**2. Dissipative Self-Organization is a Concept for Autonomous Mechanical Work**

Atkins' *Physical Chemistry* describes mechanical work as 'the transfer of energy that makes use of organized motion in the surroundings' [4] and distinguishes it from the transfer of energy to disordered thermal motion. In other words, to create molecular devices capable of performing useful work, it is necessary to provide the devices with proportions that will create organized movements in the surroundings (Figure 1a). Hence, a single synthetic molecular motor is too small to achieve beneficial mechanical work independently and, therefore, the motor molecule must either be positioned in a heterogeneous field or the molecules must be assembled [5]. This text considers the latter approach in detail. If a large number of molecules are merely assembled to increase the device's size, the movement of molecules is time-averaged and the molecules show no macroscopic changes under a steady condition (Figure 1b). This state is referred to as a chemical or near-chemical equilibrium, and under it, the molecules cannot create organized movements in their surroundings. In other words, to create molecular devices capable of performing beneficial work, it is necessary to introduce 'a mechanism in which the devices continually demonstrate macroscopic changes even if the environment is in a steady state' (Figure 1c). This mechanism is referred to as dissipative self-organization. In short, it is a mechanism for generating macroscopic motions via movement at the molecular level. The generated motion also has the potential to create motion in a larger hierarchy. Furthermore, due to the ability of the self-continuous action to an external object, devices that exhibit dissipative self-organization can act as an oscillation generator to actuate the repetitive motion of equilibrial materials. The creation of such molecular technology will lead to the invention of autonomous molecular robots, autonomous molecular pumps, and autonomous molecular information processors.

**Figure 1. How to compel molecular materials to work.** (**a**) A small molecular motor cannot carry out mechanical work for several reasons, one of which is that the transferred energy is converted to thermal energy immediately. (**b**) A stimuli-responsive material can perform work only while relaxing the instability motivated by a shift in an external condition. (**c**) Autonomous transformation of a molecular system can perform work via energy transformation. The green circles denote objects subjected to force in the surroundings.

#### **3. Dissipative Self-Organization for Robustness and Energy Conversion**

In chemistry, transient aspects of the system are generally described by reaction rate equations. Here, we hypothetically consider chemical reactions in a homogeneous solution, where (a) the symmetry of reactions is broken, and (b) the kinetic constants (*k*s) are consistent. The flaws of the hypothesis will be discussed below and in [6]. An autocatalytic reaction, in which the A → B reaction is accelerated by B, is introduced as a symmetry-broken reaction [7]. The reaction with the co-existence of a non-autocatalytic process, the kinetics equation of which is described in Appendix A, is shown in Figure 2a [6]. After introducing the logistic curve, general textbooks of nonlinear chemistry describe Lotka–Volterra-type dynamics: the open reaction of A → B → C → D with two autocatalytic steps demonstrates oscillatory behavior in composition (Figure 2b) [3,8]. On the other hand, we consider a triangular type reaction of A → B → C → A, aiming to distinguish the system's boundary.

**Figure 2. Numerical analyses for composition curves of reactions involving autocatalysis.** (**a**) Logistictype composition curve. (**b**) Lotka–Volterra-type composition oscillation. (**c**) Composition curve for a triangle reaction including one autocatalytic process. (**d**,**e**) Composition curves for triangle reactions, including two autocatalytic processes with and without considering reverse processes, respectively. (**f**,**g**) Oscillatory composition curves in triangle reactions, including three autocatalytic processes with and without considering reverse processes, respectively. (**h**) The variation in total heat of formations of A, B, and C while the change is shown in (**g**). Because the exteriorization of energy from the system occurs when the sum of the heat of formations decreases, an external energy supply is required to maintain the oscillation. Similarly, all calculations assumed consistent kinetic constants, meaning that an adequate energy supply and relevant emissions exist, although the fact is not indicated in the schemes. The red, orange, and blue lines denote compounds A, B, and C, respectively. The equations for the numerical analysis are described in Appendix A.

To simplify the discussion, we present here the simulation results while ignoring co-existing non-autocatalytic sub-routes within the autocatalytic steps [6]. In triangular-type reactions with one or two autocatalytic steps, it is easy to achieve equilibrium, as shown in Figure 2c,d. Even if we ignore the reverse processes, the reaction reaches equilibrium, as shown in Figure 2e. On the other hand, in reactions with three autocatalytic processes, periodic oscillations in the composition ratio are autonomously demonstrated, as shown in Figure 2f (taking into account reverse processes of autocatalytic paths) and Figure 2g (ignoring them). As described here, the kinetic equations indicate that multi-molecular oscillations may be generated by the contribution of plural nonlinear processes, and that the feature is emasculated by the coexistence of reverse processes. Note that autocatalysis is employed only because it is a well-known and easy-to-calculate nonlinear chemical process—other symmetry-broken phenomena, especially those with large nonlinearity and irreversibility, may contribute to realizing the oscillatory system.

However, the enthalpy of the system varies with oscillation (Figure 2h). The actual system dissipates thermal energy outside the system when the enthalpy decreases, and the periodic behavior is relaxed and terminated. This fact suggests that a supply of convertible energy from outside the system is required to develop the oscillation. In summary, a system with autonomous multi-molecular oscillation can be realized as shown in Scheme 1. The reaction scheme is somewhat similar to a catalytic reaction and a fluorescence scheme; the difference is that the change is in the distribution of components or in the molecular-level structure, and that the nonlinear phenomena are involved in the scheme and act inter- or intra-molecularly.

This temporal pattern in a multi-molecular system under continuous energy supply and periodic energy dissipation is referred to as a dissipative structure; while making cyclic transitions (A → B → C → A) at the molecular level, periodic behaviors are generated as a molecular ensemble, the time scale of which is larger than molecular-level conversion. Although we cannot predict when a chemical reaction happens at the molecular level, we can predict when the macroscopic change occurs by observing the robust temporal pattern. Even if the reaction solution is reduced by half or is frozen temporarily in the middle of the reaction, the autonomous oscillation is robustly maintained. These features are characteristic of dissipative structures.

In a homogeneous system, the variation of the system's enthalpy is dissipated as thermal energy because the system cannot form organized motion. Regarding devices with shapes (such as molecular assemblies), variation in enthalpy can be used to apply mechanical work to the surroundings. This energy conversion function at the multi-molecular scale is the essential attraction of dissipative self-organization with molecular self-assembly.

