Meet the editor

Christian Cuadrado-Laborde received his PhD degree in Physics from the University of La Plata (UNLP, Argentina, 2005), and his Electrical and Electronic Engineering degree from the University of San Luis (UNSL, Argentina, 1998). He is an independent researcher of CONICET (2005), the most important federal research agency in Argentina. He leads the Laboratory of Optics and Photonics in the Institute of Physics Rosario (IFIR, Rosario,

Argentina). He is currently also Full Professor of the Engineering Faculty of the Pontifical Catholic University of Argentina (Rosario, Argentina). He was awarded by the Spanish Ministry of Science with a research fellow position to join the Optical Fiber Laboratory group headed by M.V. Andrés of the University of Valencia (Spain) during 2008–2009. Since then, he has continued collaborating actively with this research group. He has published several research papers in top-tier scientific journals such as *Progress in Optics*, *Optics Letters*, *Optics Express*, *Laser & Photonics Reviews*, *Optics & Photonics News*, etc. His current research interest includes fiber optics applications, photonic signal processing, and mode-locked all-fiber lasers.

**Preface III**

**Chapter 1 1**

**Chapter 2 7** Minimalist Approach for the Design of Microstructured Optical Fiber Sensors

**Chapter 3 23**

**Chapter 4 55**

**Chapter 5 81** Real-Time Particle Radiography by Means of Scintillating Fibers Tracker and

**Chapter 6 95**

**Chapter 7 117** Optical Fibre Long-Period Grating Sensors Operating at and around the Phase

*by Rebecca Yen-Ni Wong, Dora Hu Juan Juan, Morten Ibsen and Perry Ping Shum*

Fiber Bragg Gratings as e-Health Enablers: An Overview for Gait Analysis

*by Maria de Fátima Domingues, Cátia Tavares, Tiago Leite, Nélia Alberto, Cátia Leitão, Carlos Marques, Ayman Radwan, Eduardo Rocon, Paulo Antunes*

*by Domenico Lo Presti, Giuseppe Gallo, Danilo Luigi Bonanno, Daniele Giuseppe Bongiovanni, Fabio Longhitano and Santo Reito*

Review of Liquid-Filled Optical Fibre-Based Temperature Sensing

*by Fintan McGuinness, Gabriel Leen, Elfed Lewis, Gerard Dooly, Daniel Toal*

Introductory Chapter: Application of Optical Fiber for Sensing

*by Christian Cuadrado-Laborde*

Contents

Applications

*and Paulo André*

Residual Range Detectors

*and Dinesh Babu Duraibabu*

Matching Turning Point

*by Jonas H. Osório and Cristiano M. B. Cordeiro*

Distributed, Advanced Fiber Optic Sensors *by Sanjay Kher and Manoj Kumar Saxena*


**Abstract**

Rapid progress of technologies does not only exclusively belong to developed countries nowadays but also spread out to developing countries including Indonesia. There are many Indonesian universities and emerging translational medicine centers that had declared themselves as research centers focusing on to bring science from bench to bedside. Since the outbreak of 2007 Avian Influenza, Indonesia had been starting to accumulate more knowledge and experiences related to biosafety and biosecurity. While Indonesian researchers were focusing on biorisk management of high pathogenic bioagents, students were also being exposed gradually to more sophisticated biological hazards through the utilization of synthetic biology and genetic modifications on their own researches. Nurturing the responsible future generation of scientist whom aware of the ethical, biosafety, biosecurity concerns cannot become more important, considering the possibility of dual use research results, which could bring either prosperity or chaos to the universe.

**Keywords:** biosafety, biosecurity, dual use research of concern


*2.1. The Bristol Context*

Bristol is recognized as one of the most susceptible cities within the top 10 Flood risk areas in the UK [14]. This is mainly caused by the influence of the tidal river "Avon", directly connected to the sea by mean of the "Severn Estuary", where tides have a great effect on the river water depth. This tidal effect is transmitted to a lesser extent to the other rivers that flow into the river Avon. Bristol has undergone severe floods caused by the combination of storm surges and spring tides, but also others provoked by heavy rainfall.

Some great historical floods have occurred in Bristol throughout time. The first example is an historical flood that took place in 1607 when the death of around 2000 people was estimated. A second more recent example took place in 1896 when a tidal flood event caused a 1m water depth in the city center, and in 1968 when a combination of a great rainfall with a river flood event killed 7 people and flooded around 800 properties in the Bristol area. Also, an extreme rainfall event in 2012 caused the flooding of 25 properties due to surface water flooding [14]. All these examples give an idea of the flooding experienced in Bristol and present a real problem that this city has suffered over time.


*3.3. The PEI-linear Demonstrates Broad inhibition of Heterogeneous PRRSV-2 Isolates*

As a chemical reagent, the inhibitory effect of PEI-linear on PRRSV is expected to be broad spectrum. We next tested whether this PEI could inhibit other *PRRSV-2* isolates in MARC-145 cells. Our results showed that the replication of other *PRRSV-2* isolates (JXA1, GD-HD, and VR-2332) was significantly inhibited by PEI in a dose-dependent manner (Figure 3A–C). Moreover, the progeny virus from cell culture supernatants were titrated. Based on our data, it appears that PEI-linear demonstrated the strongest inhibition to PRRSV-2 VR-2332 for at least two Log10 reductions of infectious viral particles (Figure 3D). Notably, the NADC30-like isolate replicated poorly in MARC-145 with a viral titer below 105 TCID50/mL (Figure 3D). The inhibitory effect of PEI against different PRRSV strains was not uniform as the titers of certain viral isolates such as JXA1 were higher than the others. Taken together, these data showed that PEI-linear could effectively inhibit several PRRSV-2 isolates tested in MARC-145 cells.

**Figure 3.** PEI demonstrates broad inhibition of heterogeneous *PRRSV-2* isolates in MARC-145 cells. MARC-145 cells were incubated with a mixture containing 1 MOI of PRRSV JXA1 (**A**), GD-HD (**B**) and VR-2332 (**C**) mixed with the 40 kDa linear PEI at the indicated concentrations for 1 h. Then the cells were washed and cultured for an additional 24 h. Replication of PRRSV was determined in Western blot with Mab-6D10 against N protein. (**D**) PRRSV yields in MARC-145 cells infected with the mixture of different PRRSV virus strains at 0.1 MOI and PEI-linear (6 μg/mL). The mixture was removed and replaced by a fresh medium. The cells were incubated for 24 h before the cell culture supernatant was harvested for titration. All experiments were repeated at least three times, and the data were presented as the mean ± SD, which is further subjected to Student's t-test. Significant differences between indicated groups were marked by "\*" (*P* < 0.05) and "\*\*" (*P* < 0.01).


 The use of fat transfer to replace volume or camouflage soft tissues is an increasingly popular method in craniofacial surgery and facial esthetics. Craniofacial malformations undoubtedly have a certain psychosocial effect. Children of early age are particularly vulnerable to comments, teasing, and harassment related to their appearance; therefore, improving the facial image is of great importance. We believe that volumetric lipoinjection represents an excellent alternative to obtain greater facial esthetic harmony, which directly increases patient self-esteem in children and adults.

