution is also shown. Large empty square shows the epicenter location of the Colima–Jalisco earthquake of 1995 (Mw = 8.0). Profiles AA' and BB' are cross sections onto which aftershocks were projected. Triangles show the locations of seismic stations.

Thirdly, is the existence of a seismic gap in the region located between the rupture areas of the 1973 and the Tecoman earthquakes. In figure 1 Quintanar [12] shows that the aftershocks location of the Tecoman earthquake lies north of El Gordo graben and the aftershock area encompass part of the rupture area of the 1932 and 1995 earthquakes. The area between the limits of the rupture areas of the 1995 and the1973 earthquakes is what has been called the Colima seismic gap. The northwest area of this gap ruptured with the Tecoman earthquake in 2003. The other half of the gap, roughly to the southeast, remains quiet Quintanar [12].

expired. Although the rupture area of Manzanillo 1995 Mw 8.0 earthquake invades the rupture area of 1932 earthquakes, but represent less than 15 % of rupture area. Secondly, for the January 30 1973 earthquake (Mw 7.3) Reyes [1] estimate an average slip of 144 cm. For this region Minster [9] estimate a convergence rate of 5.6 cm/yr, this suggest a recurrence time period of about 25 years Reyes [1]. This recurrence period consider the various uncertainties and is in very good agreement with the interval between this earthquake and the preceding 1941 earthquake (32 years). The 38 years trascurred since 1973 indicate that the recurrence period

36 Engineering Seismology, Geotechnical and Structural Earthquake Engineering

**Figure 1.** Geographic regional map. (a) Contours show historic earthquakes in region (modified from Singh [10], local and regional stations where the 13 August 2006 earthquake (small star) were recorded: red triangles, big star epicen‐ tral location of simulated earthquake. (b) Local and regional stations within Colima state where earthquake was re‐ corded; blue triangles, IINGEN array and pentagons, RESCO array. (c) From Quintanar [11], map showing the best aftershock locations (empty circles). Large full square, shows the epicenter location of the Tecoman earthquake. Its fault plane solution is also shown. Large empty square shows the epicenter location of the Colima–Jalisco earthquake of 1995 (Mw = 8.0). Profiles AA' and BB' are cross sections onto which aftershocks were projected. Triangles show the

have expired Reyes [1].

locations of seismic stations.

The later show the existence of 3 different zones where is necessary to make a simulation of strong ground motions to estimate the response spectra. From these 3 zones the more impor‐ tant (by magnitude and area) is the region broken by earthquakes of 1932; however, the possibility of conduct a simulation in this area is limited by the poor instrumentation in the past and therefore the absence of data the region.

In the case of small gap remainder from Tecoman and the rupture area of 1973 earthquakes, the Mw 5.3 earthquake of August 13, 2006 (element event) offered the opportunity to generate a seismic scenario for the studied area that constitutes a potential seismic source in this region in the near future. We apply: (i) the empirical Green's function method (EGFM) proposed by Irikura [13] to estimate the peak ground acceleration (PGA) and the acceleration time histories using the Somerville [6] relationship allowing us scaling from moderate to major earthquake. Traditionally the EGFM is well known technique commonly used to simulate an already occurred earthquake. The scientific community thinks that would be of great benefit if this technique can be applied to forecast an expected earthquake in Mexico. Under this premise, an immediate doubt arise because the absence of observed records (event we intent simulate) to compare with synthetics. Conduct a study to simulate strong ground motions under this situation makes difficult to constrain and validate the results, but at the same time is one of the more important challenge simulating a future earthquake. In order to overcome the absence of observed records two methodologies were applied: (i) The first one was Somerville [6] relationship together with the EGFM, and (ii) the second one was ground motions predictive equations (GMPE) relationships to make accurate estimation of strong motions. Aguirre and Irikura [14] used acceleration records of Mexican subduction earthquakes to validate the Somerville [5, 6] relationship for subduction earthquakes and found that the asperities size were well predicted by this relationship. The EGFM is a well established methodology used in the field of earth sciences to estimate the ground motions. What the EGFM requires to estimate the ground motions according to the tectonic conditions of the region, are the fault parameters determination. Works like the one done by Irikura [15] address the study of the factors involved with the inner and outer fault parameters of the source to do more accurate estimations of ground motions. Those outer and inner fault parameters are estimated from the inversion of the waveform in studies of rupture processes using strong ground records. Using the results of many kinematic inversions, Somerville [6] obtained some relationships that synthesize the main characteristics of the earthquakes, stated as follows: (i) the seismic moment, (ii) the rupture area, (iii) the slip average, (iv) the combined area of asperities, and (iv) the area of the largest asperity, among others. In this study we are using these relationships because of their great utility in the estimation of seismic ground motions. The above statement provides an efficient way to work when a limited number of parameters to be considered in numerical simulations is available.