**Scheme 1.** Conceptual scheme for an autonomous system.

#### **4. Research Aiming Mechanical Work with Energy Conversion**

Molecular machines and motors, which are defined as molecules that are expected to convert supplied energy into mechanical forces and motion, have attracted considerable attention among chemists [9–14]. Molecules that reversibly alter their equilibrium structures, triggered by shifts in external conditions, are known as molecular machines, distinguishing them from molecular motors, a term denoting molecules that maintain their symmetry-broken motion under the continuous supply of energy [12,13]. In contrast to the molecular machines, the symmetry-broken motion of molecular motors may perform autonomous work in molecular-level space if in contact with another object. Feringa's research into nano-cars may provide one example of this, although his team's experiment was conducted using an intermittent electric current rather than continuous light waves [15]. Photo-induced ion or electron transportation across membranes [16,17] provides further instances of this phenomenon [5]. However, to attain more significant autonomous work at the multi-molecular scale, the concept of dissipative self-organization is required. Even if we gather molecular motors and supply energy, the motions are time-averaged and the energy is dissipated as thermal energy. In fact, according

to Feringa's report, the motion of a glass-rod on a molecular motor-containing liquid crystal was terminated despite the continuous energy supply [18,19], similar to the system employing molecular machines [20,21]. Therefore, his collaborators are currently directing their efforts to the design of multi-molecular systems where the motors are synchronized to realize mechanical work at the macroscopic level [22].

As mentioned here and elsewhere recently [14,23], the chemical challenge to active work lies in the creation of macroscopic and self-continuous motion. However, one successful example has already been published [24]. This approach, which did not use a chiral molecule, differed from the strategies of other chemists. Molecular-level chirality (e.g., chirality due to an asymmetric form of carbon) is not required for macroscopic objects to move, whereas symmetry-breaking is a critical factor in their motion. Herein, the autonomous flipping and swimming of a submillimeter-size molecular-assembly is introduced [24–26].

The submillimeter-size assembly of an achiral azobenzene derivative (**AZ**) showed an autonomous bending-unbending motion under continuous light irradiation (Figure 3). The photochromic compound repetitively changes its molecular structure between *trans*- and *cis*-isomers under light irradiation. Ordinarily, repetitive photoisomerization yields a mixture of isomers, the composition ratio of which is constant and depends on the photoreaction rates. However, in the study, a phase transition occurred before the ratio achieved the equilibrium value, switching the reaction rates. Coupling the sets of photoisomerization and its induced phase transition led to a periodic transition consisting of an increase in the *cis*-isomer, a morphological change, a decrease in the *cis*-isomer, and then to a morphological recovery [24,27]. The enthalpy also changed periodically with the cyclic process [25]; the cycle enabled autonomous energy conversion from light to mechanical work. At the bending motion, another asymmetry defines the direction of the transformation. According to the single-crystal analysis [25], the space group of the assembly was *P*1, and it was assumed that the asymmetry concerns the direction of bending. In addition, some break in symmetry is required to produce an autonomous swimming motion: if the bending-and-unbending motion is spatially reciprocal, it is impossible for the assembly to swim in a Newtonian fluid, as the Scallop theorem indicates [28]. The directional swimming of the assembly indicated that the morphological changes occurred in a non-reciprocal manner [26]. Furthermore, the authors also demonstrated signal-dependent pattern formation, a concept that can be applied to molecular-based information processors [25].

Applying stimuli-responsive materials, oscillatory motions, and directional motions has also been reported [29–41]. Stimuli-responsive materials generally terminate their motion when the systems reach equilibrium. The oscillations in those studies were motivated by the coupling of the directionality of external energy-supply and the time-delayed transition of materials [27,39]. Therefore, we can anticipate that the motions are characterized and controllable by the external conditions, but they lack robustness—for example, adjustment of the energy source position seriously affects the mechanical behavior [27]. Some researchers wrongly regard this feature as an instance of taxis, but it actually arises from a lack of self-excitation. On the other hand, dissipative self-organized materials possess the feature of autonomy. The sustainability and directionality of the movements are guaranteed by the internal factors of the materials. The series of studies of BZ-hydrogels, which are hydrogels periodically repeating swelling and unswelling through the Belousov–Zhabotinsky (BZ) reaction, clearly indicated the superiorities of dissipative self-organization for mechanical device applications [42,43].

**Figure 3. Self-sustaining mechanical motion of azobenzene assembly under continuous blue-light irradiation** [24,25]. (**a**) Molecular-level repetitive transformation of the component molecule (an achiral azobenzene derivative, **AZ**). (**b**) Micrographs of the macroscopic autonomous flipping motion under light irradiation. (**c**) Schematic energy diagram for the autonomous cycle; mechanical work was performed at the steps of exergonic morphological change. All figures were reproduced from the original data with permission from Wiley-VCH, 2016.

## **5. Research into Self-Developing Molecular Systems: The Chemical Model of Cell Amplification**

Cell amplification is also intrinsic to living things [1,2,44–46]. The pioneering study of the chemical model of cell amplification was reported by Luisi [47,48]. The team monitored the increase in oleate assembly in water following the addition of oleic anhydride and concluded that the autocatalytic hydrolysis of the anhydride occurred in the oleate assembly to form oleic acid [48]. Inspired by the study, Sugawara's group designed a system where a membrane molecule formed from a bipolar amphiphile via hydrolysis, catalyzed by a molecule embedded in the vesicular membrane, and, thereby, captured the growth-and-division dynamics of vesicular assemblies [49,50]. In addition, they succeeded in demonstrating the amplification of DNA via a polymerase chain reaction within the vesicles [51,52]. Furthermore, the group firstly realized autocatalytic vesicular amplification systems, via organic

synthesis [53,54]. Following these studies, Devaraj's group [55] also reported the production of an autocatalytic membrane amplification system, in which a molecular catalyst formed spontaneously.

Considering the intrinsic feature of cell amplification, the concept of autocatalysis is fundamental [56,57], and all self-replications occur in an autocatalytic manner [7,58–71]. In the vesicular self-reproduction system without autocatalysis, the generated vesicles were different from the original ones—the catalytic ratio decreased proportionally in each generation, and the system tended to reach equilibrium, even if the precursor for the membrane molecule was continuously supplied (Figure 4a) [49,50,52]. This behavior is the same as inanimate systems. On the other hand, in the autocatalytic system, the catalytic ability is maintained across generations. When the precursor is supplied continuously or an excess amount of precursor is presented, or under both conditions, the individual vesicle repeats its growth and division periodically (Figure 4b) [53–55].

**Figure 4.** The difference between (**a**) non-autocatalytic and (**b**) autocatalytic vesicular self-reproduction.

Besides, as Fletcher comments on his autocatalytic micellar system [72,73], a cyclic reaction with an autocatalytic vesicular formation maintains vesicle numbers in an open system; this scheme is represented in Figure 2a,c. Developing this concept, we would like to consider the existence of one additional autocatalytic reaction: the system where the vesicle becomes prey to a larger self-assembly (the consumption ratio is proportional to the number of the larger assembly) and the larger self-assembly decomposes. The reaction equation of the system is complicated because of the diversity in molecular numbers in each vesicle. Nevertheless, it can be expected that the behavior can be represented by the Lotka–Volterra model (if the decomposition is exhausted to the exterior of the dispersion; Figure 2b) or the similar model shown in Section 3 (if the component is recycled autocatalytically by accepting energy from outside the system; Figure 2f,g). Under such conditions, a spatially and temporally larger oscillation than the vesicular growth-division periodicity will be generated (Figure 5). This predator–prey concept is linked to the robustness of nature in an overall sense.