**Keywords:** adipose stem cells, lipoinjection, lipofilling, craniofacial malformations, facial profiling


**5. Conclusion**

proportions found in the present study cannot directly be compared to the weights determined in [79], which are based on mere distance-related cues, those interfering factors had to be experimentally dissociated and, where applicable, included in

There were some additional results on factors and measures which were not

a. Both egocentric distance and room size mean estimates, regardless of whether based on acoustic, visual or acoustic-visual stimuli, were obviously lower for speech than for music (though this was not hypothesized or tested, see 2.7). Hence, there is a reason for hypothesizing an influence of content type. This might be due to differences between music and speech regarding, e.g., the bandwidth and energy distribution of the frequency spectra carrying spatial information, perceptual filtering and processing, receptiveness, and/or experiential geometric situations (non-mediatized speech is normally

received from lower distances and within smaller rooms than non-mediatized

b. Both the non-significant interaction effect and the particular mean estimates in the experiment according to the conflicting stimulus paradigm indicated that acoustic-visual (mainly spatial) congruency of the stimulus properties did not lead to minimum, maximum or especially accurate mean estimates.

congruency might play a greater role by contrast with a greater range of the incongruencies (e.g., further-away sound sources) or a greater number of

c. Egocentric distance mean estimates were most accurate under the acousticvisual (music) and visual (speech) condition; the room size mean estimates, which were generally inaccurate, likely due to the lack of the visual rendering of the rooms' rear part, were most accurate under the acoustic condition. In

overestimations of the geometric properties (*D*^ /*D* 6¼ 1) under the acousticvisual condition, neither an *increasing* underestimation nor an *increasing*

d. Looking at the conflicting stimulus paradigm, the minimum and maximum mean estimates of both source distance and room size did not consistently correspond to the minimum and maximum physical distances and sizes. *Perceived source distance* and *perceived room size* were each influenced by the physical source distance, the physical room size and potentially other

e. Because mean estimates based on purely acoustic stimuli were generally

higher in low-absorbent than in high-absorbent rooms (cf. [18]), the range of mean estimates introduced by the factor *Domain* was also generally smaller in low-absorbent rooms. This caused the respective mean estimates under the

contrast to previous studies [32, 36], regardless of general under- or

overestimation was conspicuous, rather *D*^ /*D* ≈ const.

properties of the virtual scenes.

**118**

This observation is not apt to constitute a general hypothesis, since

incongruent properties (e.g., including incongruent content).

physical-perceptual models of auditory-visual distance perception.

*Advances in Fundamental and Applied Research on Spatial Audio*

**4.5 Additional observations**

explicitly asked for by the RQs:

music).

The influence of the presence as well as of the properties of acoustic and visual information on the perceived egocentric distance and room size was investigated applying both a co-presence and a conflicting stimulus paradigm. Constant music and speech renditions in six different rooms were presented using dynamic binaural synthesis and stereoscopic semi-panoramic video projection. Experimentation corroborated that perceptual mean estimates of geometric dimensions based on only visual information considerably exceeded those based on only acoustic information in general. However, the perceptual mode as such (single- vs. multi-domain stimuli) altered the perceptual estimates of geometric dimensions: Under the acoustic-visual condition with acoustic-visually congruent stimuli, the presence of visual geometric information was generally given more weight than the presence of acoustic information. While the egocentric distance estimation under the acousticvisual condition did not tend to be compressed for music, it did for speech. When only acoustic stimuli were available, the greater amount of acoustic information provided by low-absorbent rooms appeared to be perceptually exploited to improve the accuracy of room size perception. Within the multi-domain mode of perception involving 30 acoustic-visually incongruent and 6 congruent stimuli, auditory-visual estimation of geometric dimensions in rooms relied about nine-tenths on the variation of visual, about one-tenth on the variation of acoustic properties, and negligibly on the interaction of the variation of the particular properties. Both the auditory and the visual sensory systems contribute to the perception of geometric dimensions in a straightforward manner. The observation of generally lower estimates for speech than for music needs to be corroborated and clarified. Further experimentation dissociating the factors source distance, room size, and acoustic absorption (all else being equal) is needed to clarify their particular influence on auditory-visual distance and room size perception.


**3.4 Patent ductus arteriosus and aortopulmonary window**

122 Echocardiography – In Specific Diseases

overload. The MR can pass the primum ASD and results in LV to RA shunt, RA volume overload, and pulmonary overcirculation. In patients with complete AVSD, the presence of concomitant atrial and ventricular shunting can cause increased shunt flow. Pulmonary hypertension, secondary pulmonary vascular change, and increased pulmonary vascular resistance (PVR) can occur thereafter. The hemodynamic changes are affected by the magnitude and direction of shunt flow. There may be different directions of AV valve

The mid-esophageal four-chamber view of intraoperative TEE can demonstrate the defect of inferior part of atrial septum. Secundum ASD or patent foramen ovale (PFO) can be present in some patients. The broad-base MR jet not originating from the coaptation may suggest the presence of a cleft mitral valve (Figure 8). Cleft mitral valve may be demonstrated in transgastric basal short-axis view. Besides, the presence of ventricular shunting, sizes of both ventricle, ventricular function, magnitude and direction of AV valve incompetence, degree of AV valve straddling, presence of LVOT obstruction, degree of pulmonary hypertension, and associated cardiac anomalies must be evaluated preoperatively. The postoperative TEE exam should include the evaluation of ventricular function, AV valve competence, and the presence of residual shunt (Cohen et al., 2007). Because valvular regurgitation is quite pressure and load dependent, it is important that we take patient's volume status and cardiac contractility into consideration when comparing preoperative and postoperative regurgitation severity. If prosthetic valve is replaced, it is important to

regurgitation: LV-to-left atrium (LA), RV-to-RA, LV-to RA, or RV-to-LA.

check the function of prosthetic valve and the presence of paravalvular leak.

Fig. 8. Partial atrioventricular septal defect. The mid-esophageal four-chamber view demonstrates a primum atrial septal defect (atrial) and mitral cleft (double arrow) with

severe mitral regurgitation.

PDA is a postnatal communication between the main pulmonary trunk and descending thoracic aorta due to persistent patency of fetal ductus arteriosus (Schneider & Moore, 2006). Shunt flow is determined by diameter of PDA and the pressure gradient. The preoperative TEE can demonstrate the shunt flow in the ascending aorta short-axis view (Figure 9). The size of left-side chambers, ventricular function, valvular regurgitation, degree of pulmonary hypertension, and associated cardiac anomalies must also be evaluated. The postoperative TEE exam can be used to detect the presence of residual ductal flow.

Aortopulmonary defect, also known as aortopulmonary (AP) window, is a defect between ascending aorta and pulmonary artery. Without treatment, pulmonary system will be overloaded due to left to right shunt, and eventually develop pulmonary vascular occlusive disease. A significant portion of the patients have other associated cardiac anomalies. Preoperative TEE can detect a shunt between ascending aorta and PA (Figure 10). Evidence of pulmonary hypertension, ventricular function and size, defect size and shunt pressure gradient can be measured by intraoperative TEE. Surgical treatment usually involves aorta incision, defect visualization, and a patch is sutured to close the defect over the aortic side. The post-repair TEE exam should detect the presence of residual shunt, valvular competence, and ventricular function.

Fig. 9. The upper esophageal aortic arch long-axis view demonstrates the patent ductus arteriosus (arrow) connecting aortic arch and left pulmonary artery. Ao, aorta.

Intraoperative Transesophageal Echocardiography for Congenital Heart Disease 125

After repair, truncal valve function, residual intracardiac shunt and RVOT patency can be examined with color Doppler. Monitoring of ventricular function is important, because coronary artery may be compromised during pulmonary artery resection, RV-PA conduit reconstruction, and reimplantation of coronary arteries. Pulmonary hypertensive crisis and low cardiac output are potential threats for patients undergoing repair. RV function and severity of TR demonstrated in TEE exam can give anesthesiologist a guide for patient

Fig. 11. The mid-esophageal long-axis view shows a truncal vessel overrides the left

Postoperative TEE gives a direct evidence of anatomic site patency and LV function.

ventricle (LV) and right ventricle (RV) and gives rise to aorta and pulmonary artery (arrow).