previous temporal campaign in that area and from the support of other institutions with permanent instrumentation in that zone. Its epicenter, focal mechanism, and seismic moment were obtained from Centroid Moment Tensor Project [20]. The location of instruments that recorded this event (figure 1) is next described. The instruments were from permanent seismic networks: 15 Etna episensor wideband accelerographs from d.c. to 200 Hz at 200 samples per second from the national accelerations network of Instituto de Ingeniería (IINGEN) of Universidad Nacional Autonoma de Mexico (UNAM); two Guralp CMG40T-DM24 flat response wideband velocity type seismographs from 0.5 to 100 Hz at 100 samples per second from the network Red Sismica del Estado de Colima (RESCO). Secondly, data from temporal networks installed in the region as part of this project as follow: (i) four Altus Etna wideband accelerographs from d.c. to 100 Hz at 100 samples per second, four (ii) Geosig strong-motion recorder model 18 with analogue-digital converter, wideband accelerometers from d.c. to 100 Hz recording at 100 samples per second. Because 2 of the 25 records used in this study were velocity records, it was necessary to transform them to acceleration. Also, it was necessary to

The Use of Source Scaling Relationships in the Simulation of a Seismic Scenario in Mexico

http://dx.doi.org/10.5772/53274

39

The method used to model the target event requires a small magnitude event (earthquake of 13 August 2006) called element event, with hypocenter in close proximity to the earthquake that we want to simulate. For this particular case, the magnitude, location, focal mechanism and source parameters of the element event was reported by Harvard CMT (Mw 5.3, 18.45°N latitude and -103.63°W longitude, depth 23.5 km, strike 38°, dip 23°, and slip 96°, seismic moment 1.12e24 dyne-cm). For the simulated event (target event) and taking in consideration that the area in study is the region between the limits of the rupture areas of the Tecoman (2003) and the 1973 earthquakes, the hipocentral location was proposed just inside of the area in study and near to element event (18.45°N latitude and -103.75°W longitude). Considering the rupture area of 1973 earthquake and area of remainder gap of Tecoman earthquake we proposed 70 km along strike of fault area. Along the dip, we propose 80 km considering an intermediate value of dip length of neighbors earthquakes. Based on the above considerations

. Using equation (1), Somervile [6] we

M = 1/1.5 log M -10.73 w o ( ) ( ) (2)

remove the instrumental response of each of the different instruments.

the proposed effective rupture area is of 5600 km2

Where *A* is the rupture area and Mo is the seismic moment.

Using equation (2) by Kanamori [21], the maximum estimated MW magnitude is 7.3.

estimate a seismic moment of 1.1091e27 dine-cm.

**4. Method**

Finally from both estimations; it is said the PGAs, and the curves obtained with the two GMPE here used: (Ordaz [16], and Young's [17]), an trial and error iterative process of residuals minimization was conducted to identify the result that in the statistical sense better matched with the two GMPE here used.

The main contribution of this method is that it reflects a model that considers the source, the path, and the site effects. Another important contribution of the method is that reliable estimations about the energy distribution can be achieved in the high frequency band (between 0.1- and up to 10-Hz). This frequency range is of engineering interest because of the following reasons: (i) Many structures, including tall buildings and long bridges have their natural frequencies in the above frequency range, and (ii) 8 of the 10 major cities of this state are located in the sedimentary basins of the Colima graben and could amplify the ground motions in the frequency range of 0.1 to 10 Hz. It is therefore important to investigate how ground motions up to 10 Hz are generated from great subduction-zone earthquakes. This kind of investigations play a vital role in the effort to propose an scenario of strong ground motions from future large subduction earthquakes in the area in study and to evaluate the performance of structures subject to ground motions.


