Author details

Luís Adriano Santos do Nascimento\*, Deborah Terra de Oliveira, Alex Nazaré de Oliveira, Luiza Helena de Oliveira Pires, Carlos Emmerson Ferreira da Costa and Geraldo Narciso da Rocha Filho

\*Address all correspondence to<EMAIL_ADDRESS>
Federal University of Pará, Belém, Brazil

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Valorization of Wastes for Biodiesel Production: The Brazilian Case

http://dx.doi.org/10.5772/intechopen.81879

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**Chapter 3**

**Provisional chapter**

**Properties of Torrefied Palm Kernel Shell via**

**Properties of Torrefied Palm Kernel Shell via**

DOI: 10.5772/intechopen.81374

This study describes the characteristic and thermal properties of torrefied palm kernel shell (PKS) by microwave irradiation pretreatment. The microwave power level (200, 300, 450, and 600 W) and processing time (4, 8, and 12 min) were used in this study. The pretreated samples were analyzed for mass and energy yield, calorific value, proximate and elemental composition, and thermal decomposition. Results showed that the characteristic of pretreated PKS was enhanced by increasing the microwave power level and processing the time. The oxygen content and O/C ratio of torrefied PKS were reduced by increasing the microwave power level. The carbon content of pretreated PKS, which was closed to the untreated MB coal properties with comparable calorific value, was obtained. The microwave power level of 450 W and processing time of 8 min were suitable to upgrade the PKS to a respectable quality feedstock. Thus, it can be concluded that the alteration in physical, chemical, and thermal properties of torrefied PKS discovered the potential of this feedstock to be applied in subsequent thermochemical conversion

**Keywords:** pretreatment, torrefaction, microwave irradiation, palm kernel shell,

, SOx

lization of the world energy [1]. In the midst of limited availability of fossil fuels and high level of air pollution, energy efficient technologies are gaining importance, and gasification, being

> © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,

distribution, and reproduction in any medium, provided the original work is properly cited.

, and NOx

has become a concern on the uti-

**Microwave Irradiation**

**Microwave Irradiation**

Razi Ahmad, Mohd Azlan Mohd Ishak, Nur Nasulhah Kasim and Khudzir Ismail

Razi Ahmad, Mohd Azlan Mohd Ishak, Nur Nasulhah Kasim and Khudzir Ismail

http://dx.doi.org/10.5772/intechopen.81374

such as pyrolysis and gasification.

In recent years, the increasing emission of CO2

**Abstract**

gasification

**1. Introduction**

Additional information is available at the end of the chapter

Additional information is available at the end of the chapter

#### **Properties of Torrefied Palm Kernel Shell via Microwave Irradiation Properties of Torrefied Palm Kernel Shell via Microwave Irradiation**

DOI: 10.5772/intechopen.81374

Razi Ahmad, Mohd Azlan Mohd Ishak, Nur Nasulhah Kasim and Khudzir Ismail Razi Ahmad, Mohd Azlan Mohd Ishak, Nur Nasulhah Kasim and Khudzir Ismail

Additional information is available at the end of the chapter Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.81374

#### **Abstract**

[54] Martins GI, Secco D, Tokura LK, Bariccatti RA, Dolci BD, Santos RF. Potential of tilapia oil and waste in biodiesel production. Renewable and Sustainable Energy Reviews. 2015;42:

[55] Rodrigues JS, Valle CP, Guerra PAGP, Rios MAS, Malveira JQ, Ricardo NMPS. Study of kinetics and thermodynamic parameters of the degradation process of biodiesel produced from fish viscera oil. Fuel Processing Technology. 2017;161:95-100. DOI: 10.1016/j.fuproc.

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[57] Reis MC, Freitas FA, Lachter ER, Gil RASS, Nascimento RSV, Poubel RL, et al. Biodiesel production from fatty acids of refined vegetable oils by heterogeneous acid catalysis and microwave irradiation. Quimica Nova. 2015;10:1307-1312. DOI: 10.5935/0100-4042.20150163

[58] Aguiar VM, Souza LA, Galdino FS, Silva MMC, Teixeira VG, Lachter ER. Sulfonated poly (divinylbenzene) and poly (styrene-divinylbenzene) as catalysts for esteri fi cation of fatty

[59] Aranda DAG, Antunes OAC. Catalytic Process to the Esterification of Fatty Acids Present in the Acid Grounds of the Palm Using Acid Solid Catalysts; 2004. WO Patent<PHONE_NUMBER>

[60] Pires LHO, de Oliveira AN, Monteiro OV Jr, Angélica RS, Costa CEF, Zamian JR, et al. Esterification of a waste produced from the palm oil industry over 12-tungstophosforic acid supported on kaolin waste and mesoporous materials. Applied Catalysis B: Environ-

[61] Oliveira JFG, Lucena IL, Saboya RMA, Rodrigues ML, Torres AEB, Fernandes FAN, et al. Biodiesel production from waste coconut oil by esterification with ethanol: The effect of water removal by adsorption. Renewable Energy. 2010;35:2581-2584. DOI: 10.1016/j.renene.