Coarctation of aorta (CoA) is characterized by narrowing of aortic lumen due to thickening or infolding of aortic media (Rosenthal, 2005). Interrupted aortic arch (IAA), on the other hand, is complete discontinuity between two parts of aortic arch. These lesions lie closely to PDA or ligament arterioum. In patients with CoA, the defect can be isolated, or associated with VSD or other complex cardiac disease. The LV afterload is increased in patients with CoA. The site and extent of the stenosis may be seen in upper esophageal level during TEE exam (Figure 12). However, preoperative TEE exam can offer valuable information for other associated anomalies, such as biscupid aortic valve, Shone's complex, and VSD. Surgical treatment includes resection of stenotic area with end-to-end anastomosis, extended resection with primary anastomosis, subclavian flap aortoplasty, and patch augmentation. Some patients have balloon angioplasty and stent insertion in intervention units.

management.

Ao, aorta; PA, pulmonary artery.

**3.6 Coarctation of aorta and interrupted aortic arch**

Fig. 10. Aortopulmonary window as a defect (arrow) between ascending aorta and main pulmonary artery. Ao, aorta; PA, pulmonary artery.

#### **3.5 Truncus arteriosus**

Truncus arteriosus is caused by failure of truncal ridge and aortopulmonary septum to develop, forming aorta and PA. There is a single great vessel arising from a common semilunar valve, and a VSD. The truncal valve can have variable cusps, and valvular incompetence is not uncommon. Further classification is dependent on the existence of truncal septum, and the take-off position of pulmonary arteries. The VSD is caused by failure of conal septum to develop and rotate. It is usually large, non-restrictive, with superior border adjacent to truncal valve. PA is usually of normal size, but stenosis at origin site or diffuse hypoplasia may happen. Other common concurrent cardiac defects include right aortic arch, PDA, persistent left-sided SVC, ASD, and anomalous subclaivan artery.

Surgical repair encompasses separation of branched PA from truncus vessel, establishment of RV-PA continuity by RVOT reconstruction or RV-PA conduit, VSD closure, and repair of associated anomalies. Due to variable coronary anatomy, separation of PA from truncal vessel should be done with care. Mild to moderate truncal valve regurgitation is often tolerated, and will improve over time. However, severe regurgitation is a poor indicator for long term survival. If the truncal valve is severely incompetent, valve replacement should be considered.

Intraoperative TEE should focus on truncal valve morphology and function, anatomy of the main and branched pulmonary arteries, size and position of the intracardiac shunting, AV valve competence, ventricular function and the associated cardiac abnormalities (Figure 11).

Fig. 10. Aortopulmonary window as a defect (arrow) between ascending aorta and main

Truncus arteriosus is caused by failure of truncal ridge and aortopulmonary septum to develop, forming aorta and PA. There is a single great vessel arising from a common semilunar valve, and a VSD. The truncal valve can have variable cusps, and valvular incompetence is not uncommon. Further classification is dependent on the existence of truncal septum, and the take-off position of pulmonary arteries. The VSD is caused by failure of conal septum to develop and rotate. It is usually large, non-restrictive, with superior border adjacent to truncal valve. PA is usually of normal size, but stenosis at origin site or diffuse hypoplasia may happen. Other common concurrent cardiac defects include right aortic arch, PDA, persistent left-sided SVC, ASD, and anomalous subclaivan

Surgical repair encompasses separation of branched PA from truncus vessel, establishment of RV-PA continuity by RVOT reconstruction or RV-PA conduit, VSD closure, and repair of associated anomalies. Due to variable coronary anatomy, separation of PA from truncal vessel should be done with care. Mild to moderate truncal valve regurgitation is often tolerated, and will improve over time. However, severe regurgitation is a poor indicator for long term survival. If the truncal valve is severely incompetent, valve replacement should be

Intraoperative TEE should focus on truncal valve morphology and function, anatomy of the main and branched pulmonary arteries, size and position of the intracardiac shunting, AV valve competence, ventricular function and the associated cardiac abnormalities (Figure 11).

pulmonary artery. Ao, aorta; PA, pulmonary artery.

**3.5 Truncus arteriosus**

artery.

considered.

After repair, truncal valve function, residual intracardiac shunt and RVOT patency can be examined with color Doppler. Monitoring of ventricular function is important, because coronary artery may be compromised during pulmonary artery resection, RV-PA conduit reconstruction, and reimplantation of coronary arteries. Pulmonary hypertensive crisis and low cardiac output are potential threats for patients undergoing repair. RV function and severity of TR demonstrated in TEE exam can give anesthesiologist a guide for patient management.

Fig. 11. The mid-esophageal long-axis view shows a truncal vessel overrides the left ventricle (LV) and right ventricle (RV) and gives rise to aorta and pulmonary artery (arrow). Ao, aorta; PA, pulmonary artery.


**Acknowledgements**

*Xmin* Minimum value of variable *Xi*

*NMAE* Normalized Mean Absolute Error *NRMSE* Normalized Root Mean Square Error

*NMBE* Normalized Mean Bias Error

*Sub-section 4.2*

*N (*μ *\_ ;* σ

*qi '*

> *pi '*

*AFlSlb*

*AFlSF2*

*FreTF2*

*Sub-section 5.1*

*AFlCNl, AFlCNop, AFlCNq,*

*AFlT31, AFlT32, AFlSF1,*

*FreSF1, FreSF2, FreTF1,*

*CVRMSE* Coefficient of Variation of the Root Mean Square Error

*N (*μ*;* σ*)* Normal distribution with mean μand standard deviation σ

*f (x)* Probability density function (pdf) of a random variable *X* Φ*(x)* Cumulative distribution function (cdf) of a random variable *X*

σ*min* Standard deviation equals to half the interval in which a desired μ

*x0, x1, …, xL L* + 1bounds of the *L* intervals of a Interval Discrete Chance node of a BN

*, qi* Probability of interval *i*of a non-periodic discrete node (not normalized and normalized

*, pi* Probability of interval *i*of a periodic discrete node (not normalized and normalized,

Air flows in station's rooms named as CNl, CNop, CNq, Slb

Air flows in tunnels TF1 and TF2 and in station fan ducts SF1 and SF2

Frequencies that drive the two fans in the station and the two fans in the tunnels,

\_

and standard deviation σ

\_

\_ falls

*\_)* Desired distribution with mean value μ

respectively)

respectively)

respectively

*ACOPL3* Air changes per hour

*WiSMet* Outdoor wind speed *WiDMet* Outdoor wind direction

*Ei* Prediction error at time *i AEi* Absolute error at time *i S Ei* Squared error at time *i PEi* Percentage error at time *i MAE* Mean Absolute Error *RMSE* Root Mean Square Error

*K* Number of samples in a validation data set

34 Dynamic Programming and Bayesian Inference, Concepts and Applications

This work is part of the EU-funded research SEAM4US. Also, we are very grateful to our colleagues Engs. Roberta Ansuini and Sara Ruffini, who helped us develop the models.


*2.2. Sample Handling*

Soil samples were collected on the farm area (samples 1–7A). Six sampling locations, three on each of the two sides of the poultry house, were selected by measuring 1, 10, and 50 m from the longer wall. One sample was collected near the litter storage place. Aside from the samples in the area of direct impact of the poultry house, reference samples were taken (Figure 1). The reference sample 1B was taken at a distance of 450 m in a straight line to the North East. The references sample 1C was taken at a distance of about 1000 m in a straight line to the East. Samples were taken twice (in March, samples suffix M, and in July samples suffix J) to check for potential seasonal variation, in both cases, about 5 weeks after the poultry house was settled.

Using a shovel, about 1 L of soil was collected from each point at a depth of about 20 cm. In each case, the collected soil material was transported to the laboratory and stored in glass containers at 4 ◦C. Before sample preparation, each sample passed through a 1.5 mm-mesh sieve (to remove roots and stones) and was freeze-dried using the Scanvac CoolSafe 110-4 PRO, LyoAlfa (Telstar, Denmark).