**1. Introduction**

Hugo Schiff, a German chemist, initially reported Schiff base in 1864 [1]. Schiff bases are organic molecules formed via condensation reaction of carbonyl compounds and primary amines [2]. The typical structure can be expressed as R'-CR = N-R", where R, R' and R" might vary. R and R' could be alkyl, aryl and heterocyclic structures with various substituents. The carbonyl group may be a constituent of an aldehyde or a ketone (>C=O)). Because Schiff bases contain an azomethine (>C=N-)) group, they are also known as azomethine or imine. The Schiff bases derived from aldehydes and ketones are known as aldimines and ketimines, respectively. A general

Schiff base condensation reaction involving the amine and the carbonyl functional group could be represented as follows (**Figure 1**).

When synthesizing Schiff bases, nucleophilic amines are used to attack electrophilic carbonyl compounds via a nucleophilic addition process, forming a hemiaminal group, and then the hemi-aminal group is dehydrated to generate imine compounds. In the first phase of the reaction, the amine reacts with the aldehyde or ketone to generate the unstable addition product carbinolamine. Carbinolamine undergoes acid- or base-catalyzed dehydration. Considering that carbinolamine is an alcohol, it undergoes a dehydration reaction when subjected to an acid catalyst (**Figure 2**). Reversible acid or base catalysis or heating often happens during the production of a Schiff base from aldehydes or ketones. When the product is isolated or water is evaporated, or both, the formation is pushed to completion. Hydrolysis of various Schiff bases by an aqueous acid or base yields the corresponding aldehydes, ketones, and amines.

Schiff bases with aryl substituents are significantly more stable and easier to synthesize, but those with alkyl substituents are relatively unstable [3, 4]. Aliphatic aldehyde Schiff bases are highly unstable and easily polymerizable, but aromatic aldehyde Schiff bases with efficient conjugation are more stable. Because aldehydes have less stearic hindrance than ketones, thus react faster. Extra carbon in ketones makes them less electrophilic than aldehydes. Schiff bases have received a great deal of attention due to their simplicity of synthesis, availability, and electronic characteristics. There is great interest in developing a wide range of applications in organic [5], inorganic [6, 7], coordination [8–10], bioinorganic [11, 12] and environmental chemistry [13–16]. Schiff base derivatives have been utilized in medical, pharmaceutical, metal refining, metallurgy, catalysis, food, sensing, filtration, environmental, photography and diagnostic applications.

The discovery of Schiff base was a major step forward for the discipline of coordination chemistry. When combined with a variety of transition metal ions, Schiff base ligands can generate stable metal complexes with a wide range of applications. The Schiff base has remarkable chelating characteristics. The presence of hydroxyl and thio-groups in azomethine groups may result in forming a penta or hexa ring structure with metal ions. Bidentate, tridentate, tetradentate, and polydentate Schiff bases are also possible. Because of the availability of a lone pair on the nitrogen atom, the Schiff base forms complexes with many metals. This lone pair aids in creating monodentate complexes, while adding other groups, such as OH and SH, may result in the formation of bidentate chelates. The azomethine nitrogen atom's lone pair of electrons and sp2 hybridized. As a result, it has substantial biological and chemical significance. Because there are more donor atoms in heterocyclic rings containing Schiff bases, they play a larger role in coordination chemistry [17–19].

Schiff bases show biological activities like nematicidal [20], insecticidal [21], antibacterial [22], antifungal [23], antileukaemia [24], anti-inflammatory [25], anti-HIV activity [26], antimycobacterial activity [27], antioxidant [28],

**Figure 1.** *General scheme of formation of Schiff bases.*

*Schiff Bases and Their Metal Complexes: Synthesis, Structural Characteristics and Applications DOI: http://dx.doi.org/10.5772/intechopen.108396*

**Figure 2.** *Mechanistic explanation of the formation of Schiff base.*

anticancer [29], and plant growth regulatory activity [30] among others. Besides biological applications, Schiff base and their metal complexes have enormous applications in analytical chemistry [31], dye industry [32], and corrosion inhibitors [33]. Schiff base has attracted the attention of many experimental and theoretical researchers due to their particular photo-luminescence [34] in the visible range and at room temperature and so applied in many realms such as microelectronics [35], optoelectronics [36] and biological sensors [37]. Schiff base shows excellent catalytic activity in various reactions such as polymerization reaction and reduction of thionyl chloride, reduction reaction of ketones, oxidation of organic compounds, aldol reaction, epoxidation of alkenes, hydrosilylation of ketones, Henry reaction, synthesis of bis (indolyl) methanes and Diels Alder reaction [38–40]. Synthetic chemists have used Schiff bases and related complexes for a wide variety of processes, including the oxidation of alkenes and the catalytic transformation of hydrocarbons into useful oxygenated derivatives such alcohols, aldehydes, and epoxides. A further area of intense curiosity is the catalysis of alkene oxidation by soluble transition metal complexes. Schiff bases have a wide range of donor sites, resulting in significant transition metal complexes. Schiff base metal complexes have been used in biological applications, resulting in important recent improvements in a variety of chemistry areas. Because of their unique treatment method, metal-containing antibacterial compounds appear to be promising candidates for brand-new antibiotic medications that restrict the growth of bacterial strains. The characteristics of Schiff base metal complexes vary depending on the ligands and the transition metal ion. Schiff bases have attracted a lot of interest because of their various chemical and physical properties, as well as their ease of production.