[62] Souza AF, Rodriguez DM, Ribeaux DR, Luna MAC, Lima e Silva TA, Silva Andrade RF, et al. Waste soybean oil and corn steep liquor as economic substrates for bioemulsifier and biodiesel production by Candida lipolytica UCP 0998. International Journal of Molecular

[63] Jesus SS, Santana A, Ponce GHSF, Maciel FR. Potential use of vegetable waste for biofuel production. Journal of Chemical Technology and Biotechnology. 2017;92:90-99. DOI:

[64] Gomes MG, Pasquini D. Utilization of eggshell waste as an adsorbent for the dry purification of biodiesel. Environmental Progress & Sustainable Energy. 2018:1-7. DOI: 10.1002/

mental. 2014;160–161:122-128. DOI: 10.1016/j.apcatb.2014.04.039

Sciences. 2016;17:1-18. DOI: 10.3390/ijms17101608

234-239. DOI: 10.1016/j.rser.2014.10.020

Journal. 2013;81:15-23. DOI: 10.1016/j.bej.2013.09.017

acids. Renewable Energy. 2017;114:725-732

2017.03.013

28 Biofuels - Challenges and opportunities

2010.03.035

10.1002/jctb.5002

ep.12870

This study describes the characteristic and thermal properties of torrefied palm kernel shell (PKS) by microwave irradiation pretreatment. The microwave power level (200, 300, 450, and 600 W) and processing time (4, 8, and 12 min) were used in this study. The pretreated samples were analyzed for mass and energy yield, calorific value, proximate and elemental composition, and thermal decomposition. Results showed that the characteristic of pretreated PKS was enhanced by increasing the microwave power level and processing the time. The oxygen content and O/C ratio of torrefied PKS were reduced by increasing the microwave power level. The carbon content of pretreated PKS, which was closed to the untreated MB coal properties with comparable calorific value, was obtained. The microwave power level of 450 W and processing time of 8 min were suitable to upgrade the PKS to a respectable quality feedstock. Thus, it can be concluded that the alteration in physical, chemical, and thermal properties of torrefied PKS discovered the potential of this feedstock to be applied in subsequent thermochemical conversion such as pyrolysis and gasification.

**Keywords:** pretreatment, torrefaction, microwave irradiation, palm kernel shell, gasification

#### **1. Introduction**

In recent years, the increasing emission of CO2 , SOx , and NOx has become a concern on the utilization of the world energy [1]. In the midst of limited availability of fossil fuels and high level of air pollution, energy efficient technologies are gaining importance, and gasification, being

> © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

a highly efficient technology, has received significant attention [2]. Currently, coal is the main feedstock in gasification and is expected to be applied as the energy resource for many decades ahead. However, this direction is difficult to achieve due to the increase in energy demand that had caused the shortage supply and reduction of coal [3]. Consequently, one of the approaches is to utilize the biomass in thermochemical conversion such as pyrolysis, liquefaction, and gasification. The traditional use of biomass has been restricted to cooking and heating purposes, which has affected adverse impacts such as land degradation and desertification. However, the current use of biomass with a high-quality energy carrier transformed from raw biomass for electricity and heat production can substantially reduce emissions from the conventional power plants. This ability to convert raw biomass into convenient energy carriers increases the interest on biomass use for energy purpose, especially the lignocellulosic biomass [4].

conversion such as in gasification. As a result, prior to gasification, it might be attractive to

Properties of Torrefied Palm Kernel Shell via Microwave Irradiation

http://dx.doi.org/10.5772/intechopen.81374

31

A pretreatment method prior to thermal conversion is required in direction to reduce some of the aforementioned problems. Thus, torrefaction pretreatment appears to be an effective route. The thermal pretreatment or torrefaction at low temperature between 200 and 300°C, which operated in the nonappearance of oxygen, upgraded the untreated feedstock to more value feedstock. Nitrogen is generally used as carrier gas to provide a nonoxidizing atmosphere in most laboratory tests. Since torrefaction is conducted at conditions similar to those of pyrolysis that usually takes place between 350 and 650°C, torrefaction has also been known as mild pyrolysis [16]. The pretreated biomass has high calorific value and carbon fraction with low moisture content and O/C ratio compared to the untreated or original material. The energy value of pre-

treated material will increase with increasing carbon fraction and calorific value [17].

moisture removal and hemicellulose breakdown, which produce H2

The previous studies have also shown other advantages of this torrefaction pretreatment, such as it improves feedstock hydrophobicity, homogeneity, and grindability [4, 18]. Satpathy et al. [19] found that the torrefied wheat and barley straw are more hydrophobic and the moisture uptake is reduced by 61–68% under suitable torrefaction condition. Torrefaction of marula seeds and blue gum improves the higher heating value and energy content of the biomass. The weight loss also increases when the torrefaction temperature increases due to

Torrefaction temperature is one of the important parameters in torrefaction pretreatment [4]. Ibrahim et al. [21] found that the lower temperature and shorter residence time were the best treatment to achieve good physical properties with a relatively high energy yield. When treated at these conditions, the softwood mixture had the highest energy (95%), followed by the hardwood mixture (80%), then willow (79%), and finally eucalyptus (75%). Increasing the severity of the torrefaction conditions greatly improved the physical characteristics of the torrefied biomass, in terms of grindability properties and hydrophobicity. The optimum temperatures were reliant on raw material, and consequently, the effects specify that careful optimization is necessary for all feedstock types to increase the advantages of torrefaction at the same time preserving an adequate energy yield. As pretreatment conditions became more severe between temperature of 250 and 300°C, this led to a more qualified and energydense solid fuel with higher fixed carbon content, increased calorific values, and reduced hydrogen and oxygen contents [22]. By increasing the torrefaction temperature, the weight loss increased and bulk density decreased. The torrefied wood samples improved solid fuel property with high fuel ratio, which are close to lignite coal [23]. Mamvura et al. [20] found that the nonoxidative conditions with low heating rates and shorter residence time resulted in the best torrefied biomass. The increase in HHV together with increase in energy density for torrefied marula seeds during investigation intended that it is potential to coconversion with coal making it a promising biomass source. Therefore, the pretreated or torrefied biomass, which has been improved in energy density, hydrophobicity, and grindability, overcomes the weakness of untreated biomass and is then driven to be applied in

O, CO, CO2

, and other

transform the biomass characteristics.

hydrocarbons [20].

thermochemical conversion [4, 16].