For microorganisms' determination in soil samples, the samples were collected into sterile plastic containers. The samples were stored at 10 ◦C until processing, which was done within 3 days after samples collection.


*Article* **Chemical Composition and Optimization of Liquefaction Parameters of** *Cytisus scoparius* **(Broom)**

**Luísa Cruz-Lopes 1,2,\*, Daniela Almeida 1 , Yuliya Dulyanska 2 , Idalina Domingos 2,3, José Ferreira 2,3 , Anabela Fragata 4 and Bruno Esteves 2,3**

**Abstract:** Invasive plants spread in such a way that they are threats to native species and to biodiversity. In this context, this work aims to determine possible valorizations of Scotch Broom *Cytisus scoparius* (L.) Link. This species harvested in the Viseu region was used in the present study. The eco-valorization of these renewable resources was made by conversion into liquid mixtures that can later be used in the manufacture of valuable products. For a better understanding of the results obtained, a chemical characterization of the *Cytisus scoparius* branches (CsB) was made. The ash content, extractives in dichloromethane, ethanol and water, lignin, cellulose and hemicellulose of the initial material were determined. Liquefaction was made in a reactor with different granulometry, temperatures and time. Results show that Broom is mainly composed of cellulose (36.1%), hemicelluloses (18.6%) and lignin (14.6%) with extractives mainly soluble in ethanol, followed by water and a small amount in dichloromethane. Ashes were around 0.69%, mainly composed of potassium and calcium. Generally, smaller size, higher solvent ratio, higher temperature and higher time of liquefaction lead to higher liquefaction. The highest percentage of liquefaction was 95% which is better than most of the lignocellulosic materials tested before.

**Keywords:** *Cytisus scoparius*; chemical composition; liquefied; optimization; eco-valorization; agro-industrial residues

## **1. Introduction**

Many plants that surround us have not always existed in our territory; they came from other places brought by man from their native habitat. Certain species remain only in places where they have been embedded with native species in a stable way, but others prosper rapidly without the support of man, expanding their populations. These are called invasive plants. The proliferation of these species promotes environmental changes and economic damage so that they can be a threat to natural ecosystems, food production, human health and the economy itself [1]. Therefore, Broom, also called Scotch broom or English broom (*Cytisus scoparius* (L.) Link), is an example of an invasive plant.

In Portugal, communities are dominated by shrubs of the genera *Cytisus, Genista*, *Adenocarpus* and *Retama*. In accordance with Costa et al. [2], the area of occupation of the class *Cytisetea scopario-striati* has increased in recent decades, mainly due to the abandonment of agricultural land. Its development in the Iberian Peninsula resulted in fragmented landscapes, determining spatial patterns of richness, composition and specific abundance or the periods of regression of climatic forests [2]. The class *Cytisetea scopario-striati* develops well on siliceous, poor on bases, non-hydomorphic soils and presents its greatest evolution

**Citation:** Cruz-Lopes, L.; Almeida, D.; Dulyanska, Y.; Domingos, I.; Ferreira, J.; Fragata, A.; Esteves, B. Chemical Composition and Optimization of Liquefaction Parameters of *Cytisus scoparius* (Broom). *Forests* **2022**, *13*, 1772. https://doi.org/10.3390/f13111772

Academic Editor: Antonios Papadopoulos

Received: 22 September 2022 Accepted: 20 October 2022 Published: 27 October 2022

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

**Copyright:** © 2022 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/).

and diversity in the west of the Iberian Peninsula in the Atlantic and Ibero-Atlantic Mediterranean provinces [2]. According to the national forest inventory, forests represent 40% of Portugal's mainland, which is equivalent to almost 3.5 million hectares, 1 million more hectares than agriculture. The forests with the highest territorial expression are eucalypts (*Eucalyptus globulus* Labill) (26%), cork oak (*Quercus suber* L.) (23%) and pine (*Pinus pinaster* Ait.) (22%), and the invasive species represent 0.4% [3,4].

*Cytisus scoparius* can be found in almost all of Europe and Macaronesia. It was introduced in North America, Australia and South Africa. It is common in bushes, scrubs and riparian and the edge of woods and paths. It is used as a medicinal plant, in agroforestry management, as fuel and in the manufacture of outdoor brooms [5]. *Cytisus scoparius* is a shrub 1 to 2 m high. The stem is green, angled, striated longitudinally and hard, with consistent and flexible branches, usually with five well-defined streaks in an inverted V-shape. The space between the stretch marks is greater than their width. This plant is known to have several antioxidant compounds such as flavones, isoflavones, flavonols and carotenoids [6–8].

The emergence of liquefaction techniques at low pressure and temperatures has increased the interest in invasive plants that can be a cheap lignocellulosic alternative to other more valuable materials and constitute an alternative for petroleum-derived fuels. This alternative also has the advantage of contributing to the reduction of greenhouse gas emissions, thus preventing global warming [9]. Liquefaction of moderate to low temperatures has been done using two different types of solvents, phenol [10–13] or polyalcohols [14–18], with basic (NaOH, KOH) or acid catalysis (sulphuric acid, paratuluenosulphonic acid, hydrochloric acid, oxalic acid or phosphoric acid). Phenol is mostly used when the objective is to prepare resins such as epoxy resins since there is a higher content of phenols in the liquefied material [19]. On the other hand, phenol is more toxic than the polyalcohols used and less green since most of the polyalcohols can be obtained from crude glycerol or other non-petroleum materials. Several lignocellulosic materials have been liquefied with polyalcohols such as agricultural wastes, for example, wheat straw [20], cornstarch [21] or rice straw, oilseed rape straw and corn stover [22], forest management residues, such as several woods [15,23,24], barks [16,25,26] or shells [14,27,28] and also some industrial residues such as orange peel [29]. The lignocellulosic material is composed of carbohydrate polymers (cellulose and hemicelluloses), lignin and a small part of other compounds (extractives, salts and minerals). Cellulose and hemicelluloses, which usually account for two-thirds of the dry mass, are polysaccharides that can be hydrolyzed into sugars and, eventually, by fermentation, converted into ethanol. Lignin cannot be used for ethanol production, so that it can be used for thermal energy production by combustion [9]. To improve the knowledge and evaluation of possible applications, the chemical composition of Broom, *Cytisus scoparius*, was determined.

This study intends to determine if *Cytisus scoparius* is a suitable material to produce high quality polyols to be later used for the production of polyurethane foams or adhesives. The knowledge of the chemical composition of the material and the FTIR analysis of initial, liquefied material and solid residue will allow us to understand the chemical changes involved and give some clues on how to improve the liquefaction procedure.

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

#### *2.1. Materials*

The branches of *Cytisus scoparius* (CsB) come from the district of Viseu (São Pedro do Sul). The samples were dried at room temperature, crushed in a Retsh SKI mill (Retsch GmbH, Haan, Germany) and sieved using a Retsch AS200 for 30 min at 50 rpm. Five fractions, >35 mesh (>0.425 mm); 35–40 mesh (0.425–0.450 mm); 40–60 mesh (0.425–0.250 mm); 60–80 mesh (0.250–0.180 mm) and <80 mesh (<0.180 mm) fraction was used for the tests. The fractions obtained were dried in a greenhouse at 100 ◦C for 24 h before each test. The chemical reagents used were analytical-grade reagents.

#### *2.2. Chemical Composition*

The CsB were characterized for their ash content, extractives (in dichloromethane, ethanol and hot water), α-cellulose, lignin and hemicelluloses. The 40–60 mesh fraction was dried at 105 ◦C for at least 24 h and afterward used for the chemical analyses according to Tappi T 264 om-97 [30]. The average chemical composition of each sample was determined in triplicate. The extractives were determined by extraction with different solvents in sequential order of ascending polarity.

