*1.2. Water Quality and Coral Reefs along the North Coast of Timor-Leste*

Pollution arising from disturbed coastal regions and watersheds poses a serious threat to coral reefs globally. This type of pollution includes a wide range of compounds such as agrochemicals (pesticides), inorganic nutrients (nitrate, ammonia, and phosphate), soils and sediments, and fossil fuel residues that flow from disturbed landscapes. Many of these compounds negatively affect coral physiology by reducing calcification rates, fecundity, fertilization success, and larval development [33]. This can degrade reef communities reducing coral cover, community composition, diversity, and structural complexity [34,35]. High levels of marine pollution can increase the prevalence and severity of disease and susceptibility to bleaching [36–40]. Dissolved inorganic nitrogen (DIN = ammonium + nitrate + nitrite) measurements on reefs are generally <1.5 μM (individual species ammonium, nitrate, nitrite < 1 μM) with even lower phosphate concentrations (<0.3 μM; Table S2) [37,41–47]. A greater prevalence of disease has been associated with elevated concentrations of DIN from anthropogenic sources (fertilizer, sewage pollution, etc.) and phosphate ranging from 3.6 μM to 25.6 μM and 0.3 μM to 0.4 μM, respectively [41,42,45–47].

The isotopic signature of nutrients such as nitrogen can often serve as a tracer for different sources of coastal pollution, with different forms of input having different impacts

(sewage can increase pathogen concentrations) and solutions [32,48–57]. Stable isotope analyses of nitrogen stored in macroalgae can provide a nutrient signal integrated over time versus water sampling, which is highly variable over space and time [58]. Generally, δ15N signatures in algae associated with urban wastewater are >10‰ [59–62]. Natural and synthetic fertilizers display a large range from −4‰ to +4‰ of δ15N values while nitrogen fixation typically has a negative δ15N signature between −2 and 0‰ [63]. Upwelling can have variable δ15N values ranging from 5 to12‰ [50,64–70]. Both fertilizer use and waste infrastructure are expected to be developed as described in the national strategic development plan [19].


**13. Recommendations**

Drawing from the empirical data gathered from the field study, the researchers recommended as that:

*A Comparative Analysis of Undergraduates' Preference between Traditional Television and OTT… DOI: http://dx.doi.org/10.5772/intechopen.113308*


*Maintenance Decision Method Based on Risk Level DOI: http://dx.doi.org/10.5772/intechopen.91913*

#### **Table 1.**

brought about in their maintenance work [1]. At present, based on the different attention focuses in each industry and the different model and method choices in the maintenance and management process, many research results are related to the maintenance decision method. Bertolini and Bevilacqua [2] proposed a new maintenance decision method to adopt a modified FEMCA analysis and a type of Monte Carlo simulation (MCS) approach based on different important levels of the power plant equipment. Bertolini and Bevilacqua presented a new maintenance decision technique to determine the better maintenance strategies for the critical centrifugal pumps in an oil refinery [3]. A maintenance decision method of a multi-criteria classification of equipment was proposed by Gómez de León Hijes and Cartagena by the analytic hierarchy process (AHP), and oil pipeline projects were effectively evaluated by Dey with a multiple attribute decision-making technique [4, 5]. Chang et al. applied a new maintenance decision model to estimate the production availability in offshore installations [6]. In the study above, some mathematical models, including AHP and MCS, are often used for making maintenance decisions. However, through research and investigation, very few applications of both AHP and MCS exist for making maintenance decisions of the mechanical equipment based on their different risk levels. Moreover, there are some differences between the mechanical equipment in the petrochemical industry and the ones in other industries, such as types and distribution of the failure, the methods and costs of the maintenance, and requirements for reliability and safety, due to the factors of harsh construction environments, complicated working conditions, and extremely high

Thus, these existing maintenance decision models and the maintenance strategies applied to the equipment in other industries are not directly suitable for the mechanical equipment in the petrochemical industry [8]. Therefore, it is necessary to study the maintenance decision method belonging to the mechanical equipment in the petrochemical production process by focusing on the features of its high risks and hazards [9]. A new framework is put forward for making maintenance decisions based on the different risk levels of the mechanical equipment. Finally, through the framework of maintenance decision making, a more reasonable and more effective maintenance strategy can be devised for the mechanical equipment

