**Abstract**

Modern ester based synthetic lubricants have been used in various formulations with anti-oxidants, phosphorus based anti-wear additives and other additives for many years. The physical and chemical properties of both the basestock and additives are known to change through use. Basestocks are normally thought to degrade through various mechanisms, while additive can either degrade or are used as they react when they complete the function that they are added for. In this chapter, the composition of modern turbine engine lubricants and the mechanisms by which the lubricants degrade over time will be examined. Potential changes in bearing materials being evaluated for future engines and the effects of possible new ionic liquids based additives will be will be discussed as they relate to currently used additives. Also included will be a discussion of effects of degradation on the lubricant properties, how the changes affect turbine engines and how the changes can impact human health. These new materials introduce a number of new possible degradation schemes that must be evaluated before the materials enter wide-spread use.

**Keywords:** lubrication, additives, oxidation, hydrolysis, decomposition, nanoparticles, phosphates, toxicity


*Edited by Kamal Shah*

This book provides a broad overview of recent developments in polynomials and their applications. It includes eight chapters that address such topics as characteristic functions of polynomials, permutations, Gončarov polynomials, irreducible factors, polynomial regression algorithms, and the use of polynomials in fractional calculus, and much more.

ISBN 978-1-83969-758-6

Recent Advances in Polynomials

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


**8. Breakthrough pain**

Breakthrough pain is a common problem in patients with cancer, being associated with significant morbidity. Currently, there is no universally accepted definition of ''breakthrough pain". Portenoy et al. have defined breakthrough pain as ''a transitory exacerbation of pain experienced by the patient who has relatively stable and adequately controlled baseline (background) pain" (Portenoy et al., 2004).

Breakthrough pain is usually classified into one of two categories:

Breakthrough pain is associated with poor overall pain control (Bruera et al., 1995) as well as decreased patient satisfaction with overall pain management (Zeppetella et al., 2000). In addition, breakthrough pain may result in a number of physical (e.g., immobility), psycho‐ logical (e.g., insomnia, anxiety, depression) and social (e.g., unemployment, social isolation) complications (Skinner et al., 2006). Indeed, the presence of breakthrough pain may have a significant impact on the quality of life (Skinner et al., 2006).[68]

## **9. Pain assessment**

Dysregulation of cortisol release results in peripheral vasoconstriction and limbs muscles catabolism. The inadequate cortisol regulation and the consequent loss of muscle mass can as well affect the amount of adipose tissue, leading to a relative increase of the latter. Chronic pain often predisposes to a complex series of physiological and psychosocial changes, which are an integral part of the chronic pain issue, being added to the existing burdens occurring to

> Multifocal bone pain, vertebral pain syndrome in epidural spinal cord compression, pain syndrome related to pelvis and hip, base of skull

Headache and facial pain, ear and eye pain, pleural pain, muscle cramps

syndrome, malignant perineal pain, ureteric obstruction

enteritis, lymphedema pain, osteoradionecrosis

Breakthrough pain is a common problem in patients with cancer, being associated with significant morbidity. Currently, there is no universally accepted definition of ''breakthrough pain". Portenoy et al. have defined breakthrough pain as ''a transitory exacerbation of pain experienced by the patient who has relatively stable and adequately controlled baseline

**1.** Spontaneous pain (''idiopathic pain") – the episodes are not related to any identifiable

**2.** Incident pain (''precipitated pain") – the episodes are related to an identifiable precipitant

factor. Incident pain is usually sub-classified into one of three categories:

Neuropathic pain due to malignancy Radiculopathies, mononeuropathies, plexopathies, neuralgias, peripheral

neuropathy

Breakthrough pain is usually classified into one of two categories:

Hepatic distention syndrome, chronic bowel obstruction, midline retroperitoneal

Peripheral neuropathy, chronic post-surgical pain (eg.mastectomy, thoracotomy, neck dissection, pelvic surgeries), phantom limb pain, chronic radiation myelopathy, chronic radiation plexopathy, chronic radiation proctitis and

those who suffer.  Chronic pain syndrome

**8. Breakthrough pain**

precipitant factors.

(background) pain" (Portenoy et al., 2004).