The ash content was determined by calcination at 525 ◦C in accordance to Tappi T 211 om-93 [31]. The inorganic composition was determined by ICP after ash wet digestion in a Leco CHNS-932 Elemental Analyzer (St. Joseph, MI, USA).

Extractives were determined by sequential Soxhlet extraction with 150 mL of dichloromethane, ethanol and hot water extractives in accordance with Tappi T 204 om-88 [32]. A total of 10 g of dried material was placed in a filter paper cartridge inside the Soxhlet and refluxed until extractives were removed. Extractions lasted for 6 h for dichloromethane and 16 h for both ethanol and water. Extractive content was determined in relation to the dry material.

Alkaline extraction was done by reflux with 0.3% (*m*/*v*) NaOH under a nitrogen atmosphere.

Lignin was determined by the Klason method in extractive free material. Two hydrolyses were performed, the first in a water bath at 30 ◦C with 72% H2SO4 for 1 h followed by a second with 3% H2SO4 in an autoclave at 120 ◦C for 1 h (according to modified Tappi T 204 om-88) [33]. The insoluble residue was filtered in a G2 glass crucible, washed with warm water and acetone, and dried at 100 ◦C until constant weight. The lignin percentage was determined according to Equation (1).

$$\text{Lignin} \left( \% \right) = \frac{\text{Insolvable residue}}{\text{Dried material}} \times 100 \tag{1}$$

Soluble lignin was determined by measuring the absorbance at 205 nm.

Cellulose *Kürschner–Hoffer* was determined by using 1 g of material that was refluxed with 100 mL of nitric acid: ethanol 20:80 solution for 1 h. This procedure was repeated again, and the final insoluble material was filtered using a G2 crucible and by washing with ethanol and hot water.

Hemicelluloses were determined by difference.

#### *2.3. Liquefaction*

In order to study the optimal conditions of liquefaction for the branches of *Cytisus scoparius* shrubs (CsB), different liquefaction reaction times, temperature and size of the samples were tested.

The liquefaction process was conducted in a double shirt reactor (600 mL) heated with oil (Reactor Parr LKT PED). The samples were introduced in the reactor with a mixture of glycerol and ethylene glycol 1:1, catalyzed with sulfuric acid (3%). Liquefied samples were dissolved in methanol and filtered in a G3 crucible.

The liquefaction yield was determined by the insoluble material retained in the crucible according to Equation (2).

$$\text{Liquidation yield} \left( \% \right) = \frac{\text{Insolvable residue}}{\text{Dried initial material}} \times 100\tag{2}$$

The effect of particle size was studied for five fractions, >35 mesh (>0.425 mm); 35–40 mesh (0.425–0.450 mm); 40–60 mesh (0.425–0.250 mm); 60–80 mesh (0.250–0.180 mm) and 80 mesh (<0.180 mm). The temperature ranged between 140 ◦C and 180 ◦C and liquefaction time from 15 to 60 min. Studies were made using different ratios of CsB:solvent, 1:5, 1:10 and 1:12.

#### **3. Results and Discussion**

#### *3.1. Chemical Composition*

Table 1 presents the chemical composition of CsB, where it can be observed that it is composed of 0.69% ashes, similar to the 0.78% obtained by González et al. with Broom from Ourense (north-west Spain) [34]. Ashes are essentially composed by potassium (0.694%) and calcium (0.046%) followed by sodium (0.042%), magnesium (0.030%) and phosphor (0.028%). This ash, given its composition rich in potassium and calcium, can be used in the glass industry to reduce the melting temperature of silica.

**Table 1.** Chemical composition of CsB.

a Corrected for the extractive content and ash. b Corrected for the extractive content, ash and alkaline extract.

Total extractives represented around 9.3%, most of which were soluble in ethanol (6.64%) and hot water (1.98%) and only 0.69% in dichloromethane. This means that extractives from Broom are most likely phenolic compounds and some small sugars that are obtained in ethanol and water extracts, respectively. These extractives are important since they proved to be good for the preparation of formulations for topical application to protect skin against oxidative damage [6,35]. Dichloromethane removes mostly non-polar extractives such as fatty acids, alkanes, waxes, terpenes and terpenoids, as stated before [36]. On the other hand, ethanol extractives are generally composed of lignans, flavonoid, stilbenes and mostly tannins (hydrolyzable and condensed). Some of these tannins have larger molecules and can only be removed by more aggressive extraction procedures such as 1% NaOH solutions. Results show that Broom has a high amount of such compounds. Klason lignin represents 14.57% of Broom, while cellulose *Kürscher and Höffer* represent around 36.1% and hemicelluloses 18.6%. The determination of the chemical composition will allow us to understand the possible uses of CsB better.

*Cytisus scoparius* chemical composition is somewhat different from the one presented by González et al. [34]. These authors reported similar ash (0.78%) and extractives content (9.13%) but a higher lignin percentage (26.6%); however, no alkaline extraction was made before lignin determination. Therefore, the existent polyphenols were most likely counted as lignin. In this study, the 20.8% alkaline extract has removed most of the polyphenols reducing the Klason lignin obtained. This extraction might also remove some other nontannin material, such as lignin [37] and possibly some hemicelluloses, as stated before [38].

On the other hand, the lignin content is not that far from the lignin content (16%) from Broom obtained from agricultural wastelands located in Zachodniopomorskie Voivodeship in Poland [39]. In the study by González et al. [34], cellulose was estimated by glucan to be around 40% and hemicelluloses by their sugar constituents to be around 19% which is similar to the results obtained here. Moreover, some chemical differences are expected since the origin of the plants is different. Results obtained for *Cytisus striatus*, generally called Portuguese Broom, are not that different, with 0.8% ash content, 4.7% ethanol toluene extractives, 22.4% lignin and 70% holocellulose [40]. to be around 40% and hemicelluloses by their sugar constituents to be around 19% which is similar to the results obtained here. Moreover, some chemical differences are expected since the origin of the plants is different. Results obtained for *Cytisus striatus*, generally called Portuguese Broom, are not that different, with 0.8% ash content, 4.7% ethanol toluene extractives, 22.4% lignin and 70% holocellulose [40]. *3.2. Liquefaction Optimization*

as lignin. In this study, the 20.8% alkaline extract has removed most of the polyphenols reducing the Klason lignin obtained. This extraction might also remove some other nontannin material, such as lignin [37] and possibly some hemicelluloses, as stated before [38]. On the other hand, the lignin content is not that far from the lignin content (16%) from Broom obtained from agricultural wastelands located in Zachodniopomorskie Voivodeship in Poland [39]. In the study by González et al. [34], cellulose was estimated by glucan

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#### *3.2. Liquefaction Optimization* Figure 1 presents the variation of the liquefaction yield with the size of particles. Results show that for the larger particles >35 mesh, the percentage of liquefaction was only

Figure 1 presents the variation of the liquefaction yield with the size of particles. Results show that for the larger particles >35 mesh, the percentage of liquefaction was only around 62.5% which can mean that the size of some of these particles was too big for them to be solubilized. On the other hand, for lower-size particles, the differences between the different sizes are small with 35–40 mesh, 40–60 mesh and <80 mesh (powder) with a very similar value ranging from 92.4 to 95.1%. In relation to 60–80 mesh particles, the percentage of liquefaction was slightly lower (80.9%), which can be due to the different chemical composition in this particle size has observed before [14,17,41]. The different chemical composition of each fraction is particularly important in heterogeneous materials such as in this case where there is a mixture of wood, bark and even flowers with very different chemical composition between each other. This result is extremely important as it allows industries to use larger particles (below 35 mesh), excluding the time-consuming process and complex transformation of *Cytisus scoparius* bushes to dust. around 62.5% which can mean that the size of some of these particles was too big for them to be solubilized. On the other hand, for lower-size particles, the differences between the different sizes are small with 35–40 mesh, 40–60 mesh and <80 mesh (powder) with a very similar value ranging from 92.4 to 95.1%. In relation to 60–80 mesh particles, the percentage of liquefaction was slightly lower (80.9%), which can be due to the different chemical composition in this particle size has observed before [14,17,41]. The different chemical composition of each fraction is particularly important in heterogeneous materials such as in this case where there is a mixture of wood, bark and even flowers with very different chemical composition between each other. This result is extremely important as it allows industries to use larger particles (below 35 mesh), excluding the time-consuming process and complex transformation of *Cytisus scoparius* bushes to dust.