Biomass is one of the capable renewable energy sources and is applied as solid, liquid, and gas fuels [5]. The biomass is an appealing concern worldwide, because of its nonedible characteristic, carbon neutrality, and relative abundance. Moreover, the rising worries about the effects of CO2 emissions from fossil fuels call for sustainable energy sources, such as biomass [6]. In Malaysia, oil palm residues are considered to be the most plentiful biomass and the greatest prospects for fuel generation. Malaysia produces about 47% of the world's palm oil source and can be reflected as one of the world's largest producers of palm oil. Therefore, Malaysia creates huge quantity of oil palm biomass including palm kernel shell (PKS), oil palm trunks, oil palm fronds, empty fruit bunches, and fibers as residues from harvesting and processing activities [7]. The PKS as one of the residues from oil palm industry generated about 4.19 MnT in 2016 [8]. Therefore, PKSs appear to have prominent capacities to become an alternative source of energy for the country.

However, the utilization of biomass, which is a renewable and environmental friendly resource during thermal conversion, imposed several problems. The untreated biomass has the drawbacks as follows:

Likewise, it is reasonably challenging for straight application of untreated PKS as raw material for fuel production such as gasification or pyrolysis. Typically, the palm plantations and their processing plants are located in rural areas. Thus, the untreated PKS is opened to fungal attack and biodegradation through storage and transportation. The high moisture content also can interrupt the thermal conversion process for energy production [9]. The low energy density of PKS, normally 18 MJ/kg, with high moisture content typically around 10 wt.% as a result of its hygroscopic character, is a weakness of biomass [10–12]. As shown by the previous researcher [13–15], highly oxygenated biomass with high O/C ratio will lower the gasification efficiency in contrast with low O/C feedstock such as coal. Consequently, these properties of the untreated PKS were associated with several problems in biomass thermal conversion such as in gasification. As a result, prior to gasification, it might be attractive to transform the biomass characteristics.

a highly efficient technology, has received significant attention [2]. Currently, coal is the main feedstock in gasification and is expected to be applied as the energy resource for many decades ahead. However, this direction is difficult to achieve due to the increase in energy demand that had caused the shortage supply and reduction of coal [3]. Consequently, one of the approaches is to utilize the biomass in thermochemical conversion such as pyrolysis, liquefaction, and gasification. The traditional use of biomass has been restricted to cooking and heating purposes, which has affected adverse impacts such as land degradation and desertification. However, the current use of biomass with a high-quality energy carrier transformed from raw biomass for electricity and heat production can substantially reduce emissions from the conventional power plants. This ability to convert raw biomass into convenient energy carriers increases the

interest on biomass use for energy purpose, especially the lignocellulosic biomass [4].

effects of CO2

30 Biofuels - Challenges and opportunities

an alternative source of energy for the country.

**ii.** High moisture and oxygenated compound

the drawbacks as follows: **i.** Low energy content

**iii.** Hygroscopic behavior

**iv.** Poor grindability

Biomass is one of the capable renewable energy sources and is applied as solid, liquid, and gas fuels [5]. The biomass is an appealing concern worldwide, because of its nonedible characteristic, carbon neutrality, and relative abundance. Moreover, the rising worries about the

[6]. In Malaysia, oil palm residues are considered to be the most plentiful biomass and the greatest prospects for fuel generation. Malaysia produces about 47% of the world's palm oil source and can be reflected as one of the world's largest producers of palm oil. Therefore, Malaysia creates huge quantity of oil palm biomass including palm kernel shell (PKS), oil palm trunks, oil palm fronds, empty fruit bunches, and fibers as residues from harvesting and processing activities [7]. The PKS as one of the residues from oil palm industry generated about 4.19 MnT in 2016 [8]. Therefore, PKSs appear to have prominent capacities to become

However, the utilization of biomass, which is a renewable and environmental friendly resource during thermal conversion, imposed several problems. The untreated biomass has

Likewise, it is reasonably challenging for straight application of untreated PKS as raw material for fuel production such as gasification or pyrolysis. Typically, the palm plantations and their processing plants are located in rural areas. Thus, the untreated PKS is opened to fungal attack and biodegradation through storage and transportation. The high moisture content also can interrupt the thermal conversion process for energy production [9]. The low energy density of PKS, normally 18 MJ/kg, with high moisture content typically around 10 wt.% as a result of its hygroscopic character, is a weakness of biomass [10–12]. As shown by the previous researcher [13–15], highly oxygenated biomass with high O/C ratio will lower the gasification efficiency in contrast with low O/C feedstock such as coal. Consequently, these properties of the untreated PKS were associated with several problems in biomass thermal

emissions from fossil fuels call for sustainable energy sources, such as biomass

A pretreatment method prior to thermal conversion is required in direction to reduce some of the aforementioned problems. Thus, torrefaction pretreatment appears to be an effective route. The thermal pretreatment or torrefaction at low temperature between 200 and 300°C, which operated in the nonappearance of oxygen, upgraded the untreated feedstock to more value feedstock. Nitrogen is generally used as carrier gas to provide a nonoxidizing atmosphere in most laboratory tests. Since torrefaction is conducted at conditions similar to those of pyrolysis that usually takes place between 350 and 650°C, torrefaction has also been known as mild pyrolysis [16]. The pretreated biomass has high calorific value and carbon fraction with low moisture content and O/C ratio compared to the untreated or original material. The energy value of pretreated material will increase with increasing carbon fraction and calorific value [17].

The previous studies have also shown other advantages of this torrefaction pretreatment, such as it improves feedstock hydrophobicity, homogeneity, and grindability [4, 18]. Satpathy et al. [19] found that the torrefied wheat and barley straw are more hydrophobic and the moisture uptake is reduced by 61–68% under suitable torrefaction condition. Torrefaction of marula seeds and blue gum improves the higher heating value and energy content of the biomass. The weight loss also increases when the torrefaction temperature increases due to moisture removal and hemicellulose breakdown, which produce H2 O, CO, CO2 , and other hydrocarbons [20].