Nociceptive somatic pain due to soft

bone metastases

tissue involvement

malignancy

**7. Chronic pain syndromes**

**Causes Disorders**

Clinical practice guidelines developed by the National Comprehensive Cancer Network (NCCN) [69] and American Pain Society (APS) emphasize the essential need of a comprehen‐ sive pain assessment. [70]

A careful evaluation of pain should include history, pain description (in particular, establish‐ ing whether it worsens during the sleep), precipitating and alleviating factors, functional impairment, psychological associated factors, psychosocial history as well as patient's beliefs, physical examination, and a general knowledge of the different features of cancer-induced and nonmalignant pain; such evaluation will allow a comprehensive assessment of pain. Con‐ versely, an inadequate measurement and assessment of pain poses a significant obstacle to any effective pain management strategy.

Patient interview:

**Figure 4.** Pain assessment: Interview

An adequate pain assessment requires a thorough pain anamnesis as well as physical exami‐ nation prior to any radiographic study or physiological testing. Failing to collect a compre‐ hensive anamnesis and performing a correct physical examination will result in frequent mistakes, as correspondence between pain severity, as reported by the patient, and presence of underlying pathology, as revealed by imaging studies, is often poor. Location, radiation, quality, intensity and temporal pattern of pain should be ascertained along with provocative and palliative factors associated with pain; afterwards, the physician should map the source of pain and investigate any clues to a possible cause; finally, the following pain features should be identified:

Physical examination should be focused on the area of pain without overlooking areas of referred pain (such as the right shoulder in case of hepatic metastases).

Physical examination is followed by specific maneuvers in order to provoke or improve pain.

For instance, pain due to bone metastases may be provoked through local palpation and manipulation. Spinal cord compression resulting from epidural tumor extension represents a known challenge. Accordingly, a comprehensive neurologic examination, coupled with manual muscle testing, percussion of point of tenderness, evaluation of joint mobility, and inspection of muscle symmetry are crucial steps of any physical examination.

The assessment of psychiatric and psychosocial co-morbidities is crucial to address factors that may adversely affect pain perception and worsen patient's distress. Radiographic studies should be guided by the anamnesis and the physical examination, as well as stage of disease, patient performance status, therapeutic options, and care endpoints. When dealing with terminally ill patients, or when little would be gained by radiographic procedures, palliative measures should be implemented without putting the patient through painful, unnecessary testing. Whenever appropriate, pain treatment should be started as early as possible so that patients may be comfortable and able to complete the diagnostic procedure. Plain radiographs of painful areas may be of value.

Magnetic resonance imaging (MRI) of the spine and brain and computed tomography (CT) scanning of the chest and abdomen often provide the greatest amount of information. In case of pericardial effusions or biliary or urinary tract obstruction, ultrasonography may be easily accomplished with a portable device, thus avoiding radiation exposure. Electrophysiologic studies may be useful to distinguish mononeuropathies and entrapment neuropathies from plexopathies, as well as ulnar and peroneal entrapment syndromes from brachial and lumbar plexopathies, respectively. Conduction velocities, specific latencies, amplitudes, duration, and configurations of sensory and motor evoked potentials are the keys to identify and locate the neural pathology. Importantly, it should be remembered that results of electrophysiologic studies may be normal even with significantly damaged non-myelinated fibers.

The ability to measure pain implementing valid and standardized approaches has improved in the last years, increasing our ability to quantify the impact of adequate care in terms of outcomes. The use of standardized instruments (scales), both of a specific type (focused on the pain) and of a generic type (quality measures of life), as well as the implementation of other measures aimed to capture the results in terms of consumption of resources and medical care, has made it possible, when required, to assess the overall impact of pain on the health and life of patient. Initial and ongoing assessment of pain includes the evaluation of pain intensity using a visual or numerical rating scale ranging from 0 (absence of pain) to 10 (presence of the worst imaginable pain). Other relevant factors in pain assessment include ascertaining the quality of pain, onset, and duration as well as any actions that may worsen or relive the pain. Careful patient interviews should also evaluate the extent of patient distress resulting from pain as well as various psychological or social factors.

The Pain Research Group of the WHO Collaborating Centre for Symptom Evaluation in Cancer Care has developed the Brief Pain Inventory (BPI), a pain assessment tool devised for cancer patients. The BPI measures both the intensity of pain (sensory dimension) and the interference of pain with the patient's daily activities (reactive dimension). It also queries the patient about pain relief, pain quality, and patient perception of the cause of pain.