**Figure 5. Conceptual illustration for a hierarchical system composed of autocatalytic assembling processes.** Spatially and temporally larger oscillation generating a molecular assembly that appears and disappears repetitively.

#### **6. Conclusions and Perspectives**

Dissipative self-organization is the concept of the cooperation of dynamics to form larger dynamic systems [3]. At the nano level, the combination of thermal fluctuation, a symmetry-breaking phenomenon, and a supply of energy results in the formation of a tiny but organized dynamic system. Once organized dynamics are generated, more robustness and more significant organized motion are formed if symmetry-breaking processes are involved. Through iterative self-organization, a highly hierarchical molecular world is constructed. The symmetry-breaking phenomena contribute to making the system differ from the equilibrium structure. Here, a supply of convertible energy is required to realize self-organization, and both the reception and the dissipation of the energy occur autonomously. The concept of dissipative self-organization is directly linked to the chemical energy conversion to achieve autonomous mechanical functions.

We chemists ordinarily encounter self-organized phenomena. If we consider a molecule to be a thermodynamic system composed of electrons and nuclei, the system demonstrates self-organized behavior whether the molecule is termed a machine or not. However, such systems are too small to perform mechanical work, and the assembly of molecules is, thus, proposed to meet this function. However, controlling symmetry-breaking at the multi-molecular level is a complex task; the artificial system of a molecular assembly tends to form its equilibrial structure. The BZ reaction that was applied to mechanical gel [42,43] and the recent azobenzene-assembly system [24–26] provide successful examples. The creation of chemically fueled mechanical work is particularly challenging; if we outdistance the system from the thermal fluctuation level by consuming the dilute energy of chemical compounds, we have to recruit effective ratcheting phenomena.

A recently proposed concept, 'dissipative self-assembly', seems to share the same issues [74–79]. However, from the author's standpoint, the claims of dissipative self-assembly are still unclear and weak in the aspect of the distancing from equilibrium; most of the papers reported consecutive reactions where the intermedium products were assemblies and claimed that the assembled state can be maintained through continuous substance supply [72,73,80–87]. The structure of such nonequilibrium systems is not a dissipative structure, according to Prigogine [3]. In this context, the supplied energy is consumed to sustain the assembly, but not for autonomous tasks [88,89]. To imitate living dynamics clearly, we have to employ one or more symmetry-breaking effects to replace the system from the

equilibrium structure at the tentative state to a nonequilibrium resume [90]; according to Chapter 7 in reference 3 and the references therein, at least a cubic nonlinearity in the rate equations is required to destabilize the thermodynamic branch.

However, a negative attitude to the current difficulties in imitating the intrinsic features of living dynamics is misplaced. One of the reasons for the struggle to reproduce autonomous dynamics is that chemists attempt to create mechanical materials using switchable molecules, so-called molecular machines. Such molecules are convenient for chemists because their status is easily controlled. Yet in living things, it is not switching motions but continuous motions that are able to do power- autonomous work. In other words, enzymes work with ratcheting mechanisms to prevent the system from attaining equilibrium. By imitating the function of enzymes [91–93]—molecular-recognition with nonlinear adaptation and repetitive transformation with energy conversion—and by assembling the synthesized products [23], the author believes that we chemists will attain breakthroughs in nanotechnology; indeed, research based on this perspective has recently begun.

**Funding:** This research was funded by Japan society for the promotion of science (JSPS) KAKENHI (Scientific Research on Innovative Areas), Grant Numbers JP18H05423 "Molecular Engine", JP17H05346 "Coordination Asymmetry", and JP20H04622 "Discrete Geometric Analysis for Materials Design".

**Acknowledgments:** The author thanks Professor Sadamu Takeda and Dr. Goro Maruta for their fruitful discussions. **Conflicts of Interest:** The author declares no conflict of interest.

#### **Appendix A**

Each graph in Figure 2 was the result of numerical analyses of Equations (A1)–(A7). The symbols of χs, *k*s, and *t*, denote the molar fractions, kinetic constants, and time, respectively. The term *k*XY indicates the kinetic constant of the autocatalytic step of X→Y. The calculated timespan was from 0 to 1000 (arbitrary unit). The 'N's denote the relative number of portions. To solve the ordinary differential equation, the ODE45 method was used and operated by Matlab 2020a software provided by The Mathworks Inc., Natick, MA, USA. For Figure 2a the following equations were used:

$$\frac{d}{dt}\chi\_{\rm B} = \left(k\_{\rm AB}\,\chi\_{\rm B} + k\_{\rm IF}\right)\chi\_{\rm A} - \left(k\_{\rm BA}\,\chi\_{\rm A} + k\_{\rm IR}\right)\,\chi\_{\rm B} \tag{A1}$$

$$
\chi\_{\mathcal{A}} = 1 - \chi\_{\mathcal{B}}.\tag{A2}
$$

For the demonstration, 0.02 and 0.01 were assigned for *k*AB and *k*BA, respectively, 1 <sup>×</sup> 10−<sup>5</sup> was assigned for *k*1F and *k*1R, and 1 was assigned for the initial molar fraction of A. For Figure 2b the following equations were used:

$$\frac{d}{dt}\mathbf{N}\_{\rm B} = k\_{\rm AB} \, \mathbf{N}\_{\rm B} - k\_{\rm BC} \, \mathbf{N}\_{\rm B} \, \mathbf{N}\_{\rm C} \, \tag{A3}$$

$$\frac{d}{dt}\mathbf{N\_{C}} = k\_{\rm BC} \,\mathbf{N\_{B}} \mathbf{N\_{c}} - k\_{\rm CD} \,\mathbf{N\_{C}}.\tag{A4}$$

For the visualization, 0.03, 0.02, and 0.1 were assigned for *k*AB, *k*BC, and *k*CD, respectively, and 0.5 was assigned for the initial numbers of B and C. For Figure 2c–g the following equations were used:

$$\frac{d}{dt}\chi\_{\rm B} = \left(k\_{\rm AB}\chi\_{\rm B} + k\_{\rm IF}\right)\chi\_{\rm A} - \left(k\_{\rm BC}\chi\_{\rm C} + k\_{\rm 2F} + k\_{\rm BA}\chi\_{\rm B} + k\_{\rm IR}\right)\chi\_{\rm B} + \left(k\_{\rm CB}\chi\_{\rm C} + k\_{\rm 2R}\right)\chi\_{\rm C} \tag{A5}$$

$$\frac{d}{dt}\chi\_{\mathbb{C}} = \left(k\_{\mathbb{BC}}\chi\_{\mathbb{C}} + k\_{\mathbb{2F}}\right)\chi\_{\mathbb{B}} - \left(k\_{\mathbb{CA}}\chi\_{\mathbb{A}} + k\_{\mathbb{3F}} + k\_{\mathbb{CB}}\chi\_{\mathbb{C}} + k\_{\mathbb{2R}}\right)\chi\_{\mathbb{C}} + \left(k\_{\mathbb{AC}}\chi\_{\mathbb{A}} + k\_{\mathbb{3R}}\right)\chi\_{\mathbb{A}}\tag{A6}$$

$$
\chi\_{\mathcal{A}} = 1 - \chi\_{\mathcal{B}} - \chi\_{\mathcal{C}}.\tag{A7}
$$

Each value for the calculations is indicated in Table A1.