**1. Introduction**

Hydrogen is a clean energy carrier and favorable in relieving pollution, which gained much attention. Hydrogen production from biomass and organic wastes has great potential for sustainable development. Black liquor is the wastewater from the paper-making pulp industry and mainly contains inorganic pulping chemicals (NaOH and Na2CO3), organic components (lignin, hemicellulose, and their derivatives), and water [1]. It has the properties of high alkalinity, high chemical oxygen demand (COD) content, offensive odor, dark caramel color, and high moisture, so it will bring great threat to the environment and human health if not treated properly. Approximately 170 million tons of black liquor solids are generated annually [2]. Traditionally, black liquor is treated by combustion or conventional gasification [3, 4]. Both methods require an energy-intensive evaporation process, which leads to the waste of energy and production of secondary pollutants, such as NOx, SO2, and fine particles. Alternatively, the electrochemical treatment of black liquor is a clean method, but it requires high consumption of valuable electric power [5]. Therefore, more efficient and cleaner technology is desired as an alternative for handling black liquor.

Supercritical water gasification (SCWG) is a promising technology that can convert biomass and wastewater into hydrogen-rich gas. Relying on its unique physicochemical properties, SCW provides an excellent reaction environment for the gasification of biomass and organic wastes. Compared with traditional handling methods of black liquor, this technology has several advantages. For example, it reduces the energy dissipation of evaporation and allows wastewater with high moisture as feedstock, the alkali present in the black liquor can be served as a catalyst, no pollutants are generated, and the products are easy to separate and purify. Therefore, it has attracted the attention of many researchers and much progress has been made in this decade, and many studies have been published on this topic.

In this chapter, recent advances in SCWG of black liquor in recent decades will be reviewed. First, the effect of operating parameters, including temperature, concentration, and wall material, is discussed. In addition, the recovery of alkali salts in black liquor is introduced. Second, the catalysts used in this process and synergetic effect in its co-gasification with coal, biomass, and plastics are presented. Third, the poly-generation system of SCWG of black liquor is evaluated.

### **2. Gasification performance of black liquor**

#### **2.1 Influence of reaction temperature**

Temperature is a key parameter affecting the gas product composition and gasification efficiency in SCWG of black liquor. From the thermodynamic aspects, high temperatures tend to increase gasification efficiency and hydrogen production, while methane dominates the gas products at lower temperatures [6]. We performed thermodynamic analysis of SCWG of black liquor at different temperatures (300–800°C) with a pressure of 25 MPa and found that the temperature can greatly affect the gas composition [7]. CH4 and CO2 were the main components at low reaction temperatures, but their content decreased with increasing temperature. The fraction of H2 increased with temperature, which was above 50% at temperatures over 650°C, and the maximum equilibrium H2 fraction of 61.34% was obtained at 800°C. Gasification efficiency higher than 100% was attributed to the participation of water, which was also increased with temperature. The decrease in HHV (higher heating value) of the gas product with increasing temperature was because the fraction of H2 (HHV = 12.75 MJ/Nm3 ) increased, while the fraction of CH4 (HHV = 39.82 MJ/Nm3 ) decreased.