The BPI is a powerful tool and, having demonstrated both reliability and validity across different cultures and populations, it has been adopted in many countries for clinical pain assessment, epidemiological studies, and in studies evaluating the effectiveness of pain treatment.

**Figure 5.** Pain assessment: Objective

mistakes, as correspondence between pain severity, as reported by the patient, and presence of underlying pathology, as revealed by imaging studies, is often poor. Location, radiation, quality, intensity and temporal pattern of pain should be ascertained along with provocative and palliative factors associated with pain; afterwards, the physician should map the source of pain and investigate any clues to a possible cause; finally, the following pain features should

Physical examination should be focused on the area of pain without overlooking areas of

Physical examination is followed by specific maneuvers in order to provoke or improve pain.

For instance, pain due to bone metastases may be provoked through local palpation and manipulation. Spinal cord compression resulting from epidural tumor extension represents a known challenge. Accordingly, a comprehensive neurologic examination, coupled with manual muscle testing, percussion of point of tenderness, evaluation of joint mobility, and

The assessment of psychiatric and psychosocial co-morbidities is crucial to address factors that may adversely affect pain perception and worsen patient's distress. Radiographic studies should be guided by the anamnesis and the physical examination, as well as stage of disease, patient performance status, therapeutic options, and care endpoints. When dealing with terminally ill patients, or when little would be gained by radiographic procedures, palliative measures should be implemented without putting the patient through painful, unnecessary testing. Whenever appropriate, pain treatment should be started as early as possible so that patients may be comfortable and able to complete the diagnostic procedure. Plain radiographs

Magnetic resonance imaging (MRI) of the spine and brain and computed tomography (CT) scanning of the chest and abdomen often provide the greatest amount of information. In case of pericardial effusions or biliary or urinary tract obstruction, ultrasonography may be easily accomplished with a portable device, thus avoiding radiation exposure. Electrophysiologic studies may be useful to distinguish mononeuropathies and entrapment neuropathies from plexopathies, as well as ulnar and peroneal entrapment syndromes from brachial and lumbar plexopathies, respectively. Conduction velocities, specific latencies, amplitudes, duration, and configurations of sensory and motor evoked potentials are the keys to identify and locate the neural pathology. Importantly, it should be remembered that results of electrophysiologic

The ability to measure pain implementing valid and standardized approaches has improved in the last years, increasing our ability to quantify the impact of adequate care in terms of outcomes. The use of standardized instruments (scales), both of a specific type (focused on the

studies may be normal even with significantly damaged non-myelinated fibers.

**•** Type of pain (nociceptive, neuropathic, psychogenic);

**•** Intensity (mild, moderate, severe).

of painful areas may be of value.

**•** Temporal characteristics (acute, chronic, intense episodic);

referred pain (such as the right shoulder in case of hepatic metastases).

inspection of muscle symmetry are crucial steps of any physical examination.

be identified:

With regard to specific assessment tools, the main validated scales used in oncology are the followings:


**Cristian O'Flaherty 1,2,3,\***

Received: 17 March 2020; Accepted: 25 March 2020; Published: 29 March 2020

Human infertility affects ~15% of couples worldwide, and it is now recognized that in half of these cases, the causes of infertility can be traced to men [1,2]. The spermatozoon is a terminal cell with the unique goal of delivering the paternal genome into the oocyte. This essential task for any species survival can be threatened by environmental pollutants, chemicals, drugs, smoke, toxins, radiation, diseases, and lifestyles. Oxidative stress is a common feature of the mechanism of action of these factors and conditions that negatively impact male fertility [3–7]. Indeed, the reactive oxygen species (ROS)-mediated damage to spermatozoa is a significant contributing factor to infertility in 30-80% of infertile men [8–12].

Spermatozoa are terminally differentiated cells produced in the testes during the hormone-regulated process of spermatogenesis. Two somatic cell types are critical to this process: Sertoli cells protect and support the germ cell development, whereas interstitial Leydig cells produce necessary intratesticular steroids (e.g., testosterone) [13,14]. After their release from the testis, spermatozoa complete their maturation during the transit through the epididymis. There, they acquire the potential for motility and fertility through extensive morphological and biochemical modifications [15]. After ejaculation, spermatozoa must undergo the complex and timely process of capacitation that involves ionic, metabolic, and membrane changes, including the production of ROS at low concentrations [16,17]. Capacitation allows spermatozoa to bind to the zona pellucida that surrounds the oocyte and induce the acrosome reaction [18], an exocytotic event by which proteolytic enzymes (e.g., acrosin and hyaluronidase) are released. Thus, the spermatozoon penetrates the zona pellucida and reaches and fuses with the oocyte. Failure to undergo sperm capacitation and/or acrosome reaction is associated with infertility [19,20].