**Table A1.** Values assigned to each parameter for the numerical analysis.


**Abstract**

Hansen's disease is one of the most ancient diseases that is still prevalent in the world. The causative agent, Mycobacterium leprae (*M. leprae*) has a long incubation period, clinical features after infection are identified late and these acid fast bacilli cannot be cultured – making leprosy a difficult disease to eradicate. Therefore the prevention and control of disease becomes more important. The shift of treatment from dapsone monotherapy to multidrug therapy regimen has given a new hope. The multidrug therapy coupled with the newer vaccines promise better results to prevent further transmission. Globally and locally the efforts to decrease the burden of leprosy by using different strategies has resulted in elimination of leprosy. But there is still a long way to go to make world free of this dreaded disease.

**Keywords:** leprosy, prevention, vaccine, disability, multidrug therapy, rehabilitation


**4.2 Perception of implementation of National health policy**

Findings from this current study revealed that respondents are influenced in accessing health care for their wards even when they are insured as they perceived the implementation of the National Health Policy to be ineffective concerning poorquality health service for the insured. This finding is similar to Bruce et al. [19] study results on "The perceptions and experiences of health care providers and clients in two districts in Ghana" which showed that insured clients are not satisfied with the healthcare they received and perceived that they were given poorer quality services and tend to wait longer as compared to those making Out of Pocket Payment (OOP). The present study also revealed that the implementation of the National Health Policy is ineffective as respondents perceived that it does not cover major specialized services and treatment for children with CP. This study finding is in contrast to Dalinjog and Laar's [20] study on "The effectiveness of the National Health Policy in Ghana" which found that both insured and uninsured respondents had positive perceptions and were satisfied with the care provided.


2. Background theory

the earth at certain frequency ranges. Data are recorded as time series in two-way time (TWT) manner which after processing can be converted into depth domain by adding the velocity model during processing. Figure 1 shows the georadar instru-

Due to the ability of detecting shallow object with high resolution, georadar has been applied in many fields with various objectives. Georadar is able to distinguish two different objects based on different electrical properties; hence, georadar are commonly used in various field such as environment study, mining, ground water, ancient artifact, and others. Not only able to detect the electrical properties contrast of material, but also georadar is able to detect the subsurface structure like faults and folds. Hence, the application of georadar for detecting the subsurface structures and monitoring of active faults for mitigation purposes are promising, especially for unstable area in the urban/suburban area with high population where other active

The exact location of an active fault in urban area is very important to be known

Lembang fault is an example for active fault across urban area with high population density in Bandung, Indonesia. In this area, there are not less than 8 million people leaving around the Lembang fault. The length of this fault itself is about 29 km from east to west part of Bandung [3] as illustrated in Figure 2. Because of the compression system in this area, it is predicted that a huge accumulated energy is concentrated in this fault and potentially can be released any time as an earthquake. The earthquake then is predicted also which leads to trigger the local land-

Due to some reasons such as soil stability and environmental concern, techniques such as seismic refraction and seismic reflection that use dynamite explosion as a source, are not allowed. Hence the use of georadar technique for identifying

for the mitigation purposes. Hence, the potential landslide due to the unstable structure of this area can be warned early to avoid serious hazard or disaster. Many techniques have been used to monitor the stability and mitigate the potential landslide in the area around the active fault which is across the urban area. Nondestructive geophysical methods such as electrical method and electromagnetic method are commonly selected for the investigation and evaluation of the subsurface structure this area. Geo-penetrating radar (GPR) or georadar method is also a common geophysical method that is applied to understand the bedding subsurface and

ment and example of recorded data.

structure in the high-risk area in such condition.

(a) Georadar instrument [2], (b) example of recorded subsurface data.

source is prohibited.

Earth Crust

slide in this area.

Figure 1.

48

### 2.1 Georadar wave propagation

Georadar technique is developed based on electromagnetic wave propagation theory. In one dimension (1D), the propagation of electromagnetic wave in z-direction is explained by Maxwell equation:

$$\frac{\partial^2 E}{\partial \mathbf{z}^2} = \mu \varepsilon \frac{\partial^2 E}{\partial t^2} \tag{1}$$

The propagation of the electromagnetic wave is perpendicular to the electrical field (E) and magnetic field (H) and controlled by the velocity and attenuation of medium. The properties of medium are also related to the mineral composition and also water saturation of medium. The velocity of wave propagation in the medium depends on the velocity of electromagnetic wave in the vacuum (c = 0.3 m/ns), relative dielectric constant (εr), and relative magnetic permeability (μr ¼ 1 for nonmagnetic material):

$$V\_m = c / \left\{ (\varepsilon\_r \mu\_r/2) \left[ \left( \mathbf{1} + P^2 \right) + \mathbf{1} \right] \right\}^{1/2} \tag{2}$$

where P ¼ σ=ωε is an absorption factor and σ is conductivity of medium, ϖ ¼ 2πf, where f is frequency and ε ¼ εrεo is vacuum permittivity (8.854 � 10�12 F/m). For the material with low loss, P� 0, the velocity of georadar is

$$V\_m = c/\sqrt{\varepsilon\_r} = 0.3/\sqrt{\varepsilon\_r}$$

Recording of georadar data is based on the reflection responses of dielectric contrast of medium. If dielectric contrast in the interface between different layers is strong, the reflectors have a strong amplitude in the georadargram. The strength of reflection (reflection coefficient R) is determined by the contrast of velocity and relative dielectric of medium at the boundary. The number of reflected energy is proportional to R:

$$R = \frac{(V\_1 - V\_2)}{(V\_1 + V\_2)} \text{ or } R = \frac{\sqrt{\varepsilon\_2} - \sqrt{\varepsilon\_1}}{\sqrt{\varepsilon\_2} - \sqrt{\varepsilon\_1}} \tag{3}$$

ε ∗ ¼ ε 0 þ i ε 00

is static or DC conductivity, while the complex conductivity is

where ω is angular frequency.

using a simple relation, V ¼ c= ffiffiffiffi

predicted or vice versa.

tomography (Figure 3).

coefficient [5].