The experimental study also showed that temperature is a critical factor on the gas composition and yield. Boucard et al. [8] studied the gasification of 10 wt% black liquor at different temperatures (350–450°C, 25 MPa, and 60 min) and found the C content in the gas phase increased from less than 1% at 350°C to more than 25% at 450°C. The H2 yield increased from 2 mol/kg under subcritical conditions to 10–40 mol/kg under supercritical conditions. Previously, we studied SCWG of 9.5 wt% wheat straw black liquor at 400–600°C and 5 kg/h in a continuous flow system [9]. When the temperature was increased from 400°C to 600°C, the gas yield *Recent Advances in Supercritical Water Gasification of Pulping Black Liquor for Hydrogen... DOI: http://dx.doi.org/10.5772/intechopen.105566*

nearly doubled, and gasification efficiency and H2 yield increased from 28.05% and 6.82 mol/kg to 67.89% and 11.26 mol/kg, respectively. The COD concentration and pH decreased from 95,000 mg/L and 11.3 in the raw black liquor to 2160 mg/L and 7.0–7.8 at 600°C, respectively. In addition, the color also changed from dark caramel to clear as pure water (**Figure 1**). SCWG of black liquor at higher temperatures (600–750°C) was investigated in a batch reactor [7]. The H2 fraction increased from 55% to nearly 70% as the temperature increased from 600°C to 750°C. And the maximum carbon gasification efficiency of 94.10% was obtained at 750°C and 30 min.

#### **2.2 Influence of black liquor concentration**

The concentration of weak black liquor produced from pulping varied in the range of 10–20 wt% [10], which can influence the gasification performance. **Figure 2** showed the influence of black liquor concentration on the equilibrium composition, yield, and HHV of the gas product. The effect of concentration on gas composition was almost opposite to temperature. Increasing the concentration greatly decreased the H2 fraction but increased the fraction of carbonaceous gas (CO2, CH4, and CO), so increasing the concentration increased the heating value of the gas product.

In the experiments with both continuous systems and batch reactors, high H2 yields and fractions were obtained from gasification of diluted black liquor. The gas yield

#### **Figure 1.**

*The color changes of black liquor after SCWG in a tubular reactor at different temperatures (concentration = 9.5 wt%; pressure = 25 MPa) [9].*

#### **Figure 2.**

*Equilibrium gas composition (A) and GE and HHV of the gas product (B) of wheat straw black liquor with change of concentration (pressure = 25 MPa; concentration = 9.5 wt %) [7].*

almost doubled when the concentration decreased from 9.5 wt% to 3 wt% at 550°C [7, 11]. Casademont et al. also found that the gas yield and H2 yield increased more than fourfold as the black liquor concentration decreased from 2.43 wt% to 0.81 wt% in SCWG at 600°C [12]. At higher concentrations, reducing the concentration from 20 wt% to 10 wt% increased hydrogen in black liquor converted to H2 from 7.5 to 9.8% at 650°C [1]. Moreover, the H2 yield obtained by gasification of low-concentration black liquor (below 3 wt%) can reach over 24 mol/kg, while the gas products from gasification of above 10 wt% black liquor were mainly composed of C1–C4 hydrocarbons [1, 9, 12]. Therefore, high concentration black liquor is more difficult to gasify. However, a lower concentration of black liquor will improve the system scale and energy loss, so a proper concentration needs to be selected through further detailed investigation.

#### **2.3 Influence of reactor wall material**

In SCWG, water will fill the entire space of the reactor and Ni was an effective catalyst in SCWG [13], so the material of the reactor wall can also affect the gasification performance. Casademont et al. [12] obtained different gasification efficiencies of black liquor in SCWG from the literatures [7, 9], and they attributed the difference mainly to the different reactor materials. They proposed that the reactor made of Inconel 625 was more favorable to gasification than other material. De Blasio et al. [14] investigated SCWG of black liquor in stainless steel 316 and Inconel 625 reactors. It was found that the carbon gasification efficiency obtained was similar in these two reactors, while the hydrogen gasification efficiency obtained in Inconel 625 was much higher than that of the stainless steel 316 reactor at both 600 and 700°C. Hydrogen production with the Inconel 625 reactor was also much higher than that with stainless steel 316 reactor at 600°C. Inconel 625 was slightly better than stainless steel 316 in hydrogen production at 500°C and close to each other at 700°C. Besides, the hot gas efficiency obtained with Inconel 625 reactor was higher than that with stainless steel 316 at 600–700°C, and the maximum value exceeded 80% at 700°C. In a word, the treatment of black liquor in the Inconel 625 reactor can increase hydrogen production and inhibit the formation of tar and char. Özdenkçi et al. [15] investigated the technoeconomic feasibility of SCWG of black liquor in Inconel 625 and stainless steel 316 reactors. It showed that Inconel 625 outperformed stainless steel 316 in terms of energy production, hydrogen production, resistance to pulping chemical losses, and changes in energy prices.