A key feature of sperm capacitation is the production of ROS at very low and controlled levels by the spermatozoon. This essential phenomenon for the acquisition of the fertility ability was first reported in humans [21], bovine [22], and equine [23] spermatozoa, and then confirmed by others (see [24] for more information). ROS play the role of second messengers and act in most of the known signal transduction pathways involved in this complex phenomenon [25–27]. Sperm capacitation is a redox-regulated process. Peroxiredoxins (PRDXs) play a crucial role in maintaining low levels of intracellular ROS to allow the achievement of fertilizing ability by the spermatozoon [28,29].

Oxidative stress can promote detrimental changes during spermatogenesis, epididymal maturation, and sperm capacitation that can lead to infertility [30–35]. Lipid peroxidation of the sperm plasma membrane is one of the first described oxidative damage associated with low sperm quality and infertility [36,37]. 4-hydroxynonenal, a subproduct of lipid peroxidation, forms adducts with proteins and DNA, impairing sperm mitochondrial function and promoting mutations in the sperm genome [38]. PRDX6, a unique antioxidant with peroxidase and calcium-independent phospholipase A2, is a key element in the antioxidant defence to protect sperm membranes and DNA from oxidative damage [39,40]. Oxidative damage to the paternal genome has been reported in humans and animals and associated with fertility failure [41–44]. Redox-dependent protein modifications are related to low sperm quality and infertility [45–47]. The reproductive system is equipped with antioxidant enzymes to avoid

the adverse e ffects of high levels of ROS during the production and maturation of spermatozoa. Di fferent studies have addressed the consequences of the absence of antioxidant enzymes on male reproduction (for details see [48]), and from knockout mouse models, we learn the critical need of superoxide dismutase, glutathione peroxidases, thioredoxins, and PRDXs to produce a healthy and fertile spermatozoa in young adult and aging males [32,41,49–52].

The decline of fertility and the increase of abnormalities in the semen of men that is observed over more than two decades is worrisome. However, we still do not have su fficient information to understand why this is happening [53–55]. The exposure environmental toxicants could partly explain this phenomenon, but there is still a significant amount of uncertainty regarding the possible causes of the decrease in sperm quality over the years [53,55]. It is an established trend that men are delaying fatherhood due to professional reasons, and scientific data from studies in animals and humans revealed that sperm quality worsens as men age. There is increasing evidence that children fathered by 50-year-old-or older men are prone to manifest a variety of disorders that can be linked to significant mutations of the paternal genome [56].

This Special Issue on ROS and male fertility is composed of four original contributions that provide new data on the role of SOD [57] and PRDXs [58] as essential antioxidants in the epididymis, and PRDXs as novel players in the protection of gonocytes against oxidative stress [59] and the participation of glutathione-S transferase omega 2 in the regulation of sperm function during capacitation [60]. The Special Issue is completed with six review articles that provide an update on the molecular changes induced by oxidative stress that impairs human sperm motility [61], the importance of ROS in determining the functionality of spermatozoa and situations in which oxidative stress occurs and impacts on male fertility [24], the oxidation of the sperm nucleus and the impact of oxidative stress on the paternal genome [62], the importance of using appropriate tools to study the role of ROS in sperm and infertility [63], and an exhaustive evaluation of ROS production and its relevance in male fertility and antioxidant therapy [64]. The characterization of the redox regulation and e ffects of oxidative stress in equine spermatozoa is also included in this Special Issue [65].

Many groundbreaking studies have contributed to our understanding of the field of ROS in male fertility. It is undeniable that these reactive molecules play an essential role in both physiological and pathological mechanisms of the male reproductive system. Antioxidant therapy is a common clinical strategy to improve sperm quality and function in infertile men [66,67]. However, there are controversial results regarding the e fficacy of these treatments. Some controlled trials suggested that such treatments are beneficial to achieve live births [66], whereas others did not show any benefit [68]. This discrepancy is likely based on the lack of tools in clinics to establish whether oxidative stress is responsible for the infertility of a given patient. Thus, more fundamental and clinical research is needed to comprehend how ROS modulate male fertility to design better diagnostic tools and therapeutic strategies to fight against male infertility.