Torrefaction temperature is one of the important parameters in torrefaction pretreatment [4]. Ibrahim et al. [21] found that the lower temperature and shorter residence time were the best treatment to achieve good physical properties with a relatively high energy yield. When treated at these conditions, the softwood mixture had the highest energy (95%), followed by the hardwood mixture (80%), then willow (79%), and finally eucalyptus (75%). Increasing the severity of the torrefaction conditions greatly improved the physical characteristics of the torrefied biomass, in terms of grindability properties and hydrophobicity. The optimum temperatures were reliant on raw material, and consequently, the effects specify that careful optimization is necessary for all feedstock types to increase the advantages of torrefaction at the same time preserving an adequate energy yield. As pretreatment conditions became more severe between temperature of 250 and 300°C, this led to a more qualified and energydense solid fuel with higher fixed carbon content, increased calorific values, and reduced hydrogen and oxygen contents [22]. By increasing the torrefaction temperature, the weight loss increased and bulk density decreased. The torrefied wood samples improved solid fuel property with high fuel ratio, which are close to lignite coal [23]. Mamvura et al. [20] found that the nonoxidative conditions with low heating rates and shorter residence time resulted in the best torrefied biomass. The increase in HHV together with increase in energy density for torrefied marula seeds during investigation intended that it is potential to coconversion with coal making it a promising biomass source. Therefore, the pretreated or torrefied biomass, which has been improved in energy density, hydrophobicity, and grindability, overcomes the weakness of untreated biomass and is then driven to be applied in thermochemical conversion [4, 16].

Most of the biomass torrefactions applied the conventional electric heater, while there is an alternative technology designated microwave irradiation. Microwave technology has expanded remarkable importance in the thermochemical pretreatment of waste materials, including biomass, waste cooking oil, scrap tires, and others. Innovative fields are being exposed in which microwave can be applied as an alternative source of heating. The application of microwave in waste treatment originated about two decades ago. Therefore, it can be considered at an early stage of enlargement [24]. Microwave irradiation is an electromagnetic irradiation in the range of wavelengths from 0.01 to 1 m and the equivalent frequency range of 0.3–300 GHz. Normally, the microwave reactors for chemical synthesis and all domestic microwave ovens operate at 2.45 GHz frequency, which corresponds to a wavelength of 12.25 cm. Microwave irradiation has attracted much attention in recent years due to the advantages associated with dielectric heating effects. Microwave dielectrics are known as a material, which absorbs microwave irradiation; thus, microwave heating is called dielectric heating [25]. The pretreatment using microwave irradiation is an effective method for upgrading the biomass [26]. Unlike conventional heating technique in which heat gradually enters into samples over normal heat transfer mechanisms (convection, conduction, and radiation) [27], microwave irradiation employs electromagnetic energy to produce heat, which can enter deep into samples, permitting heating to initiate volumetrically [28]. Microwave irradiation has many advantages such as:

Consequently, more research is required to entirely understand the characteristic of torrefied biomass using microwave irradiation prior to further thermochemical conversion. It is also necessary to understand the thermal decomposition of torrefied biomass during pyrolysis in thermogravimetric analyzer (TGA) since, in the thermal conversion studies, the beginning stage involves the feedstock devolatilization. Therefore, in this study, the PKS was initially torrefied in microwave, and the properties of torrefied PKS were explored. Subsequently, the thermal decomposition and behavior of torrefied PKS during pyrolysis process using TGA

Properties of Torrefied Palm Kernel Shell via Microwave Irradiation

http://dx.doi.org/10.5772/intechopen.81374

33

PKS as a biomass sample was obtained from United Oil Palm Mill Sdn. Bhd., Nibong Tebal, Penang, Malaysia. The PKS is produced from the shell/kernel separator. The PKS sample was crushed and sieved through progressively finer screen to obtain particle sizes in the range of 200–400 μm. The untreated PKS sample was dried in an oven at 105°C for 24 h for rendering moisture-free and finally stored in an air-tight container until the experiments and analyses were carried out. The pre-drying is needed to avoid further biodegradation of the sample through storage since the moisture mass fraction of the raw PKS is relatively high [33]. Moreover, the pre-drying is used to simulate the industrial practice of sun-drying the

The torrefaction experiment was carried out in a domestic microwave oven (Samsung) with technical specifications of ~240 V and 50 Hz and a maximum power of 800 W. The microwave output power levels of 200, 300, 450, and 600 W were used in this study. The untreated PKS of 5 g was put in the sample crucible placed at the center of the microwave oven. Then, the nitrogen gas at a flow rate of 50 mL/min was purged in the reaction compartment to retain the inert atmosphere condition. After 10 min purging, the microwave system was turned on, and the microwave output power level was selected with respective processing time of 4, 8, and 12 min. The inert atmosphere condition was continued during the microwave irradiation. The power supply was turned off, and the nitrogen gas flow was stopped after the set processing time was achieved. The final temperature of the pretreated PKS was measured using infrared thermometer immediately after the pretreatment process. The final weight of pretreated PKS was measured once it reached the room temperature. The experiment under all of the studied parameters was repeated to confirm the measurement quality and repeatability of the achieved results.

), mass yield (*Ym*), and energy yield (*Ye*

) of the pretreated samples

**2.3. Calculation of solid conversion, mass yield, and energy yield**

were calculated according to Eqs. (1)–(3), respectively:

were examined.

**2. Method**

**2.1. Materials**

materials before storage [6].

**2.2. Torrefaction experiment**

The solid conversion (*Xs*

Wang et al. [30] utilized microwave irradiation to upgrade the properties of rice husk and sugarcane residues by varying different parameters, including microwave power level and processing time. They found that the suitable microwave power levels are proposed to be set between 250 and 300 W for the torrefaction of these two agricultural wastes. Also, with appropriate processing time, the caloric value is able to increase 26% for rice husk and 57% for sugarcane residue. Huang et al. [31] found that higher microwave power levels contributed to higher heating rate and reaction temperature and therefore produced the torrefied biomass with higher heating value and lower H/C and O/C ratios. The torrefied biomass or biochar probably substitutes coal due to high heating value and fuel ratio as well as low atomic H/C and O/C ratios. The microwave torrefaction of *Leucaena* produced thermally stable biochar compared with sewage sludge at lower microwave power levels, which means that the microwave heating performance of *Leucaena* is better. Compared with conventional torrefaction, mass and energy yields of microwave torrefaction were lower, which might be attributable to the further severe reaction accomplished by microwave irradiation [32].