#### **2.4 Influence of alkali in black liquor**

The role of alkali contained in black liquor in the gasification process was investigated by comparing the effect of black liquor and lignin as additives on SCWG of coal [16]. It was found that the fraction of CO decreased significantly, while the content of H2 and CO2 increased when the additive was changed from lignin to black liquor. It was probably because the alkali in black liquor promoted the water-gas shift reaction. The total gas yield of coal with black liquor (12.07 mol/kg) was higher than that of coal with lignin (6.90 mol/kg). Hawangchu et al. [17] investigated the effect of inherited alkali on product distribution by comparing the gasification performance of soda black liquor, kraft black liquor, and lignin compound in SCW. Hydrogen from soda black liquor was always higher than that of lignin, confirming the promotion of alkali on the water-gas shift reaction. They proposed that both the dissolution of organic substances and inhibition of coke production by alkalis promoted gas production.

*Recent Advances in Supercritical Water Gasification of Pulping Black Liquor for Hydrogen... DOI: http://dx.doi.org/10.5772/intechopen.105566*

In addition, Rönnlund et al. [18] studied the effect of the addition of alkalis (KOH, K2CO3, NaOH) and black liquor on SCWG of paper sludge. Similarly, the addition of black liquor improved the hydrogen production and gasification efficiency of paper sludge gasification. Furthermore, the promotion extent of black liquor on gasification was similar to that of alkali salts.

### **3. Recovery of alkali in SCWG of black liquor**

Alkali salts are another main component of black liquor, including cooking chemicals (NaOH and Na2S), as well as derived salts such as Na2CO3, Na2SO4, and Na2SO4 [19]. The organic components in black liquor can be converted in SCWG into gas products, while the inorganic salts still reside in the reactor. Thus, the salts can be recovered and reused in the pulping process as cooking chemicals to reduce the pulp cost. In conventional treatment, the recovery of alkali can be realized by burning the organic components in black liquor [20]. Depending on the unique physicochemical properties of SCW, the alkali can also be recovered during SCWG. The literature showed that the dielectric constant of water decreases sharply with increasing temperature around the critical point [21], which reduces the solubility of inorganic substances and enables the recovery of alkali salts.

Alkali was the main cooking chemical (NaOH), so the recovery of Na+ salts in SCWG of black liquor was investigated [22, 23]. We studied the distribution of alkali during SCWG in a fluidized-bed reactor using glucose as the model compound and attempted to recover the alkali salts [22]. For the extremely low solubility, the Na+ salts were mainly precipitated in SCW and distributed in the reactor during gasification, which were not carried out of the reactor by the fluid in the form of ions [22]. While the fluid temperature in the reactor was reduced close to the critical point after the gasification, the alkali was dissolved in the water and flowed out as the reaction effluent. As a result, the Na+ content and pH value of the effluent changed dramatically with the temperature in the cooling process of the reactor (**Figure 3**). The Na+ content of the effluent was 10–30 mg/L when the temperature was higher than 360°C, and it increased sharply when the temperature dropped to 355°C and reached a maximum value of 1815 mg/L at 335°C. With flushing of the reactor for a certain time, the Na+ content dropped to 86 mg/L. Cooling fluid in the range of 360–200°C achieved

**Figure 3.** *The Na+ content of effluent varies with the temperature of the fluid [22].*

a Na+ recovery of 81.07%, and the losses may be attributed to salt entrainment. Based on this result, we proposed an alkali recovery method during SCWG of black liquor, in which the alkalis can be recovered by cooling the reactor after operating for a certain time. And for the fluidized-bed reactor, the velocity of the fluid was important to constrain the alkali solids in the reactor and reduce the alkali salt entrainment and losses. Besides NaOH, the inorganic components of the effluent also contained Na2CO3 and NaHCO3 generated by the reaction of NaOH with CO2. Regeneration from Na2CO3/NaHCO3 to NaOH can be achieved by a conventional method (causticization reaction) with CaO [22]. Some methods can be used to improve the recovery of NaOH in SCWG of black liquor. Fedyaeva et al. [23] studied SCWG of Na2CO3-free black liquor and calculated the mole ratio of 2NaOH/Na2CO3. The ratio could reach 4 mol% without water flow. The amount of produced Na2CO3 can be controlled by pumping SCW through the reactor to carry out CO2 and reduce the residence time of SCW. The ratio can reach 14–18% at 710–750°C and 30 MPa. It is a simple and effective method to achieve highly economic recovery of alkali salts without the addition of chemicals.