**Funding:** Original research by the author of this editorial was supported by the Canadian Institutes of Health Research (CIHR), operating grant # MOP133661 to CO.

**Conflicts of Interest:** The author declares no conflict of interest.


**1. Introduction**

Membranes are used in desalination or water treatment to separate pollutants from water based on characteristics such as size or charge. Since the late 1950s, reverse osmosis, nanofiltration, ultrafiltration, and microfiltration techniques have been used in water and wastewater treatment and in different application areas. Rapid developments in membrane technologies in the last 50 years have made these technologies the preferred technologies in water and wastewater treatment. However, traditional membranes have a number of disadvantages, including fouling both on surfaces and in internal structures, uncontrollable pore size, and membrane features.

 production technology have also increased the use of industries, such as chemistry, petrochemistry, mineral propharmacy, electronics, paper, etc. Although membrane filters

are used as an alternative water recovery process in many areas, clogging is still one of the biggest problems. Clogging in membranes limits the membrane's permeability [1]. In other words, it causes a decrease in the flux passing through the membrane per unit membrane pressure and, therefore, in the production of treated clean water per unit membrane area. In membranes designed for particulate matter or microbial removal, clogging occurs as a result of the accumulation of materials on the membrane surface or in the membrane pores.

Smart membranes, also known as stimuli-responsive membranes, have recently attracted attention due to their selectivity, tunable permeability, and tunable and/or reversible attributes [2]. This new generation of smart membranes is created by integrating various stimuli-responsive materials into membrane substrates. These multi-functional smart membranes can self-adjust their physical and chemical features in response to environmental signals such as temperature, pH, light, and other stimuli [3].

Because of their smart structures, they have the potential to improve performance by providing high selectivity without reducing the permeability, high mechanical stability, and high resistance against fouling, and can meet requirements such as molecular weight cut-off (MWCO), removal efficiencies, and wastewater quality.

This review of smart membranes is briefly summarized.

### **2. Kinds of Smart Membranes**

Developments

 processes in many

membrane

cessing, food  in membrane

biotechnology,

Positively and negatively responsive smart membranes can self-adjust their physical and chemical properties in response to environmental signals such as temperature, pH, light, and other stimuli.

The responsive gating function is divided into two models: positively and negatively responsive smart membranes [4].

Figure 1 represents positively responsive smart membranes.

**Figure 1.** Positively responsive smart membranes ( **A**). The permeability of the membrane increases in response to the presence or increase of a stimulus. (**B**) Temperature-responsive, ( **C**) pH-responsive, (**D**) specific ion-responsive, (**E**) molecule-responsive, (**F**) UV light-responsive, ( **G**) glucose-responsive, and ( **H**) magnetic-responsive [4].

Figure 2 represents negatively responsive smart membranes.

**Figure 2.** Negatively responsive smart membranes. (**A**) The permeability of the membrane decreases in response to the presence or increase of a stimulus. (**B**) Thermo-responsive, (**C**) pH-responsive, (**D**) ion-responsive, (**E**) molecule-responsive, (**F**) UV light-responsive, (**G**) ion strength-responsive, and (**H**) redox-responsive [4].


**5. Co-liquefaction of coal and biomass**

raw MB coal. Thus, based on Equation 2, it is estimated that about 89% of raw MB coal would

In order to reduce operation cost and capital, and also to increase coal liquefaction efficiency, the liquefaction processes were usually carried out at less severe conditions. However, in most of coal liquefaction, the temperature used was higher than 400 °C and at relatively higher pressures. Thus, many attempts have been made by researchers to establish and develop methods of liquefying coals at lower temperature and pressure. Mukah Balingian, a low rank Malaysian coal, was extensively used in liquefaction study [29]. In the investigation, three different types of pretreatments, i.e. solvent swelling, in-situ solvent soaking and heating and

be converted during liquefaction process.