The remainder of this chapter is organized as follows. In Section 2, the influence factors of the risk level of the mechanical equipment are defined, and their scoring criteria are formulated. In Section 3, an evaluation model for the risk level of the mechanical equipment is established using AHP, and then, the MCS approach is applied to reduce the subjective influences in the scoring process. Then, three MDMETs for the mechanical equipment are obtained based on their categories of different risk levels in Section 4. Finally, Section 5 provides some discussion and

to guarantee the reliability and security of the production operation.

**2. Maintenance decision method based on risk level**

**2.1 Definition of evaluation indexes and scoring criteria of risk level**

Through the FMECA of the mechanical equipment in the petrochemical industry, from the four aspects of reliability, economics, monitorability, and maintainability, 10 influencing factors directly related to its risk level were analyzed, as

In order to ensure that the evaluation of the risk level of machinery and equipment is not too complicated, and that the accuracy of evaluation is balanced, and

safety requirements in the production process [7].

*Operations Management - Emerging Trend in the Digital Era*

conclusions.

shown in **Table 1** [10].

**332**

*Influencing factors of risk level about the mechanical equipment.*

#### **Table 2.** *Scoring criteria of PS.*

the degree of influence of each factor is more effectively quantified. Therefore, by experts, professional maintenance personnel and field operators through the review pointed out that the risk level of influencing factors according to the situation divided into 3–5 levels, using a 10-point system for scoring. The scoring standards for the 10 influencing factors related to the risk level of mechanical equipment are as follows [11].


**2.6 Simulations and discussions: A comparative study**

The ratings and parameters of the induction machine, used in the simulation study, are listed in **Tables 2** and **3** respectively.

#### **Figure 2.**

**2.5 Concept of DTC-SVM with hysteresis controllers based position control**

*cϕ* **+1 1**

*V*1 (101)

*V*2 (100)

*V*3 (110)

*V*4 (010)

*V*5 (011)

*V*6 (001)

*Look-up table with zero-voltage vectors substituted by active ones.*

*cr* **+1 0 1 +1 0 1**

*V*6 (001)

*V*1 (101)

*V*2 (100)

*V*3 (110)

*V*4 (010)

*V*5 (011)

*V*3 (110)

*V*4 (010)

*V*5 (011)

*V*6 (001)

*V*1 (101)

*V*2 (100)

*V*4 (010)

*V*5 (011)

*V*6 (001)

*V*1 (101)

*V*2 (100)

*V*3 (110)

*V*5 (011)

*V*6 (001)

*V*1 (101)

*V*2 (100)

*V*3 (110)

*V*4 (010)

lers applied to the position regulation of an induction motor drive is shown in **Figure 2**. It has the same layout as the one of the basic DTC strategy proposed in section II, except that the SVM bloc is added to the control system that ensures an

imposed switching frequency [7–12].

**Figure 1.**

S1 *V*2

S2 *V*3

S4 *V*4

S4 *V*5

S5 *V*6

S6 *V*1

**Table 1.**

**42**

(100)

(110)

(010)

(011)

(001)

(101)

*IM position regulation based on basic DTC strategy.*

*Direct Torque Control Strategies of Electrical Machines*

The implementation scheme of the DTC-SVM strategy with hysteresis control-

*Induction motor position regulation based on the DTC-SVM strategy.*

**Table 2.** *Induction machine ratings.*

#### **Table 3.**

*Induction machine parameters.*

**Figure 3.**

*Induction motor position regulation under the basic Takahashi DTC strategy, (a): Rotor position θ and its reference, (b): Speed* Ω*m, (c): Electromagnetic torque Tem, (d): Stator flux* Φ*s.*

**Figures 3**–**5** show the induction motor dynamic following the application of a dual-step reference position under the basic *Takahashi* DTC strategy, the modified *Takahashi* one, and the DTC-SVM strategy with a controlled commutation frequency, respectively. In order to highlight performances gained by the DTC-SVM scheme, resulting features are compared to the obtained ones following the implementation of the basic DTC strategy. The analysis of these results leads to the following remarks:

**Figure 5.**

**45**

**Figure 4.**

*Induction motor position regulation under the DTC-SVM strategy with a constant commutation frequency of 6.5 kHz, (a) rotor position θ, (b): Speed* Ω*m,: (b): Electromagnetic torque Tem, (d): Stator flux* Φ*s.*

*Induction motor position regulation under the modified Takahashi DTC strategy, (a): Rotor position θ and its*

*DTC-SVM Approaches of an Induction Motor Dedicated to Position Control Applications*

*DOI: http://dx.doi.org/10.5772/intechopen.94436*

*reference, (b): Speed* Ω*m, (c): Electromagnetic torque Tem, (d): Stator flux* Φ*s.*

*DTC-SVM Approaches of an Induction Motor Dedicated to Position Control Applications DOI: http://dx.doi.org/10.5772/intechopen.94436*

**Figure 4.**

**Figures 3**–**5** show the induction motor dynamic following the application of a dual-step reference position under the basic *Takahashi* DTC strategy, the modified *Takahashi* one, and the DTC-SVM strategy with a controlled commutation frequency, respectively. In order to highlight performances gained by the DTC-SVM scheme, resulting features are compared to the obtained ones following the

*Induction motor position regulation under the basic Takahashi DTC strategy, (a): Rotor position θ and its*

*reference, (b): Speed* Ω*m, (c): Electromagnetic torque Tem, (d): Stator flux* Φ*s.*

*rs* ¼ 0*:*29Ω *rr* ¼ 0*:*38Ω *M* ¼ 47*:*3mH *Ls* ¼ *Lr* ¼ 50mH *Np* ¼ 2 *J* ¼ 0*:*5Kg*:*m2

implementation of the basic DTC strategy. The analysis of these results leads to the

• **Figures 3a**–**5a** show that the three DTC strategies exhibit almost the same

• Performances of the flux loop of the basic *Takahashi* DTC strategy is affected by the demagnetized phenomenon (**Figure 3d**). In fact, the analysis of the *Takahashi* strategy highlights low performances at low speed operations. Under such conditions, and for steady state operations, the motor turns to be

• In order to overcome the demagnetization problem caused by zero-voltage vectors included in the look-up table of the basic DTC strategy, these have

following remarks:

**Figure 3.**

**Table 3.**

*Induction machine parameters.*

*Direct Torque Control Strategies of Electrical Machines*

demagnetized.

**44**

position and speed dynamics,

*Induction motor position regulation under the modified Takahashi DTC strategy, (a): Rotor position θ and its reference, (b): Speed* Ω*m, (c): Electromagnetic torque Tem, (d): Stator flux* Φ*s.*

**Figure 5.**

*Induction motor position regulation under the DTC-SVM strategy with a constant commutation frequency of 6.5 kHz, (a) rotor position θ, (b): Speed* Ω*m,: (b): Electromagnetic torque Tem, (d): Stator flux* Φ*s.*

been substituted by active vectors. Obtained results are illustrated in **Figure 4**. Referring to **Figure 4d**, one can notice that the demagnetization problem has been removed, while performances of the motor, for high speeds, are not affected. However, the torque ripple amplitudes rise considerably (**Figure 4c**) with respect to the one yielded by the *Takahashi* DTC strategy, which represents a severe drawback.

done considering the three DTC strategies. Obtained results are shown in **Figure 6**. One can notice, easily, that the DTC-SVM strategy with hysteresis regulators and with an imposed commutation frequency yields to the smoothest

*DTC-SVM Approaches of an Induction Motor Dedicated to Position Control Applications*

**3. Concept of PI DTC-SVM based position control**

**3.1 Computing of flux reference coordinates**

ð Þ *α*, *β* , coordinates of the reference stator flux *ϕ*∗

**3.2 Computing of voltage reference coordinates**

determined by the following equations:

inverter switches ð Þ *Sa*, *Sb*, *Sc* .