51

2.3 Data processing

constant and porosity (ϕ) is defined as

DOI: http://dx.doi.org/10.5772/intechopen.85397

σ ∗ ¼ σ 0 þ iσ 00

εr

2.2 Configuration and resolution of georadar survey

velocity in the air, the velocity of georadar in the medium is defined as

þ σs=ωεo

where ε\* is a complex permittivity, ε" is an imaginary part of permittivity, and σs

Identification of Active Faults in Landslide-Prone Regions Using Ground-Penetrating Radar…

In the porous medium material where water is a saturant, the bulk dielectric

where εm and εw are dielectric constant of matrix and water, respectively. By

Eq. (9) shows that if velocity can be extracted, then porosity of medium can be

Effectiveness and recoverable of georadar survey is determined by the configuration of the survey. At least there are two types of acquisition: monostatic mode and bistatic mode. In the monostatic mode, one antenna is used as transmitter

The vertical resolution of georadar is defined by its frequency or wavelength. Each antenna of georadar is designed for certain frequency range, where the peak energy will be associated in the peak frequency of the signal. Hence the vertical resolution georadar signal is determined by wavelength divide by four (λ/4). Meanwhile, the horizontal resolution of georadar is controlled mainly by the number of traces/s (or traces/m), the beam width, the radar cross section of the reflector, and the depth where target is located [4]. The conical beam of georadar signal itself is inversely proportional to the square root of attenuation coefficient (√α). It means that the horizontal resolution is better in the medium with high attenuation

Data processing in radargram depends on the objectives; there is no standard processing workflow. However, usually the processing data is done to gain the signal which is attenuated during propagation, removing some noise by filtering, deconvolution, and diffraction reduction through migration process. For certain purposes, sometimes the conversion from time domain needs to be done to get the

depth domain; in this case the velocity model is needed.

and receiver simultaneously. While in the bistatic mode, the receiver and transmitter are separated using different antenna. Based on the target itself, the configuration of data acquisition can be performed using different ways: radar reflection profiling, wide-angle reflection and reflection (WARR) and common midpoint (CMP) sounding, and transillumination or

� � (6)

¼ jωεoε ∗ (7)

εr ¼ ð Þ 1 � ϕ εm þ ϕεw (8)

p , for low loss material where c is georadar wave

V ¼ c=½ � ð Þ 1 � ϕ εm þ ϕεw (9)

where v1 and v2 are wave velocity of georadar at first and second layers and ε1 and ε2 are relative dielectric constant at first and second layers, respectively.

The energy loss during wave propagation is determined by some factors: antenna, transmission between air and soil, reduction due to the configuration or distance between transmitter and receiver, attenuation, and diffraction due to the sharp object. The energy reduction due to the wave propagation between transmitter and receiver is proportional to 1/r2 , where the r is distance measured between source/antenna and receiver (another antenna), attenuation factor which defend on the dielectric properties of medium, and its magnetic and electrical field itself in the medium. Amplitude will be reduced in the depth of penetration due to the attenuation which is proportional to 1/e (about 37%) of initial energy which also called as skin depth. The skin depth depends on soil resistivity. The ratio of two different amplitudes is formulated as

$$E\_o/E\_x = \exp\left(-a\mathbf{x}\right) \tag{4}$$

where α is attenuation coefficient

$$a = \alpha \left\{ \left( \frac{\mu \varepsilon}{2} \right) \left[ \left( \mathbf{1} + \frac{\sigma^2}{\alpha^2 \varepsilon^2} \right)^{1/2} - \mathbf{1} \right] \right\}^{1/2} \tag{5}$$

Loss factor (P) = σ/ωϵ = tan D and skin depth is defined as

$$\delta = \mathbf{1}/a$$

If D < <1, δ ¼ ð Þ 2=σ ð Þ ε=μ 1=2 , the skin depth is formulated:

$$\delta = (\mathbf{5.31\sqrt{\varepsilon\_r}})/\sigma$$

where σ is an electrical conductivity (mS/m).

In the saturated porous medium, the loss energy is proportional to the conductivity and invers proportionally to the relative dielectric constant and frequency. The conductivity and relative dielectric constant is dominated by fluid saturant compared to the matrix itself. The bulk of relative dielectric constant (εr) is roughly equal to porosity and relative dielectric constant of fluid (εr). Due to the fluid/saturant is more conductive, the attenuation becomes higher. The geological material mostly have a relative dielectrical constant is about 3–30, and hence the georadar wave velocity is about 0.06–0.175 m/ns, while the air velocity is 299.8 mm/ns.

The relationship between dielectric, permittivity, and conductivity of medium is governed by

Identification of Active Faults in Landslide-Prone Regions Using Ground-Penetrating Radar… DOI: http://dx.doi.org/10.5772/intechopen.85397

$$
\boldsymbol{\varepsilon}^\* = \boldsymbol{\varepsilon}^\prime + \dot{\boldsymbol{\varepsilon}} \left( \boldsymbol{\varepsilon}^\prime + \sigma\_\circ / \rho \mathbf{e}\_\sigma \right) \tag{6}
$$

where ε\* is a complex permittivity, ε" is an imaginary part of permittivity, and σs is static or DC conductivity, while the complex conductivity is

$$
\sigma^\* = \sigma' + i\sigma'' = ja\epsilon\_o\varepsilon^\* \tag{7}
$$

where ω is angular frequency.

Vm ¼ c= ffiffiffiffi

R ¼ ð Þ V1 � V2 ð Þ V1 þ V2

proportional to R:

Earth Crust

ter and receiver is proportional to 1/r2

where α is attenuation coefficient

If D < <1, δ ¼ ð Þ 2=σ ð Þ ε=μ

299.8 mm/ns.

governed by

50

α ¼ ω με

2 � �

Loss factor (P) = σ/ωϵ = tan D and skin depth is defined as

1=2

where σ is an electrical conductivity (mS/m).

amplitudes is formulated as

εr p ¼ 0:3= ffiffiffiffi

Recording of georadar data is based on the reflection responses of dielectric contrast of medium. If dielectric contrast in the interface between different layers is strong, the reflectors have a strong amplitude in the georadargram. The strength of reflection (reflection coefficient R) is determined by the contrast of velocity and relative dielectric of medium at the boundary. The number of reflected energy is

or R ¼

where v1 and v2 are wave velocity of georadar at first and second layers and ε1

source/antenna and receiver (another antenna), attenuation factor which defend on the dielectric properties of medium, and its magnetic and electrical field itself in the medium. Amplitude will be reduced in the depth of penetration due to the attenuation which is proportional to 1/e (about 37%) of initial energy which also called as skin depth. The skin depth depends on soil resistivity. The ratio of two different