**4. Coal liquefaction**

194 Biofuels - Status and Perspective

**Parameters Results** Maximum reflectance of vitrinite 0.40%

**Figure 4.** Correlation of coal conversion with petrofactor [37].

Total reactive maceral content (Vitrinite + Liptinite) = 91% Petrofactor 1000 x (0.40%) / (91%) = 4.40

Estimated coal conversion 100 – 2.5 (4.40) = 89%

**Table 3.** Petrofactor value and estimated conversion of raw MB coal [29].

One of the solution to the above-mentioned situations encountered with coal and biomass is by the co-liquefaction of both of them. This can also maintain the stability supply of the materials. Moreover, one of the advantages of using biomass is that it accelerates the thermal decomposition of coal macromolecular structure by reducing the severe reaction conditions, especially the temperature during liquefaction. By producing smaller molecular fragments, it enables the combination with the large fractions produced from coal decomposition and simultaneously terminate the cross-linking reaction between them (this is to avoid the production of larger molecular weight products). Thus, the yield of low-molecular-weight products will be increased, oil quality improved and eventually, will reduce the yield of the residue during co-liquefaction process [25].

Most of the research works done for alternative energy sources have shown that, in general, co-processing or known as co-liquefaction of coal with biomass-type wastes has a positive effect on the liquefaction yields and product quality [14, 15]. Co-liquefaction of coal with biomass has gained increasing research interest due to the growing concerns over greenhouse gas emissions [28]. Because biomass materials also contain abundant hydrogen, co-liquefaction of coal and biomass waste is one of the best and feasible option to reduce the consumption of hydrogen as well as to avoid severe reaction conditions during co-liquefaction. Till today, however, very limited research work has been carried out in this field.

The mechanism of co-liquefaction of coal and biomass is believed to be a radical process. Thus, the unstable free radical fragments which are formed during pyrolysis of coal and biomass will be stabilized by active hydrogen contributed from biomass to form hydrogenation/lowermolecular-weight products. Researchers anticipated that there is a synergistic effect (synergy is two or more things functioning together to produce a result not independently obtainable) in the co-thermolysis process, and the yield of solid products from co-thermolysis is different from the arithmetic calculated value [1].

Hua *et al.* [38] carried out co-liquefaction of coal and rice straw and believed that there exists a synergistic effect during co-pyrolysis of Shenfu coal and rice straw. Shui *et al.* [39] investigated the co-liquefaction behavior of a sub-bituminous coal and sawdust. They found that the thermolysis of Shenhua coal was accelerated by sawdust and more volatile matter was released from the coal molecular structure during the co-thermolysis process. In another study, Guo *et al.* [25] also investigated the synergistic effect existence in the co-liquefaction of coal and biomass. They found that a positive synergistic effect during the process actually existed. Thus, they concluded that the synergistic effect depends on several factors, i.e. (i) coal rank, (ii) liquefaction conditions and (iii) different liquefaction products.

The liquefaction process of coal and biomass materials, which is known as "Co-liquefaction", has not been developed in Malaysia. The yields and quality (especially H/C ratio) of the liquid products obtained from coal under less severe liquefaction conditions (at lower temperature and pressure) can be improved with co-liquefaction of coal and biomass. Therefore, the cost of oil produced from direct coal liquefaction can be reduced significantly. The process can make full use of hydrogen in biomass, thus decreasing the consumption of hydrogen and moderating the conditions of DCL [1].

Some important parameters for co-liquefaction are the materials used, the design of the reactor, pressure, extraction solvent, temperature, holding time and catalyst used. Hua et al. [38] reported that the rice straw contains 68.3 w/% of volatile matter and resulted in 60.3% of oil at 420 °C. However, rice straw contains high amount of silica. Shui et al. [39] reported that fir sawdust contains 78.2 w/% of votalite matter and results in 55.2% of oil at 420 °C. However, fir occurs in mountains over most of the range. Guo et al. [25] reported that poplar sawdust contains 80.27 w/% of volatile matter and results in 59.19% of oil at 360 °C. However, high tannic acid content is present in poplar. Basic properties of crude rubber seed oil and crude palm oil blend as a potential feedstock for biodiesel production with enhanced cold flow characteristics were studied by Yusup et al. [40] and the inspections determined that the rubber seed oil can be used in the current diesel machines with no alteration required, confirming the adaptability of the produced biodiesel to the current standards. This shows that the charac‐ teristic of rubber seed as a biofuel material is more suitable than rice straw, fir sawdust, poplar sawdust and other biomass that contains less oil.