Consequently, more research is required to entirely understand the characteristic of torrefied biomass using microwave irradiation prior to further thermochemical conversion. It is also necessary to understand the thermal decomposition of torrefied biomass during pyrolysis in thermogravimetric analyzer (TGA) since, in the thermal conversion studies, the beginning stage involves the feedstock devolatilization. Therefore, in this study, the PKS was initially torrefied in microwave, and the properties of torrefied PKS were explored. Subsequently, the thermal decomposition and behavior of torrefied PKS during pyrolysis process using TGA were examined.


**RHEOLOGY - NEW CONCEPTS, APPLICATIONS AND METHODS**

Edited by **Rajkumar Durairaj**

#### **Rheology - New Concepts, Applications and Methods**

http://dx.doi.org/10.5772/47871 Edited by Rajkumar Durairaj

#### **Contributors**

Rajkumar Durairaj, Abu-El Hassan, Martin Williams, Talero, Trofimov, Jeshwanth K. Rameshwaram

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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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**4. Choline-based probes**

In recent years, choline metabolism has received a growing interest in cancer research. Choline is incorporated into membrane phospholipid in the form of phosphatidylcholine through the multistep Kennedy pathway. Phosphatidylcholine is one of the major lipid components of plasma membranes in mammalian cells and is essential for membrane structural stability and cell proliferation. Following its transport into the cell, choline undergoes ATP-dependent phosphorylation to form phosphocholine, a reaction catalyzed by choline kinase. High levels of choline uptake and increased choline kinase activity relative to normal tissues have been reported in various cancers including brain tumors (Fulham et al. 1992). This has motivated the development of choline based PET imaging for noninvasive evaluation of gliomas.

Shinoura et al. (1997) were the first to use choline as a PET tracer of brain tumor imaging. They evaluated 20 patients with brain tumors using [11C]choline PET. Progressive uptake of [11C]choline was observed in brain tumors, while uptake by surrounding normal cerebral cortex was 10-fold lower. Later, Ohtani et al. (2001) compared [11C]choline-PET with [18F]FDG-PET in 22 patients with histopathologically confirmed benign lesions and brain tumors from grade I-IV. Higher uptake of [11C]choline relative to [18F]FDG was observed in high-grade grade III and grade IV gliomas. Furthermore, [11C]choline was able to detect the extent of tumor better than MRI and could differentiate high-grade from low-grade lesions, but could not differentiate low-grade lesions from benign lesions.

The short half-life of [11C]choline limits the use of this tracer to facilities having an on-site cyclotron. In view of this, a choline radiotracer with a longer half-life is highly desirable. [18F]Fluorinated analogs of choline [18F]FCH are promising options for choline based PET tumor imaging.

DeGrado et al. (2001) first reported brain tumor imaging with [18F]FCH in a patient with previously resected anaplastic astrocytoma. The maximal T/N ratio of 10:1 was attained within 5 min after injection. [18F]FDG -PET revealed a corresponding area of increased [18F]FDG uptake; however, the tumor boundaries were difficult to assess with FDG because of high uptake by normal cortex. Hara et al. (2003) performed studies with [18F]fluoroethylcholine (FECH) in 12 glioma patients. The T/N ratio of [18F]FECH was 10.5- 12 in anaplastic astrocytoma and 13.2-21 in glioblastoma. These ratios were slightly higher

PET Imaging of Gliomas 169

with tumor progression and invasiveness of gliomas (Bello et al. 2001). Therefore, this

The most common integrin-targeting radiopharmaceuticals are radiolabeled RGD containing peptides. Cyclic RGD peptides (cRGD peptides) are preferred over linear RGD peptides due to their higher metabolic stability (Bogdanowich-Knipp et al. 1999). However, radiolabeled cRGD peptides (18F-FB-cRGDs (Chen et al. 2004) and 64Cu-DOTA-cRGDs (Chen et al. 2004)) commonly suffer the drawback of poor tumor retention and high renal and/or hepatic uptake. To improve the tumor imaging properties of these tracers, dimeric (Chen et al. 2004) and tetrameric (Wu et al. 2005) cyclic RGD congeners have been developed. The multimeric cyclic RGD probes showed higher tumor uptake but nevertheless exhibited rapid uptake by liver and kidneys. To decrease uptake in liver and kidneys, modifications such as glycosylation (Schnell et al. 2009) or PEGylation (Chen et al. 2004) have helped to achieve higher uptake in tumors along with decreased uptake in liver and kidney in U87MG glioblastoma models (Chen et al. 2004; Chen et al. 2004; Wu et al. 2005) and in patients with

New developments to integrin imaging are in progress. Recently, a new generation of RGD containing probes have been designed that show better potential for imaging gliomas. The new approach is based on cystine knot proteins or knottins that are relatively stable in physical, chemical and biological environments due to presence of scaffold of disulfidebonded framework and a triple-stranded ß-sheet fold (Kimura et al. 2009). The Knottin family members also possess one or more surface-exposed loops that can tolerate sequence diversity. RGD peptides have been grafted into these surface-exposed loops, while radiolabeling accomplished with conjugation of PET radionuclide, 18F-FB or 64Cu-DOTA. In a U87MG glioblastoma model, a knottin based probe demonstrated rapid and high tumor accumulation, fast clearance from blood and normal organs, and low uptake in the kidney