> 1 þ σ2 ω2ε2 � �1=2

δ ¼ 1=α

δ ¼ 5:31 ffiffiffiffi

In the saturated porous medium, the loss energy is proportional to the conductivity and invers proportionally to the relative dielectric constant and frequency. The conductivity and relative dielectric constant is dominated by fluid saturant compared to the matrix itself. The bulk of relative dielectric constant (εr) is roughly equal to porosity and relative dielectric constant of fluid (εr). Due to the fluid/saturant is more conductive, the attenuation becomes higher. The geological material mostly have a relative dielectrical constant is about 3–30, and hence the georadar wave velocity is about 0.06–0.175 m/ns, while the air velocity is

, the skin depth is formulated:

εr p ð Þ=σ

The relationship between dielectric, permittivity, and conductivity of medium is

( ) " # 1=2

and ε2 are relative dielectric constant at first and second layers, respectively. The energy loss during wave propagation is determined by some factors: antenna, transmission between air and soil, reduction due to the configuration or distance between transmitter and receiver, attenuation, and diffraction due to the sharp object. The energy reduction due to the wave propagation between transmit-

εr p

ffiffiffiffi ε2 p � ffiffiffiffi ε1 p

ffiffiffiffi ε2 p � ffiffiffiffi ε1

p (3)

(5)

, where the r is distance measured between

Eo=Ex ¼ exp ð Þ �αx (4)

� 1

In the porous medium material where water is a saturant, the bulk dielectric constant and porosity (ϕ) is defined as

$$
\varepsilon\_r = (\mathbf{1} - \phi)\varepsilon\_m + \phi\varepsilon\_w \tag{8}
$$

where εm and εw are dielectric constant of matrix and water, respectively. By using a simple relation, V ¼ c= ffiffiffiffi εr p , for low loss material where c is georadar wave velocity in the air, the velocity of georadar in the medium is defined as

$$\mathbf{V} = \mathbf{c} / [(\mathbf{1} - \phi)\varepsilon\_m + \phi \varepsilon\_w] \tag{9}$$

Eq. (9) shows that if velocity can be extracted, then porosity of medium can be predicted or vice versa.

#### 2.2 Configuration and resolution of georadar survey

Effectiveness and recoverable of georadar survey is determined by the configuration of the survey. At least there are two types of acquisition: monostatic mode and bistatic mode. In the monostatic mode, one antenna is used as transmitter and receiver simultaneously. While in the bistatic mode, the receiver and transmitter are separated using different antenna. Based on the target itself, the configuration of data acquisition can be performed using different ways: radar reflection profiling, wide-angle reflection and reflection (WARR) and common midpoint (CMP) sounding, and transillumination or tomography (Figure 3).

The vertical resolution of georadar is defined by its frequency or wavelength. Each antenna of georadar is designed for certain frequency range, where the peak energy will be associated in the peak frequency of the signal. Hence the vertical resolution georadar signal is determined by wavelength divide by four (λ/4). Meanwhile, the horizontal resolution of georadar is controlled mainly by the number of traces/s (or traces/m), the beam width, the radar cross section of the reflector, and the depth where target is located [4]. The conical beam of georadar signal itself is inversely proportional to the square root of attenuation coefficient (√α). It means that the horizontal resolution is better in the medium with high attenuation coefficient [5].

#### 2.3 Data processing

Data processing in radargram depends on the objectives; there is no standard processing workflow. However, usually the processing data is done to gain the signal which is attenuated during propagation, removing some noise by filtering, deconvolution, and diffraction reduction through migration process. For certain purposes, sometimes the conversion from time domain needs to be done to get the depth domain; in this case the velocity model is needed.

where t is travel time, A is attenuation factor, B is spherical divergence factor,

In the implementation on processing, programmed gain control (PGC) and automated gain control (AGC) are commonly used. In the PGC, the gain function is estimated by interpolating the amplitude at certain window sample. While in the AGC, the gain function is generated by taking root mean square (RMS) on each amplitude at certain window. The gain function g(t) is interpolated in the central of the selected window. The window length selection affects the reflector strength in the result. If the window length is too wide, the signal from deeper part will gain less, and if selected window is too small, all the reflection will be gained strongly; in this case it is difficult to distinguish strong reflector from others because all reflector

Identification of Active Faults in Landslide-Prone Regions Using Ground-Penetrating Radar…

The velocity analysis needs to be conducted to know the value of velocity (velocity model); hence, the true depth and slope can be estimated. Direct measurement of medium velocity can be done from wellbore or indirectly through velocity analysis during normal moveout (NMO) process. The NMO process is

> ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi x 2 � �2 þ h2

> > ð Þþ 0 x2 V2

V (11)

=V2

ð Þ¼ 0 4h2

q

4h2 V2 , if T2

V2 þ

ð Þ¼ x T2

where V is velocity obtained from relation of reflection time at zero offset and

Geological of Bandung area is still young and renewed because of volcanic activities around Bandung area. Based on previous study, there is a Lembang fault in Bandung area which occurred from tectonic process. This fault located in the

and C is gain constant.

Figure 4.

will be gained strongly.

illustrated in Figure 4:

offset and distance/offset.

53

The function of NMO is describes as follows:

Schematic of transmitter and receiver related to the NMO process.

DOI: http://dx.doi.org/10.5772/intechopen.85397

4 x2 4 þ h2 � �

T2 ¼

3. Acquisition and processing data

T ¼ 2S V ¼ 2

V2 ¼ x2

Then T2

Figure 3.

(A) Sounding WARR dan, (B) sounding CMP, (C) graph of time-offset (T-X) with NMO, (D) graph of relationship T2–X2 [3].

Gain is performed to amplify the amplitude decay due to the distance of propagation. Factors affecting the amplitude decay are attenuation and spherical divergence propagation. Gain is performed by applying a gain function g(t):

$$\text{Gain} \,\left(\text{dB}\right) = \text{A.t} + \text{B.20} \,\log\left(\text{t}\right) + \text{C} \tag{10}$$

Identification of Active Faults in Landslide-Prone Regions Using Ground-Penetrating Radar… DOI: http://dx.doi.org/10.5772/intechopen.85397

Figure 4.

Schematic of transmitter and receiver related to the NMO process.

where t is travel time, A is attenuation factor, B is spherical divergence factor, and C is gain constant.

In the implementation on processing, programmed gain control (PGC) and automated gain control (AGC) are commonly used. In the PGC, the gain function is estimated by interpolating the amplitude at certain window sample. While in the AGC, the gain function is generated by taking root mean square (RMS) on each amplitude at certain window. The gain function g(t) is interpolated in the central of the selected window. The window length selection affects the reflector strength in the result. If the window length is too wide, the signal from deeper part will gain less, and if selected window is too small, all the reflection will be gained strongly; in this case it is difficult to distinguish strong reflector from others because all reflector will be gained strongly.