**Figure 1.** Liquefaction yield for different particle size for the *Cytisus scoparius* branches (CsB) (con-**Figure 1.** Liquefaction yield for different particle size for the *Cytisus scoparius* branches (CsB) (constant parameters: 180 ◦C, time 60 min and ratio CsB:solvent of 1:10).

stant parameters: 180 °C, time 60 min and ratio CsB:solvent of 1:10). To perform an optimization of the CsB/solvent ratios, tests with different ones were performed using 1:5, 1:10, 1:12 for 60 min (min) at 180 °C. The results obtained are given To perform an optimization of the CsB/solvent ratios, tests with different ones were performed using 1:5, 1:10, 1:12 for 60 min (min) at 180 ◦C. The results obtained are given in Figure 2.

in Figure 2. The results show an increase in liquefaction yield, between 54.8%, 55.8% and 87.2% for a CsB/solvent ratio of 1:5, 1:10 and 1:12, respectively. In fact, this shows that using a higher amount of solvent leads to better liquefaction yields, as proven before [17]; however, it should be noted that more solvent corresponds to a higher cost. Thus, in the choice of solvent ratio, economic and environmental issues should be considered. It was decided to use the 1:10 ratio rather than the 1:5 ratio for the subsequent tests since, although here the difference is small, some earlier tests have shown that 1:5 was not enough in some conditions, and choosing this ratio could affect the study of the other parameters [17].

Figure 3.

**Liquefaction Yield (%)**

**50.0**

**60.0**

**70.0**

**80.0**

**90.0**

**100.0**

**10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 100.0**

**Liquefaction Yield (%)**

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**Figure 2.** Study of the ratio CsB:solvent for the samples of the branches (CsB) of *Cytisus scoparius* (constant parameters: 180 °C, time 60 min and size for the samples <80 mesh). **Figure 2.** Study of the ratio CsB:solvent for the samples of the branches (CsB) of *Cytisus scoparius* (constant parameters: 180 ◦C, time 60 min and size for the samples <80 mesh).Temperature optimization was performed by varying the temperature between 140 °C and 180 °C, keeping all other parameters constant. The results obtained are shown in

conditions, and choosing this ratio could affect the study of the other parameters [17].

The results show an increase in liquefaction yield, between 54.8%, 55.8% and 87.2% Temperature optimization was performed by varying the temperature between 140 ◦C and 180 ◦C, keeping all other parameters constant. The results obtained are shown in Figure 3. Figure 3.

**Figure 3.** Study of the temperature for the samples of the branches (CsB) of *Cytisus scoparius* (constant parameters: time 60 min, size for the samples <80 mesh and ratio CsB:solvent of 1:10). **Figure 3.** Study of the temperature for the samples of the branches (CsB) of *Cytisus scoparius* (constant parameters: time 60 min, size for the samples <80 mesh and ratio CsB:solvent of 1:10).

The liquefaction yield increased with the increase of temperature liquefaction, achieving a promising value of 95.1% for 180 °C. At lower temperatures, the liquefaction yield was only 65% and 73.5% for 140 °C and 160 °C, respectively. The high percentage of liquefaction for 180 °C is higher than that obtained for other materials in similar conditions, such as, for example, E*ucalyptus globulus* bark (61.6%) and branches (62.2%) [26]. Until 180 °C, no recondensation reactions were observed, or at least it was not significant, The liquefaction yield increased with the increase of temperature liquefaction, achieving a promising value of 95.1% for 180 ◦C. At lower temperatures, the liquefaction yield was only 65% and 73.5% for 140 ◦C and 160 ◦C, respectively. The high percentage of liquefaction for 180 ◦C is higher than that obtained for other materials in similar conditions, such as, for example, *Eucalyptus globulus* bark (61.6%) and branches (62.2%) [26]. Until 180 ◦C, no recondensation reactions were observed, or at least it was not significant, probably due to the use of a co-solvent system by the addition of a low-molecular-weight glycol (glycerol) and ethylene glycol, as mentioned before [15].

**130 140 150 160 170 180 190**

stant parameters: time 60 min, size for the samples <80 mesh and ratio CsB:solvent of 1:10).

**Figure 3.** Study of the temperature for the samples of the branches (CsB) of *Cytisus scoparius* (con-

achieving a promising value of 95.1% for 180 °C. At lower temperatures, the liquefaction yield was only 65% and 73.5% for 140 °C and 160 °C, respectively. The high percentage of liquefaction for 180 °C is higher than that obtained for other materials in similar conditions, such as, for example, E*ucalyptus globulus* bark (61.6%) and branches (62.2%) [26]. Until 180 °C, no recondensation reactions were observed, or at least it was not significant,

The liquefaction yield increased with the increase of temperature liquefaction,

The optimization of liquefaction time was performed by varying the time between 15 and 60 min, keeping all other parameters constant. The results obtained are presented in Figure 4. The optimization of liquefaction time was performed by varying the time between 15 and 60 min, keeping all other parameters constant. The results obtained are presented in Figure 4.

probably due to the use of a co-solvent system by the addition of a low-molecular-weight

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glycol (glycerol) and ethylene glycol, as mentioned before [15].

**Figure 4.** Study of liquefaction yield along liquefaction time for Broom branches for the fraction > 80 mesh (powder) at 180 °C with acid catalysis. **Figure 4.** Study of liquefaction yield along liquefaction time for Broom branches for the fraction > 80 mesh (powder) at 180 ◦C with acid catalysis.

Results show that it takes only 30 min to obtain a good liquefaction yield of 77.7% but also, that higher liquefaction can be obtained for 60 min (95.1%). The liquefaction yield was higher than the obtained for walnut shells (85%) before [42]. No decrease was observed with the increase in temperature, as reported, for instance, by Soares et al. [23] with cork liquefaction. These authors observed a decrease in higher temperatures which was Results show that it takes only 30 min to obtain a good liquefaction yield of 77.7% but also, that higher liquefaction can be obtained for 60 min (95.1%). The liquefaction yield was higher than the obtained for walnut shells (85%) before [42]. No decrease was observed with the increase in temperature, as reported, for instance, by Soares et al. [23] with cork liquefaction. These authors observed a decrease in higher temperatures which was attributed to polycondensation reactions between the liquefaction intermediates. Depending on the final product to be produced, a lower or higher liquefaction can be obtained.

attributed to polycondensation reactions between the liquefaction intermediates. Depending on the final product to be produced, a lower or higher liquefaction can be obtained. The high percentage of liquefaction (95%) shows that broom can be successfully liquefied bi polyalcohols with acid catalysis. The percentage of liquefaction is higher than the one obtained before for several other lignocellulosic materials such as rice straw, oilseed rape straw, wheat straw or corn stover [22] or orange peel wastes [43]. The low The high percentage of liquefaction (95%) shows that broom can be successfully liquefied bi polyalcohols with acid catalysis. The percentage of liquefaction is higher than the one obtained before for several other lignocellulosic materials such as rice straw, oilseed rape straw, wheat straw or corn stover [22] or orange peel wastes [43]. The low amount of residue allows using the obtained polyol without any separation between the solid residue and the liquefied material, which can be costly. Therefore, Broom has a nice potential to be used for the production of polyurethane foams, as was done before for several lignocellulosic materials, for instance, wood, barks or agricultural wastes [22,43–46].