Increased cellular proliferation is an integral part of the cancer phenotype (Bading and Shields 2008). The primary requirement for cell proliferation is replication of nuclear DNA. Of the 4 nucleotides (adenine, guanine, cytosine and thymidine) required for DNA synthesis, thymidine is the only one that is specific for DNA. In cells, thymidine is derived either *de novo* or through the salvage pathway (Bading and Shields 2008). The *de novo* pathway is not a viable alternative for monitoring DNA synthesis in proliferating cells because the relevant precursors (deoxyuridine, uridine, and uracil) are routed into both DNA and RNA (Bading and Shields 2008). Thus, thymidine salvage pathway is a better choice for indication of proliferation. PET radiotracers of thymidine have been developed, including [11C]thymidine ([11C]TdR) (De Reuck et al. 1999) and 3'-deoxy-3'-fluorothymidine ([18F]FLT). These probes are currently being evaluated for their potential for imaging cellular proliferation in gliomas. The thymidine-based tracers are transported into cells and subsequently phosphorylated by thymidine kinase-1 (TK-1), thereby rendering them trapped within the cell. Since TK-1 activity correlates to a significant extent with the cellular proliferation rate, the PET-measurement of tissue retention of radioactivity is a noninvasive indicator of proliferation. The advantage of using the fluorinated thymidine tracer [18F]FLT over [11C]TdR is twofold. First, replacement of the hydroxy group of

integrin has received attention as a target for imaging probe development.

*de novo* or recurrent GBM (Schnell et al. 2009).

and liver (Miao et al. 2009).

**6. Cellular proliferation probes**

than those obtained with [11C]choline in the same patients. A preliminary study by Kwee et al. (2004) in 2 patients suggested that [18F]FCH uptake was significantly higher in glioblastoma multiforme (GBM) than benign demyelinating disease. Subsequently, Kwee et al. (2007) performed a more extensive [18F]FCH PET study on 30 consecutive patients (14 women, 16 men; age range, 26-79 years) with solitary brain lesions defined by MRI. In this study, the order of SUV and T/N ratios were benign lesions < high-grade gliomas < metastases from distant tumors with appreciable separation of these classes. [18F]FCH is also useful in detecting recurrent GBMs (**Figure 5**).

Pre-clinical studies on the *in vivo* kinetics and metabolism of [18F]FCH and choline in a 9L glioma allograft tumor model showed marked washout from the tumor possibly resulting from the hypoxic nature of these tumors. However, a strong association of [18F]FCH uptake and angiogenesis was found in the C6 glioma xenograft model (Wyss et al. 2007) and increased [18F]FCH uptake was observed in a multidrug resistant U87MG glioma tumor model (Vanpouille et al. 2009).

Fig. 5. [18F]FCH uptake in recurrent GBM. PET/CT (left) and [18F] FCH-PET (right) image shows a 6 mm focus of increased [18F]FCH uptake along a right frontal lobe resection cavity. This lesion was noted to increase in size on serial brain MRI consistent with the diagnosis of recurrent tumor. A post-craniotomy defect is evident on the PET/CT image. [18F] FCH-PET is potentially advantageous for imaging brain tumors such as GBM given the low amounts of physiologic cerebral [18F]FCH uptake. *Image Courtesy of Dr. Sandi A. Kwee, MD, Nuclear Medicine Department, Queen's Medical Center, Honolulu, HI, USA.*


*Proceeding Paper* **Characterization of a Coal Shale from Marcel Mining as Raw Material for Geopolymer Manufacturing †**

**Kinga Korniejenko 1,\* , Beata Figiela 1 , Kinga Pławecka 1 , Alperen Bulut 2 , Baran ¸Sahin 2, Göksu Aziza ˘gao ˘glu 2 and Michał Łach 1**

**Abstract:** Implementing the idea of a circular economy is one way to reduce carbon emissions and, at the same time, the consumption of natural resources. The use of mining waste as a raw material helps meet the growing demand for construction materials with a smaller carbon footprint. The article shows the possibility of using a coal shale from Marcel mining to create new eco-friendly materials, geopolymers. The main aim of the presented research includes characteristics of raw material and synthesis of geopolymers based on mining waste (coal shale from Marcel mining) and next, investigations of the obtained materials. Geopolymer was prepared using a sodium activator plus milled and calcinated precursor materials. In this study, the following research methods were used: particle size analysis, XRD analysis, mechanical properties tests (compressive and bonding strength), and microstructure analysis—scanning electron microscopy. The results show potential for the extraction of waste from the Marcel company to obtain material for advanced applications in the geopolymerization process. The material had a compressive strength of 12.7 MPa and a bending strength of 3.4 MPa, which makes it possible for use in construction applications such as various types of foundations, walls, columns, lintels, terraces, stairs, ceilings, small building elements, and small architecture. The proposed process could be a promising alternative to current methods of managing waste rock, in particular hard coal mining.

**Keywords:** geopolymer; coal shale; mining waste; industrial by-products; circular economy


*4.3.6 Sleep*

Patients with advanced stage heart failure often experience insufficient and poor-quality sleep because of periods of pulmonary fluid overloading, resulting in orthopnoea, paroxysmal nocturnal dyspnoea, and nocturia [36].

Respiratory disorders during sleep affect >50% of patients with low ejection fraction. When heart failure becomes more severe, there is an evident increase in the prevalence of Cheyne-Stokes respiration with central sleep apnoea [characterised by a ventilation pattern expressed with hypocapnia associated with hyperventilation]. Another main type of sleep disorder often seen in heart failure patients is obstructive sleep apnoea [OSA]. OSA is especially common if the patient is overweight, has diabetes, and has a large neck circumference, or if there is retro or prognathism. In addition, OSA is accepted as one of the comorbidities contributing to low ejection fraction.

The determination and recording of factors affecting sleep, such as changes in sleep and activity, diet, and drugs used, is important for the provision of sleep hygiene**.**


**Acronyms**

identify asymptomatic malaria carriers through active case detection (ACD). The BMGF funded the development of a highly sensitive rapid diagnostics test (hsRDT), which is specific for Pf [83]. It is much more sensitive than standard rapid diagnostic tests (RDT), but not as sensitive as PCR (which is probably not necessary) [84, 85]. Alere (www.alere.com, now Abbott) has made these hsRDTs commercially available for \$0.95/each; approvals in GMS are in process. The same company also markets a malaria antibody-based RDT for both Pf and Pv [86]. The usefulness of these new tools can be rapidly demonstrated during scale-up; the hsRDT will hopefully obviate the need for mass drug administration [87]. Both of these new RDTs should facilitate defining risk populations.