The velocity analysis needs to be conducted to know the value of velocity (velocity model); hence, the true depth and slope can be estimated. Direct measurement of medium velocity can be done from wellbore or indirectly through velocity analysis during normal moveout (NMO) process. The NMO process is illustrated in Figure 4:

The function of NMO is describes as follows:

$$T = \frac{2S}{V} = \frac{2\sqrt{\left(\frac{\mathbf{x}}{2}\right)^2 + h^2}}{V} \tag{11}$$

$$T^2 = \frac{4\left(\frac{\mathbf{x}^2}{4} + h^2\right)}{V^2} = \frac{\mathbf{x}^2}{V^2} + \frac{4h^2}{V^2}, \text{if } \mathbf{T}^2(\mathbf{0}) = 4\mathbf{h}^2/\mathbf{V}^2$$

$$\text{Then } T^2(\mathbf{x}) = T^2(\mathbf{0}) + \frac{\mathbf{x}^2}{V^2}$$

where V is velocity obtained from relation of reflection time at zero offset and offset and distance/offset.

### 3. Acquisition and processing data

Geological of Bandung area is still young and renewed because of volcanic activities around Bandung area. Based on previous study, there is a Lembang fault in Bandung area which occurred from tectonic process. This fault located in the

Gain is performed to amplify the amplitude decay due to the distance of propagation. Factors affecting the amplitude decay are attenuation and spherical diver-

(A) Sounding WARR dan, (B) sounding CMP, (C) graph of time-offset (T-X) with NMO, (D) graph of

Gain dB ð Þ¼ A:t þ B:20 log tð Þþ C (10)

gence propagation. Gain is performed by applying a gain function g(t):

Figure 3.

Earth Crust

52

relationship T2–X2 [3].

southern part of Lembang and crossing Cisarua from east to west of Manglayang mountain. Throw of this fault is varying up to 450 m in Pulasari near to the target area. The Lembang fault was created during the Pleistosen era (about 500,000 years ago) [6].

In the end of Miocene, series of mountains and folds are created in the northern part and in the southern part which become series of volcanos. In the breaking time of Pliocene era, there is no activity of volcanoes and sedimentation, and in the end of Pliocene era, series of mountains were created, and sediments in the northern part were folded and shifted into northern part of Bandung. Materials as a result of volcano eruption activities are distributed into southern part of Bandung.

domain into depth domain in the profile. In general, the velocity is quite high because the lithology is dominated by tuff, andesite, and breccia volcanic.

Velocity model extracted from hyperbole fitting curve during velocity analysis.

Depth (m) Velocity (m/μs) 15.63 196.17 17.16 186.37 22.25 180.69

Identification of Active Faults in Landslide-Prone Regions Using Ground-Penetrating Radar…

Out of several profiles which were studied, profile 03 displayed the large fault in the radargram which is associated with a main Lembang fault. In the other profiles, there are some small fault systems. Based on the velocity analysis, the structure of Lembang fault is a conductive area where the velocity decreases with depth. Profile in Figure 6 which is taken perpendicular to the fault shows a normal fault system. The foot wall is located in the northern part and hanging wall in the southern part. The position of foot wall part is lower about 7–8 m compared to the hanging wall part. The structure of this area consists of basement which is indicated by a free reflection area and sediment bedding in the horizontal layer. Above the foot wall

In Figure 6, the top of basement formation is interpreted as the blue line indicates a normal fault. The folded reflection can be resulted as post fault due to the compression from the northern part; the horizontal bedding is folded as small anticline. Cracking in the shoulder of road around this profile indicates that the fault reaches the surface. Those crack lies in the west–east direction where the northern part is lower than southern part. Previous study mentioned that this active

4. Result and discussion

DOI: http://dx.doi.org/10.5772/intechopen.85397

Table 2.

Figure 6.

55

Cross section taken perpendicular to the fault.

part, there is a pattern of unconformity.

To detect the existence of Lembang fault, a georadar survey was conducted in this area. Sketch of data gathering in this area is shown in Figure 5. The data collection was conducted using common-offset method with 25 and 50 MHz antenna. Most of the profile was selected perpendicular to the fault.

All the data are processed using Seismic Unix (SU) software by performing the scaling on the time sampling rate from nanosecond to millisecond (ms), frequency from megahertz to hertz and velocity from m/ns to m/μs. The details of conversion factor are shown in Table 1.

The processing data includes filtering using band-pass filter (10, 20, 30, 50) MHz for antenna 25 MHz and (10, 30, 70, 100) MHz for 50 Hz, AGC, and velocity analysis based on hyperbole fitting curve. The velocity obtained from hyperbole fitting curve is shown in Table 2. This velocity model was used to convert time


**Abstract**

Impact of porosity, rotation and finite ion Larmor radius (FLR) corrections on thermal instability of immeasurable homogeneous plasma has been discovered incorporating the effects of radiative heat-loss function and thermal conductivity. The general dispersion relation is carried out with the help of the normal mode analysis scheme taking the suitable linearized perturbation equations of the difficulty. This general dispersion relations is further reduces for rotation axis parallel and perpendicular to the magnetic field. Thermal instability criterion establishes the stability of the medium. Mathematical calculations have been performed to represent the impact of different limitations on the growth rate of thermal instability. It is found that rotation, FLR corrections and medium porosity stabilize the growth rate of the medium in the transverse mode of propagation. Our outcome of the problem explains that the rotation, porosity and FLR corrections affect the dens molecular clouds arrangement and star configuration in interstellar medium.

**Keywords:** Thermal instability, Rotation, FLR Correction, Radiative heat-loss functions, ISM


**Abstract**

Salients were formed in the lee of two artificial reefs (submerged breakwaters) constructed on Kimigahama Beach in Chiba Prefecture, Japan, owing to the wavesheltering effect of the reefs, and then, a significant amount of fine sand was transported inland from the salients by wind action. In this study, not only shoreline changes after the installation of the two artificial reefs but also beach changes caused by windblown sand were predicted using a model, in which the BG model (a model for predicting three-dimensional beach changes due to waves based on Bagnold's concept) is combined with a cellular automaton method. Reproduction calculation was carried out on the basis of field data. Beach changes after the artificial reefs were removed were also predicted and the effect of beach nourishment was investigated. It was concluded that landward sand transport by wind is accelerated when wavesheltering structures such as an artificial reef are constructed on a coast composed of fine sand, and such an effect can be successfully predicted by using the present model.