**3.3 Position control loop**

**Figure 8.**

**47**

*Position control loop.*

The coordinates of references of voltage vectors *v* ∗

polar coordinates according to the following expressions:

*ϕ*∗ *αs* ¼ ∣Φ∗

8 < :

*V* ∗ *αs* ¼ *ϕ*∗

8 >>>><

>>>>:

*V* ∗ *βs* ¼ *ϕ*∗

*ϕ*∗ *βs* ¼ ∣Φ∗

The slip angular reference speed *ω*∗

*DOI: http://dx.doi.org/10.5772/intechopen.94436*

Finally, we have involved in the assessment of the average commutation frequencies of both basic and modified *Takahashi* DTC strategies. Obtained results have been showing in **Figure 7**. It is to be noted that the basic DTC strategy and the DTC-SVM with an imposed commutation frequency ð Þ *Fc* ¼ 6*:*25*kHz* strategy offer lower commutation frequencies than the modified *Takahashi* DTC strategy.

be used to calculate the argument of the stator flux reference. In the reference frame

*s* ∣ cos *θ* ∗ *s*

*s* ∣sin *θ* ∗ *s*

*αs* � *ϕαs Te*

*βs* � *ϕβs Te*

Finally, they are introduced to the SVM block, which uses them to control the

The objective is the design of a suitable controller as described by **Figure 8**.

þ *Rsiαs*

þ *Rsiβs*

*r* , which is the output of the PI controller, will

*βs* are calculated from the

*βs* in ð Þ *α*, *β* frame are

(5)

(6)

*αs* and *ϕ*∗

*αs* and *v* ∗

circular locus.

• **Figure 5** shows that the DTC-SVM strategy exhibits high dynamical performances. In fact, this approach presents a low torque ripple amplitude (**Figure 5c**). Moreover, it completely eliminates the demagnetization phenomenon (**Figure 5d**).

Further investigation of the stator flux has been achieved through the representation of the stator flux vector extremity locus in the ð Þ *α*, *β* plane. This has been

#### **Figure 6.**

*Locus of the extremities of* Φ*s, with (a) basic Takahashi DTC strategy, (b) modified Takahashi DTC strategy and (c) DTC-SVM strategy with a constant commutation frequency.*

**Figure 7.**

*Average commutation frequency of the inverter power switches, (a) basic Takahashi DTC strategy, (b) modified Takahashi DTC strategy.*

*DTC-SVM Approaches of an Induction Motor Dedicated to Position Control Applications DOI: http://dx.doi.org/10.5772/intechopen.94436*

done considering the three DTC strategies. Obtained results are shown in **Figure 6**. One can notice, easily, that the DTC-SVM strategy with hysteresis regulators and with an imposed commutation frequency yields to the smoothest circular locus.

Finally, we have involved in the assessment of the average commutation frequencies of both basic and modified *Takahashi* DTC strategies. Obtained results have been showing in **Figure 7**. It is to be noted that the basic DTC strategy and the DTC-SVM with an imposed commutation frequency ð Þ *Fc* ¼ 6*:*25*kHz* strategy offer lower commutation frequencies than the modified *Takahashi* DTC strategy.


**1. Chronic Kidney Disease**

Chronic kidney disease (CKD) a ffects an increasing number of patients worldwide and is associated with dramatically increased morbidity and mortality [1,2]. Recent data suggest that CKD currently affects more than 10% of the population in the developed world [3,4].

Diabetes mellitus and high blood pressure are among the most prevalent risk factors for the development of CKD and are responsible for the majority of cases. Other conditions that a ffect the kidneys are glomerulonephritis, the third most common type of kidney disease, inherited diseases, such as polycystic kidney disease, and loss of renal tissue due to infections, malformations or urinary tract obstruction. Repeated episodes of acute kidney injury and certain therapeutics, such as non-steroidal anti-inflammatory drugs (NSAIDs) can also contribute to CKD [2].