If the package of available tools does not rapidly stop malaria transmission, other more aggressive tools can be added as they become available [85]. Currently available drugs are problematic for prophylaxis—primaquine and doxycycline require daily dosing; doxycycline has already been widely used along the Vietnam border—its current efficacy is unknown. Mefloquine is poorly tolerated and its use for prophylaxis may accelerate its demise. Tafenoquine [88, 89] and RTS,S malaria vaccine [90] should be accelerated to play a role for prevention in the region.

The last remaining parasites will be the most drug-resistant—alternative regimens are urgently needed. Tafenoquine [91] (unpublished observations for Pf), azithromycin and methylene blue [92–95] are currently under recognized, but could also play a role in combination treatment when no alternatives remain, which may be very soon. New regimens should be urgently evaluated; all should be seven days, as some or all of the drugs will have short half-lives. With sevenday regimens, adherence will be very challenging. Hospitalization with appropriate incentives should become the norm to achieve very high treatment adherence in the near future, including the current three-day regimens in areas where outpatient treatment monitoring is not successful.

Emerging incurable malaria in the GMS is a grave public health threat. We call for targeted, immediate decisive action by international and host country governments to establish mission leadership, enough authority, respect, and expertise at each operational level. Security forces must be engaged. Commitment and a real sense of urgency will be most effectively achieved with a PHEIC. We call on the major donors (BMGF, United States Agency for International Development, ADB, the US military) and other philanthropists/donors to fulfill the need for efficient funding. In this chapter, we have proposed the methodology to achieve elimination of the nearly incurable malaria parasites "East of Bangkok" near the WHO target of 2020 [24]. With the currently available tools, each partially effective, but when used together with smart phone-based quality monitoring of appropriate use in the actual transmission areas—we believe the mission can be accomplished near the target date. We call for the critical actions, focusing resources to where they will have most impact to help prevent the next pandemic.

We wish to thank NIMPE and Phu Yen Provincial Health leadership and staff for planning executing the work described in Vietnam (especially Professor Duong Thanh Tran, Dung

**6. Conclusion/call to action**

66 Towards Malaria Elimination - A Leap Forward

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## *Edited by Thomas F. Heston*

The medical specialty of primary care addresses the basic and fundamental healthcare needs of individuals, the family, and the larger community. Its reach starts at preconception and extends to global health and medical issues. Primary care issues include chronic medical problems, surgery, and community-wide health threats such as worldwide global pandemics, terrorism in all of its forms, and domestic violence. This book reviews eight topics including chronic medical issues like chronic fatigue syndrome, the response of primary care clinicians to global pandemics, and how patients and physicians are symbolized in comics. From top experts in the field, this book will improve your ability to practice primary care and to appreciate the broad demands placed upon primary care clinicians.

Published in London, UK © 2021 IntechOpen © Angela Sutton / iStock

Topics in Primary Care Medicine

Topics in

Primary Care Medicine

*Edited by Thomas F. Heston*


**5. Conclusions**

234 Ectopic Pregnancy – Modern Diagnosis and Management

stabilized by the measures such as Foley balloon tamponade, large vessel ligation, or angiographic embolization. In the clinically stable cases, measures are categorized into three groups by ultrasound examination. 1) Systemic MTX is recommended at less than 9 weeks of gestation with no cardiac activity. 2) Intra-amniotic potassium chloride with systemic MTX is chosen at 9 to 12 weeks or less than 9 weeks with cardiac activity. 3) Primary hysterectomy is indicated at more than 12 weeks. That is, at an advanced gestational age or

In our case, serum β-hCG levels were over 10,000 IU/L and ultrasound examination showed positive fetal cardiac activity. Therefore, systemic MTX administration was chosen to treat

With regards to MTX administration, Barnhart pointed out that mainly two protocols were used for medical management for unruptured ectopic pregnancy: "single dose" regimen and "multidose" regimen. MTX can be given using a "multidose" regimen of 1mg/kg intramuscularly, alternating with 0.1 mg/kg of leucovorin intramuscularly for up to four daily doses of each drug[33]. Alternatively, methotrexate can be administered using a "single dose" method, based on body surface area, at 50 mg/m2 without the need for leucovorin rescue. It is concluded that "single dose" regimen is milder than in side effect but has higher failure rate than "multidose" regimen. This "multidose" regimen has been used for a long time as MTX-leucovorin rescue regimen for the patients with low-risk gestational trophoblastic disease and it has slightly lower remission rate than 5-days MTX regimen[34]. Five-days MTX regimen, in which MTX is administered in a dose of 0.4mg/kg intramuscularly for five days with cycles repeated every 14 days, is another protocols that is frequently used for low-risk gestational trophoblastic disease[35]. With above consideration, we applied 5 days MTX regimen for our patient. The serum β-hCG level fell slowly to 4 mIU/mL before surgery, just as following the normal regression curve of β-hCG after molar evacuation[36]. However, it became undetected at the next day after surgery. According to Kamrava, the serum clearance of hCG by radioimmunoassay may take place at least up to 24 days after surgery if the lesion can be removed completely and the initial tilter of hCG is a significant factor in determining the length of time that it can be detected in the serum postoperatively[37]. In this means, the surgical excision of the trophoblastic tissue was

Although the surgery in our case was considered to be fairly long, i.e., 6 h (it was initiated as an emergency operation, late at night (21:00), due to continuous bleeding from the vagina), partial trachelectomy could be completed in less time upon improved techniques. In consideration of the new treatment option of partial trachelectomy, the treatment algorism should be revised to include more chances to preserve fertility, especially in difficult cases. Indications for partial trachelectomy include: 1) when measures for massive hemorrhage such as Foley balloon tamponade, large vessel ligation, and/or angiographic embolization are ineffective; 2) when MTX is ineffective indicating primary hysterectomy for cases at gestational age > 12 weeks; or 3) when systemic MTX plus intra-amniotic potassium is ineffective as a complete cure and additional surgical measures like curettage or suction evacuation are necessary. However, this surgical option might be accompanied with various risks, including relapse, premature delivery, and surgical wound rupture, although the risk should be less than that for radical trachelectomy indicated for the increasing number of cases of cervical cancer patients. Further studies are needed to determine the benefits and risks of partial trachelectomy before establishing it as a treatment for patients with cervical

after treatment failure, pregnancy should be terminated by hysterectomy.

considered to be complete with this procedure.

ectopic pregnancy.

the patient.