#### amount of residue allows using the obtained polyol without any separation between the *3.3. FTIR of Liquefaction*

solid residue and the liquefied material, which can be costly. Therefore, Broom has a nice potential to be used for the production of polyurethane foams, as was done before for several lignocellulosic materials, for instance, wood, barks or agricultural wastes [22,43– 46]. *3.3. FTIR of Liquefaction*  Figure 5 presents the variation of the FTIR spectrum between the initial material and the liquefied polyol at 180 °C for 15 min, 30 min and 60 min. There are no major differences between the spectra of polyols produced with 15 min, 30 min or 60 min reactions. Big Figure 5 presents the variation of the FTIR spectrum between the initial material and the liquefied polyol at 180 ◦C for 15 min, 30 min and 60 min. There are no major differences between the spectra of polyols produced with 15 min, 30 min or 60 min reactions. Big differences are observed between the initial and the liquefied material. There is a clear increase in the hydroxyl peak and a shifting of the peak maximum from around 3350 cm−1 to around 3250 cm−1 . This is to be expected since the solvents used, glycerol and ethyleneglycol, are alcohols and, therefore, have several hydroxyl groups in their constitution. The shifting for lower wavenumbers can be due to the different functional groups present in liquefied material. Generally, alcohols absorb at higher wavenumbers (3600–3300 cm−1 ) than carboxylic acids (3300–2500 cm−1 ), therefore, this shifting to lower wavenumbers could be due to the increase in carboxylic acids. Nevertheless, generally, the

differences are observed between the initial and the liquefied material. There is a clear increase in the hydroxyl peak and a shifting of the peak maximum from around 3350 cm−1

tion. The shifting for lower wavenumbers can be due to the different functional groups present in liquefied material. Generally, alcohols absorb at higher wavenumbers (3600– 3300 cm−1) than carboxylic acids (3300–2500 cm−1), therefore, this shifting to lower wavenumbers could be due to the increase in carboxylic acids. Nevertheless, generally, the C=O C=O of carboxylic acids has a strong absorption at about 1725–1700 cm−1 , which is not seen in liquefied spectra. very different from those observed for sweet cherry seeds, which can be due to the significantly different chemical composition between them.

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liquefied spectra.

of carboxylic acids has a strong absorption at about 1725–1700 cm−1, which is not seen in

cm−1. Similar behavior has been observed before for liquefied cherry seeds [48].

The CH peaks are also very different in the polyol and in the initial material. These bands result from the overlapping of -CH2- (2935–2915 cm−1) and -CH3 (2970–2950 cm−1) stretching asymmetric vibrations and -CH2- (2865–2845 cm−1) and -CH3 (2880–2860 cm−1) stretching symmetric vibrations [47]. The original peaks are sharper, and there is an increase in the 2850 cm−1 peak in relation to 2930 cm−1 shifting the maximum to around 2860

The peak at 1730 cm−1, corresponding to non-conjugated C=O linkages, completely disappeared in the spectra of the liquefied material, and the 1650 cm−1 band was significantly reduced and narrowed. This might be due to the low amount of lignin in the initial material and to the lower resistance of Broom polysaccharides to hydrolysis. This is in line with the increase observed in this peak in the FTIR spectrum of the solid residue, especially after 60 min liquefaction. Similarly, the peak at 1510 cm−1 also disappears in the polyol spectra, and this peak has been associated with benzene ring stretching vibrations [47,49]. The 1230 cm−1 peak also decreases in the liquefied material. Although there is an apparent decrease in the 1030 cm−1 peak, this might be due to the high increase in the 3350 cm−1 band that proportionally decreases the remaining peaks. There is, however, a narrowing of the peak and the appearance of a more pronounced shoulder at 1100 cm−1. There is a new visible peak appearing at around 850 cm−1 which can be due to stretching vibrations in the pyranose ring [49]. The changes in FTIR spectra for the liquefied material are

**Figure 5.** FTIR spectra of the initial material and the liquefied polyol at 180 °C for 15 min, 30 min and 60 min at 180 °C with acid catalysis. **Figure 5.** FTIR spectra of the initial material and the liquefied polyol at 180 ◦C for 15 min, 30 min and 60 min at 180 ◦C with acid catalysis.

Figure 6 presents the variation of the FTIR spectrum between the initial material and the liquefied polyol for a 60 min reaction at 140 °C, 160 °C and 180 °C. Similar to the results presented in Figure 6, the main differences are observed between the initial and the liquefied material. Nevertheless, at 140 °C, there is a smaller increase in the 3350 cm−1 band and a much higher C-O-C peak at 1030 cm−1 in relation to the other temperatures. The CH peaks are also very different in the polyol and in the initial material. These bands result from the overlapping of -CH2- (2935–2915 cm−1 ) and -CH3 (2970–2950 cm−1 ) stretching asymmetric vibrations and -CH2- (2865–2845 cm−1 ) and -CH3 (2880–2860 cm−1 ) stretching symmetric vibrations [47]. The original peaks are sharper, and there is an increase in the 2850 cm−1 peak in relation to 2930 cm−1 shifting the maximum to around 2860 cm−1 . Similar behavior has been observed before for liquefied cherry seeds [48].

The peak at 1730 cm−1 , corresponding to non-conjugated C=O linkages, completely disappeared in the spectra of the liquefied material, and the 1650 cm−1 band was significantly reduced and narrowed. This might be due to the low amount of lignin in the initial material and to the lower resistance of Broom polysaccharides to hydrolysis. This is in line with the increase observed in this peak in the FTIR spectrum of the solid residue, especially after 60 min liquefaction. Similarly, the peak at 1510 cm−1 also disappears in the polyol spectra, and this peak has been associated with benzene ring stretching vibrations [47,49]. The 1230 cm−1 peak also decreases in the liquefied material. Although there is an apparent decrease in the 1030 cm−1 peak, this might be due to the high increase in the 3350 cm−1 band that proportionally decreases the remaining peaks. There is, however, a narrowing of the peak and the appearance of a more pronounced shoulder at 1100 cm−1 . There is a new visible peak appearing at around 850 cm−1 which can be due to stretching vibrations in the pyranose ring [49]. The changes in FTIR spectra for the liquefied material are very different from those observed for sweet cherry seeds, which can be due to the significantly different chemical composition between them.

Figure 6 presents the variation of the FTIR spectrum between the initial material and the liquefied polyol for a 60 min reaction at 140 ◦C, 160 ◦C and 180 ◦C. Similar to the results presented in Figure 6, the main differences are observed between the initial and the liquefied material. Nevertheless, at 140 ◦C, there is a smaller increase in the 3350 cm−1 band and a much higher C-O-C peak at 1030 cm−1 in relation to the other temperatures.

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init

**Figure 6.** FTIR spectra of the initial material and the liquefied polyol for a 60 min reaction at 140 °C, 160 °C and 180 °C with acid catalysis. **Figure 6.** FTIR spectra of the initial material and the liquefied polyol for a 60 min reaction at 140 ◦C, 160 ◦C and 180 ◦C with acid catalysis. **Figure 6.** FTIR spectra of the initial material and the liquefied polyol for a 60 min reaction at 140 °C, 160 °C and 180 °C with acid catalysis.