Hua et al. also [38] suggest that the FeS catalyst used has a good catalytic hydrogenation activity on rice straw, but the drawback of this catalyst is that it is low in basicity to reduce carboxylic acid present in the vegetable oil. An alternative for the FeS usage as a catalyst is by using dolomite. Dolomite is a natural rock found abundantly in certain areas of Malaysia and Thailand. Due to its very low cost to produce and being easy to obtain, the main domestic usage of dolomite is currently in the landfill site and in cement manufacturing. CaCO3 and MgCO3 are the major components of dolomite with a small amount of silica and ferrite. In a simple calcination process at high temperatures, the CO3 group in pure CaCO3 will decompose to produce CaO (which is highly basic) and MgO [41].

Guo et al. [25] state that the temperature is the most important factor during liquefaction. Shui *et al*. [39] reported that the main pyrolysis temperature range of Shenhua coal (a sub-bitumi‐ nous coal) (362 – 750 °C) is much higher than that of sawdust (260 – 420 °C), and the releasing rate of volatile matter of Shenhua coal is much lower than that of sawdust. Hua et al. [38] reported that the pyrolysis temperature of Shenhua Coal is in the range of 360 – 750 °C; however, the pyrolysis temperature of biomass is in the range of 250 – 400 °C.

Hence, an attempt should be made for co-liquefaction of low-rank Malaysian coal and biomass wastes such as rubber tree wastes (rubber seed, rubber seed pod or rubberwood) for the production of alternative fuels and other important purposes such as chemical feedstocks. Working on the area of energy has now become the priority in most of laboratories worldwide. In Malaysia particularly, under the New Economic Model (NEM), innovation and research is regarded as crucial factor to propel the industry. The research in this area certainly contributes to the increases in energy sector that part of National Key Economic Area (NKEA). Further‐ more, a competitive domestic economy can be created as part of Strategic Reform Initiative (SRI) [42].


**Analytical, Numerical and Experimental Studies on Stability of Three-Segment Compression Members with Pinned Ends**

Seval Pinarbasi Cuhadaroglu, Erkan Akpinar, Fuad Okay, Hilal Meydanli Atalay and Sevket Ozden

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/45807


*2.6.3. Purification of Azurin on ion – Exchange (anionic) chromatography*

## *<IP_ADDRESS>. Chromatography on CM cellulose*

The CM cellulose beads from Sigma–Aldrich (Kolkata, India) were equilibrated for overnight in the ammonium acetate buffer pH 3.9 adjusting the pH by 0.05M acetic acid with 2M NH3.After swelling, the beads were packed in a 5cm x 15cm glass column and washed for ten times of the column volume. Gently one ml of the sample added (Fraction (e) collected from G-75) over the top of the column and left it for 5-10 minutes to bind the protein inside the beads. After 10 minutes the column was eluted with ammonium acetate buffer pH 4.65 [12-14].

## *2.6.4. Characterization of Azurin (purified from P. aeruginosa MTCC2453)*

## *<IP_ADDRESS>. Molecular weight determination by matrix-assisted laser desorption/ionization time of flight (MALDI-ToF)*

The most successful method to analyze biopolymers such as, proteins, peptides, sugars and large organic molecules which are tend to be fragile and fragment when ionized by more conventional ionization methods [15]. The Fractions collected from G-25, G-75 and CM cellulose were performed MALDI for molecular weight determination. Two micro liter from each fraction of the chromatography was added with 20µl of 3, 5-Dimethoxy, 4-Hydroxy cinnamic acid otherwise called as sinnapinic acid (Sigma-Aldrich. Kolkata, India). Tiny spots were made on silver plate and kept for drying for 4-6 hours to drain the water molecules. Further spots were dried with a vacuum drier to make a crystalline molecule. After drying the samples were placed in the MALDI-ToF chamber (Voyager De pro, applied systems Illinois, USA) for analysis by using nitrogen laser at 337 nm.


**1. Introduction**

Normally, you already know the polyimide (PI) and the super engineering plastics derivative from PI are one of best high resistive dielectric materials for any application, for example print board, motor windings, surface materials of spacecraft, and so on. However, sometimes, the PI have breakdown phenomena under high voltage application with high temperature and humidity condition. It is considered that the origin of breakdown is the electric filed enhancement in the bulk or high growth of conduction current during the bulk by the homo charges injection form the electrode, or the hetero charges accumulation due to hydrolysis by surround high humidity environment. Furthermore, concerning the radioactive rays irradiated PI, the huge space charge polarization is produced. And then, sometimes, PI has a breakdown phenomenon due to irradiation.