In end-stage renal failure, dialysis and subsequent kidney transplantation are the only available treatment options apart from palliative care. However, not all patients qualify for kidney transplantation and transplant waiting times are often long. Thus, patients usually undergo many years of dialysis treatment. Longstanding uremia in turn promotes cardiovascular disease. Consequently, the leading causes of death in dialysis patients are sudden cardiac death and recurrent heart failure due to cardiac and vascular remodeling [5].


**Magda Sibley**

Sheffield School of Architecture, The University of Sheffield, Arts Tower, Western bank, Sheffield S10 2TN, UK<EMAIL_ADDRESS>or<EMAIL_ADDRESS>Tel.: +44-7930-988-8193

Received: 11 August 2018; Accepted: 28 October 2018; Published: 31 October 2018

**Abstract:** This paper provides the first study of vernacular daylighting provision in Moroccan heritage public bathhouses in order to rehabilitate it for experiential authenticity, energy saving and improved users' well-being. The analysis of a representative sample of 13 still working hammams reveals recurrent patterns of oculi numbers and configurations. These consist of one to three rows of eight circular roof openings (oculi) of 18 to 20 cm diameter, arranged along the roof vault of each bathing space. The ratio of total roof openings' area to internal floor area rarely exceeds 2%. Synchronised measurements of horizontal illuminance on the roof and inside the bathing spaces in a case study hammam were conducted in July and August 2016, after rehabilitating all roof oculi. Recorded levels indicated that maximum horizontal illuminance never exceeds 60 lx. The calculation and plotting of daylight factor based on real data reveal levels under 2% and a sudden decline in the hot room early afternoon due to steam accumulation. The paper provides the first benchmark of vernacular daylight rehabilitation in Moroccan heritage hammams and the illuminance it affords. It introduces an innovative combination of historical, architectural and building science methodologies that can be extended to other heritage building types.

**Keywords:** hammam; oculi; vernacular roof lighting; energy saving; well-being; daylighting rehabilitation; authenticity; horizontal illuminance


**Author details**

Sehar Zulkifal, Shumaila Sarwar1 , Madiha Saddique, Khalida Yaqoob, Arshia Muneer, Aisha Fatima, Ayesha Kabir, Muhammad Asad Mangat, Laiba Mateen, Zeeshan Javed and Maleeha Manzoor\* Faculty of Life Sciences, Department of Zoology, Government College University, Faisalabad, Pakistan

\*Address all correspondence to<EMAIL_ADDRESS>
© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

*Anemia during Pregnancy and Its Prevalence DOI: http://dx.doi.org/10.5772/intechopen.99521*


**2.27 High yielding**

These mutants showed superior yield attributes such as length and number of pods, number of seeds, 1000 seed weight and yield per plant as compared to control (Plate- 4). Auti (2005) stated that some unknown mechanism must be inducing the expression of yield controlling genes, which are responsible to increase the yield. Same may be the reason for getting high yielding mutants in horsegram. These mutants can break the constrains of low yield of horsegram, in rainfed agriculture.


*Edited by Riadh Marzouki*

Alkaline elements are present in large quantities and in different forms in the Earth's layers. They are widely used in the manufacture of materials showing interesting physical properties that can be applied in several fields, including catalysis, biology, energy, and others. This book describes different methods of synthesis and treatment of certain alkaline materials and their applications in different fields. It discusses alkaline chemistry in catalysis, biology, polymers and composites, and crystallography.

ISBN 978-1-83969-126-3

Alkaline Chemistry and Applications

Published in London, UK © 2022 IntechOpen © SimoneN / iStock


**About the Editor**

**Antonio Granero-Gallegos**, Ph.D., Associate Professor at the University of Almeria (Spain). He is a teacher of the Faculty of Educational Sciences and is also presently the coordinator of Degree in Sciences of Physical Activity and Sports and secretary of Health Research Center. He has 24 years of teaching experience at different educational levels and has researched various topics for 17 years, mainly about motivational variables related to teaching and learning processes in physical education and sport, physical activities in the natural environment, and body image. To date, he has published more than 120 papers in scientific journals indexed in the Web Of Science (WOS). h-index: 15 (WOS).

International Journal of *Environmental Research and Public Health*