Figure 7 presents the FTIR spectra of the initial material and of the solid residue obtained by liquefaction at 180 °C for 15 min, 30 min and 60 min reaction time. The solid residue spectrum changes rapidly from the initial material and along the reaction time. There is a slight narrowing of the 3350 cm−1 band in the initial of the liquefaction and a decrease for 60 min reaction time. In relation to the CH peaks, there is a decrease of the 2930 cm−1 peak followed by an increase for longer reaction times. The same seems to happen to the 1730 cm−1 peak and somewhat to the 1650 cm−1 band. These changes might be due to an initial cleavage of acetyl or acetoxy groups in hemicelluloses. The fingertip region is much less defined in the solid residue, and there seems to be a decrease at the 1226 cm−1 peak. The C-O-C peak also seems to increase and decrease later. Figure 7 presents the FTIR spectra of the initial material and of the solid residue obtained by liquefaction at 180 ◦C for 15 min, 30 min and 60 min reaction time. The solid residue spectrum changes rapidly from the initial material and along the reaction time. There is a slight narrowing of the 3350 cm−1 band in the initial of the liquefaction and a decrease for 60 min reaction time. In relation to the CH peaks, there is a decrease of the 2930 cm−1 peak followed by an increase for longer reaction times. The same seems to happen to the 1730 cm−1 peak and somewhat to the 1650 cm−1 band. These changes might be due to an initial cleavage of acetyl or acetoxy groups in hemicelluloses. The fingertip region is much less defined in the solid residue, and there seems to be a decrease at the 1226 cm−1 peak. The C-O-C peak also seems to increase and decrease later. Figure 7 presents the FTIR spectra of the initial material and of the solid residue obtained by liquefaction at 180 °C for 15 min, 30 min and 60 min reaction time. The solid residue spectrum changes rapidly from the initial material and along the reaction time. There is a slight narrowing of the 3350 cm−1 band in the initial of the liquefaction and a decrease for 60 min reaction time. In relation to the CH peaks, there is a decrease of the 2930 cm−1 peak followed by an increase for longer reaction times. The same seems to happen to the 1730 cm−1 peak and somewhat to the 1650 cm−1 band. These changes might be due to an initial cleavage of acetyl or acetoxy groups in hemicelluloses. The fingertip region is much less defined in the solid residue, and there seems to be a decrease at the 1226 cm−1 peak. The C-O-C peak also seems to increase and decrease later.

°C for 15 min, 30 min and 60 min reaction time with acid catalysis.

°C for 15 min, 30 min and 60 min reaction time with acid catalysis.

The changes observed in the solid residue along the liquefaction time are similar to those presented in Figure 8 with the increase in liquefaction temperature. The changes observed in the solid residue along the liquefaction time are similar to those presented in Figure 8 with the increase in liquefaction temperature.

**Figure 8.** FTIR spectra of the initial material and of the solid residue obtained by liquefaction for 60 min at temperatures 140 °C, 160 °C and 180 °C with acid catalysis. **Figure 8.** FTIR spectra of the initial material and of the solid residue obtained by liquefaction for 60 min at temperatures 140 ◦C, 160 ◦C and 180 ◦C with acid catalysis.

FTIR analysis shows that it is not only one of the macromolecular compounds that is being liquefied but rather that all the chemical compounds are affected by polyalcohol liquefaction with acid catalysis. FTIR analysis shows that it is not only one of the macromolecular compounds that is being liquefied but rather that all the chemical compounds are affected by polyalcohol liquefaction with acid catalysis.

#### **4. Conclusions**

**4. Conclusions**  Results have shown that in relation to macromolecular compounds, Broom is mainly composed of cellulose, followed by hemicelluloses and lignin. Alkaline extract represented more than 20% and is probably composed of tannins. Extractives were more than 9%, with ethanol soluble representing more than half, followed by water soluble and dichloromethane extractives. These phenolic compounds can be retrieved before liquefaction in a biorefinery approach. Ashes were around 0.69%. No significative differences were found for the different fractions, although the 40–60 mesh fraction presented the best results. A higher amount of solvent improved the liquefaction percentage. The same was observed for higher temperatures and the time of liquefaction. At the ideal conditions, a high percentage of liquefaction (95%) could be achieved, better than most lignocellulosic materials. These conditions were 180 °C, 60 min for the 40–60 mesh fraction. The results have proven that Broom can be a valuable material that, once liquefied, can be later used for the manufacture of goods without any further separation Results have shown that in relation to macromolecular compounds, Broom is mainly composed of cellulose, followed by hemicelluloses and lignin. Alkaline extract represented more than 20% and is probably composed of tannins. Extractives were more than 9%, with ethanol soluble representing more than half, followed by water soluble and dichloromethane extractives. These phenolic compounds can be retrieved before liquefaction in a biorefinery approach. Ashes were around 0.69%. No significative differences were found for the different fractions, although the 40–60 mesh fraction presented the best results. A higher amount of solvent improved the liquefaction percentage. The same was observed for higher temperatures and the time of liquefaction. At the ideal conditions, a high percentage of liquefaction (95%) could be achieved, better than most lignocellulosic materials. These conditions were 180 ◦C, 60 min for the 40–60 mesh fraction. The results have proven that Broom can be a valuable material that, once liquefied, can be later used for the manufacture of goods without any further separation to substitute petroleum-based products such as, for instance, polyurethane foams.

**Author Contributions:** Conceptualization, L.C.-L. and B.E.; methodology, L.C.-L., Y.D. and B.E.; formal analysis, L.C.-L. and Y.D.; investigation, L.C.-L., Y.D., D.A. and B.E.; resources, L.C.-L., Y.D., I.D., J.F., A.F. and B.E.; writing—original draft preparation, Y.D.; writing—review and editing, L.C.- L. and B.E.; supervision, L.C.-L. All authors have read and agreed to the published version of the **Author Contributions:** Conceptualization, L.C.-L. and B.E.; methodology, L.C.-L., Y.D. and B.E.; formal analysis, L.C.-L. and Y.D.; investigation, L.C.-L., Y.D., D.A. and B.E.; resources, L.C.-L., Y.D., I.D., J.F., A.F. and B.E.; writing—original draft preparation, Y.D.; writing—review and editing, L.C.-L. and B.E.; supervision, L.C.-L. All authors have read and agreed to the published version of the manuscript.

to substitute petroleum-based products such as, for instance, polyurethane foams.

manuscript. **Funding:** This work is funded by National Funds through the FCT—Foundation for Science and Technology. I.P. within the scope of the project Ref UIDB/00681/2020 (CERNAS) and Ref **Funding:** This work is funded by National Funds through the FCT—Foundation for Science and Technology. I.P. within the scope of the project Ref UIDB/00681/2020 (CERNAS) and Ref UIDB/05507/ 2020 (CI&DEI).

UIDB/05507/2020 (CI&DEI). **Acknowledgments:** We would like to thank the CERNAS and CI&DEI Researchs Centres and the Polytechnic Institutes of Viseu for their support and the PROJ/IPV/ID&I/021 "Valorização de **Acknowledgments:** We would like to thank the CERNAS and CI&DEI Researchs Centres and the Polytechnic Institutes of Viseu for their support and the PROJ/IPV/ID&I/021 "Valorização de resíduos: potencial de aproveitamento do caroço de cereja (VALCER)" by Yulia's Research Grant.

resíduos: potencial de aproveitamento do caroço de cereja (VALCER)" by Yulia's Research Grant.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

## **References**


**Author details**

Mehmet Faruk Kose1 \* and Emine Karabuk2

1 Department of Gynecologic and Oncology, School of Medicine, Acibadem Mehmet Ali Aydinlar University, Turkey

2 Department of Obstetrics and Gynecology, School of Medicine, Acibadem Mehmet Ali Aydinlar University, Turkey

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


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