In conclusion, "partial trachelectomy" is a new procedure that shares many similarities to previous procedures. It differs in the following two respects: 1) exact ligation or cut of the descending branch of the bilateral uterine artery and 2) excision of the spindle shapedcervical wall of the implantation site under direct vision by temporally detaching the vaginal wall and cervix. This procedure preserves fertility under any condition although with more risk of complication for future pregnancies compared to previous methods in which fertility preservation is not always successful. However, it is less invasive compared to radical trachelectomy which is a common method of fertility preservation for cancer patients with non-cervical pregnancy.


**9. Conclusions**

As a precise and reliable tool in the field of ophthalmic surgery, fs-laser technology has evolved over the past few decades. Fs-laser-assisted cataract and corneal surgery have reached a high standard worldwide, despite the fact that some applications are still in the early stages of development. These procedures have been made safer and more effective by the use of fslaser technology, which has opened the door to new surgical approaches.


**5. Discussion**

In this paper, we introduced an intrinsic approach to measuring gender bias on contextualized embeddings by using gender polarity: an existing bias metric that measures how related an embedding of a word is to a specific gender. This metric has previously been applied on contextualized embeddings by first mapping them to the Word2Vec embedding space. We contribute by first detecting a stable gender direction in T5's embedding space and then computing gender polarity distributions for the various embeddings, instead of single values, for each word. The results of this approach are consistent with those of an extrinsic approach that we also followed; we evaluated T5's and mT5's outputs in terms of how bias can be propagated to the downstream task of semantic text similarity.

Our results indicate that higher status professions tend to be more associated to the male gender than the female gender. We also compared Swedish with English as well as various model sizes and found that our methods find less bias associated with gender in the Swedish language, though we note that the detection method itself may be more sensitive to bias in English. Additionally, we find that larger sizes of the models can lead to an increased manifestation of gender bias. This finding suggests that the embedding dimensionality might be proportional to the extend to which biases will be successfully encoded in the embedding vectors.

The consistency of the results between the intrinsic and extrinsic approach might be a positive indicator that deriving a stable gender direction in a Transformer model's embedding space is feasible and can lead to valid results. This is a simple, yet powerful idea, which if supported by further research, can offer a solid basis for effective debiasing in Transformer models.

### **6. Ethics Statement**

It has been shown that changes in stereotypes and attitudes towards women and their participation in the workforce can be quantified by tracking the temporal dynamics of bias in word embeddings [20]. Furthermore, it has been observed in various use cases that models might marginalize specific groups in the way they handle downstream tasks, establishing a behavior similar to that of a stereotypically biased conduct [21–26]. To responsibly direct actions that will combat this problem, it is of crucial importance that we find reliable ways of detecting and quantifying it, which is what we aim for in this work. A reliable way of bias detection could be the touchstone of developing effective bias mitigation techniques, which could practically contribute to the pursuit of a more fair representation of different races and genders by the models. Such a course of action complies with the fifth and tenth goal regarding "gender equality" and "reduced inequalities" respectively, as defined in the 17 Sustainable Development Goals (https://sdgs.un.org/goals, accessed on 12 December 2021) set by the United Nations General Assembly and intended to be achieved by the year 2030. More specifically, this work is aligned with sub-goal 10.2 that is about empowering and promoting "the social, economic and political inclusion of all, irrespective of age, sex, disability, race, ethnicity, origin, religion or economic or other status" (https://sdgs.un.org/goals/goal10, accessed on 12 December 2021). This work is also aligned with sub-goal 5.1 that is about ending "all forms of discrimination against women and girls everywhere", and sub-goal 5.5, which ensures "women's full and effective participation and equal opportunities for leadership at all levels of decision-making in

political, economic and public life" (https://sdgs.un.org/goals/goal5, accessed on 12 December 2021).

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

**Funding:** This research was funded in part by by VINNOVA, Sweden (project title: Språkmodeller för svenska myndigheter, grant number 2019-02996) and by the Swedish research council under contract 2019-03606.

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

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data that support the findings of this study are openly available at http://ixa2.si.ehu.es/stswiki/index.php/STSbenchmark accessed on 12 December 2021, at https: //github.com/timpal0l/sts-benchmark-swedish accessed on 12 December 2021 and at https:// github.com/Stellakats/Master-thesis-gender-bias accessed on 12 December 2021.

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

**Figure A1.** Average similarity scores per occupation. Model: T5 small.

**Figure A2.** Average similarity scores per occupation. Model: T5 base.

**Figure A3.** Average similarity scores per occupation.

**Figure A4.** Average similarity scores per occupation. Language: English. Model: mT5 small.

 Model: T5 large.

**Figure A5.** Average similarity scores per occupation. Language: Swedish. Model: mT5 small.

**Figure A6.** Average similarity scores per occupation. Language: English. Model: mT5 base.

**Figure A7.** Average similarity scores per occupation. Language: Swedish. Model size: mT5 base.

**Figure A8.** Average similarity scores per occupation. Language: English. Model: mT5 large.

**Figure A9.** Average similarity scores per occupation. Language: Swedish. Model: mT5 large.