To understand the dielectric characteristic for the serve condition, it is important that the space charge accumulation phenomena are observed. Therefore, in this chapter, we introduce the space charge accumulation in the bulks under the high electric filed, high temperature, high humidity and radiation environment.


*3.2. Electrocatalysis*

Besides the use of POM@MOF hybrids in organocatalysis, POMs also exhibit interesting electrocatalytic properties as they can undergo fast and reversible multi-electron transfers [157]. Within this context, POMs have already shown great potential in the electrochemical oxygen evolution reaction (OER) in a homogenous manner [158]. Despite the remarkable progress in this field, there are only a few reports on the encapsulation of POMs in the cages of MOFs for electrocatalytic water oxidation, as can be seen in Table 2. This is probably due to the fact that the majority of MOFs possess a low electrical conductivity and high hydrophobicity. The first report on the encapsulation of an unsubstituted Keggin POM in a MOF to perform electrocatalytic water oxidation was reported by Das et al. [137]. More specifically, a one-pot synthesis was performed to include the [CoW12 O40] 6− anion in the size matching cage of ZIF-8 (see Figure 13). During the electrochemical measurements, performed at pH 1.9, the authors observed a clear shift to a less anodic potential for the redox CoIII/CoII couple in the cyclic voltammogram of POM@MOF with respect to that of the uncapsulated POM (from 1.14 V for the Keggin POM to 0.97 V for the composite material). In addition to this, the POM@MOF catalyst exhibited an excellent stability as only a very small drop in the catalytic current was observed after 1000 catalytic cycles and no leaching of Co species was observed. It is, however, important to note here that, although the catalyst exhibited a high turnover frequency (TOF = 12.5 s−1 based on the quantitative oxygen evolution) and an excellent faradaic e fficiency of 95.7%, a rather high overpotential was required (784.19 mV at a current density of 1 mA cm−2).

**Figure 13.** Encapsulation of an inactive Keggin POM in ZIF-8 to become an active oxygen evolution reaction (OER) catalyst. Reprinted with permission from [137]. Copyright (2018), John Wiley and Sons.

In a very recent report of the same group, a redox inactive SiW12 POM was used to lower the required overpotential [138]. The co-encapsulation of this POM together with the true catalyst, an Fe(salen) complex, within ZIF-8 resulted in a decrease of the overpotential of more than 150 mV. In the absence of the encapsulated POM, the Fe-salen@ZIF-8 required an overpotential of 672.9 mV to attain a current density of 1 mA cm−2, while in the presence of the POM, the overpotential decreased to 516 mV. The authors attributed this observation to the fact that the POM not only increased the hydrophilicity of the catalyst and facilitated the charge conduction in ZIF-8, but also ensured a higher loading of the Fe-salen complex within ZIF-8. Another way to decrease this overpotential for oxygen evolution and thus improve the hydrogen production efficiency was reported by Pang and co-workers [139]. In this work, the authors demonstrated the successful coating of ZIF-67 with a catalytically active Keggin POM, H3PW12 O40. The unique yolk/shell structure of the ZIF-67@POM catalyst ensured a high electrical conductivity and fast charge transfer, which resulted in a significant reduction of the overpotential. From all of the examined ZIF-67@POM hybrids, the 6-ZIF-67@POM catalyst exhibited the smallest Tafel slope (58 mV dec−1) and lowest overpotential values (287, 313, and 338 mV at current densities of 10, 20, and 30 mA cm−2, respectively), which are even comparable to those observed for RuO2, which is one of the most efficient and well-known electrocatalysts for the OER reaction [159].

Besides these few examples on OER, POMs have also shown great potential in the second half reaction for water-splitting, namely the hydrogen evolution reaction (HER) [160]. However, to solve their shortcomings, particularly the limited stability of POMs in the required highly acidic pH for HER, Zhang et al. encapsulated POMs in metal–organic nanotubes (MONTs), which can be considered as a special kind of MOF [140,141]. Upon encapsulation of the POMs, using a one-pot synthesis method, the chemical stability of both the POM and MONTs increased. The POMs served as a kind of template to construct the MONTs, while the MONTs ensured a sort of a shield to increase the chemical stability of the POM. The best POM@MONTs electrocatalyst displayed an overpotential of 131 mV (at a current density of 10 mA cm−2), which is far more superior than other POM-based MOFs (which showed overpotentials above 200 mV) [161].