**Keywords:** artificial reef, windblown sand, predictive model, BG model, cellular automaton method, Kimigahama Beach


**4.1 Ionic liquids**

*Ionic liquids*: 1-butyl-3-methyl-imidazolium hexafluoro phosphate [bmim]PF6, 1-butyl-3 methyl-imidazolium tetrafluoro-borate [bmim]BF4, tributyl tetradecyl phosphonium dodecilbenzol sulfonate (Cyphos-201), trihexil tetradecyl phosphonium bis- (2,2,4 trimetilpentil)-phosphate (Cyphos-104), tetradecyl phosphonium trihexil decanoate (Cyphos-105) trihexyl tetradecyl phosphonium hexafluoride, phosphate (Cyphos-110) (IoLiTec GmbH, Germany)

*Reaction mixture composition*: Under the pre-investigations, the reaction mixture was the follow: 6.36 mmol of oleic acid, 36.95 mmol of isoamyl alcohol, 304.35 mmol n-hexane and 50 mg Novozym 435 lipase. In the course of the main experiment: 1.23 mmol of ionic liquid, 0.16 mmol oleic acid, 1.41 mmol isoamyl-alcohol were used. The reaction mixtures were shaken with an intensity of 150 rpm at 40, 50 and 60 º C temperatures for 4 hours.

#### **4.2 Effect of ionic liquid**

As it well known ionic liquids are not only green solvents, they can have catalytic effect. Our aim was to investigate separately the enzyme stabilization effect, therefore preliminary experiments were necessary. Through these the most important investigated criterion was to verify if the ionic liquid itself had catalytic effect for the reaction without enzyme. Basic criterion was to be work in a two-phase reaction, where separation is easier, since the application of a new solvent can be avoid (Eckstein et al., 2004). Two of the investigated

Kinetic model for description of the enzymatic esterification of oleic acid and i-amyl alcohol was – according to our best knowledge – elaborated and presented in the first time in literature. The model is based on the ping-pong bi-bi mechanism and not only product, but substrate inhibition is taken into account, as well. The model fitted well to the experimental data (checked by r2 values), though the measurements covered an extremely wide

Ionic liquids can be suitable media for biocatalytic synthesis because of their enzyme stabilization effect, reusability and negligible vapour pressure (Yang & Pan, 2005). Many enzymes, especially lipases showed higher activity and greater selectivity in ionic liquids than in organic solvents (Jain et al., 2006). The stability of *Candida antarctica* lipase B (CALB) in ionic liquid was found to be higher than in organic solvent (Romero et al., 2005). The main advantages of ionic liquid + enzyme system are milder, lower reaction temperature comparing with conventional chemical synthesis, it needs less energy investment, can be better-controlled, attended with less side-reaction, furthermore the product more readily separable. In this work the purpose was to find a utilization of fusel oil where biolubricants

In organic solvents low conversions were achieved, therefore it became necessary to develop a better method, which is energy efficient, able to achieve higher conversion, furthermore environmental friendly, however waste materials may be as natural substrates. Our aim is to optimize the parameters of production, enhance the yield improving the advantages of

*Ionic liquids*: 1-butyl-3-methyl-imidazolium hexafluoro phosphate [bmim]PF6, 1-butyl-3 methyl-imidazolium tetrafluoro-borate [bmim]BF4, tributyl tetradecyl phosphonium dodecilbenzol sulfonate (Cyphos-201), trihexil tetradecyl phosphonium bis- (2,2,4 trimetilpentil)-phosphate (Cyphos-104), tetradecyl phosphonium trihexil decanoate (Cyphos-105) trihexyl tetradecyl phosphonium hexafluoride, phosphate (Cyphos-110)

*Reaction mixture composition*: Under the pre-investigations, the reaction mixture was the follow: 6.36 mmol of oleic acid, 36.95 mmol of isoamyl alcohol, 304.35 mmol n-hexane and 50 mg Novozym 435 lipase. In the course of the main experiment: 1.23 mmol of ionic liquid, 0.16 mmol oleic acid, 1.41 mmol isoamyl-alcohol were used. The reaction mixtures were

As it well known ionic liquids are not only green solvents, they can have catalytic effect. Our aim was to investigate separately the enzyme stabilization effect, therefore preliminary experiments were necessary. Through these the most important investigated criterion was to verify if the ionic liquid itself had catalytic effect for the reaction without enzyme. Basic criterion was to be work in a two-phase reaction, where separation is easier, since the application of a new solvent can be avoid (Eckstein et al., 2004). Two of the investigated

shaken with an intensity of 150 rpm at 40, 50 and 60 º C temperatures for 4 hours.

concentration range.

**4. Reaction in ionic liquid**

can be manufactured in ionic liquid.

enzyme+ionic liquid system.

(IoLiTec GmbH, Germany)

**4.2 Effect of ionic liquid**

**4.1 Ionic liquids**

ionic liquids (Cyphos-105 and Cyphos-110) were mixed with the substrates, so they were not investigated further. Henceforth the reactions were carried out at 50 °C, the ester yield was followed by GC and the decreasing oleic acid concentration using titrimetry. The percentage esterification was calculated from the values obtained for the blank and the test samples. The further phosphonium-type ionic liquids, Cyphos-201 and Cyphos-104 without the presence of enzyme greatly catalyze the process as it shown on Fig. 7.

Fig. 7. Oleate ester concentration in case of using different phosphonium-type ionic liquids (reaction time: 180 min)

For imidazolium-cation containing ionic liquids literary data show that these types of ionic liquids are the most suitable for esterification, transesterification reactions (Moniruzzaman at al., 2010). Both investigated imidazolium-type ionic liquids were successfully applied in earlier experiments, where natural aroma esters production was the aim. In case of [bmim]BF4 there were no significant differences in the detected oleate concentration if enzyme was added or not. For [bmim]PF6 - without the presence of the enzyme only negligible product formation was observed, in the presence of enzyme, higher concentrations were achieved than in the experiments where n-hexane was used as solvent.

Therefore for further investigations this ionic liquid was chosen. In case of ionic liquids for water solubility cations are responsible. Comparing the same cation having [bmim]BF4 and [bmim]PF6 shows that while the first not miscible with water, the later has an unlimited solubility in water. Thus, the hydrophilic [bmim]BF4 ionic liquid often distracts the absorbed water layer from the surface of the enzyme which should be necessary for the active conformation. Therefore the enzyme is deactivated (van Rantwijk & Sheldon, 2007). Further advance that in case of using [bmim]PF6 side-reactions were not observed.

#### **4.3 Acid/alcohol molar ratio**

The optimal parameters of the batch production were determinated using experimental design software application. In doing so Statistica 8.0 program was applied. Based on earlier studies substrate molar ratio, amount of enzyme and ionic liquid were chosen as key factors. Each factor was prepared in two levels: -1 for low level and +1 for high level.

Time [h]) 0 5 10 15 20 25 30

The yield-time functions in all cases show the saturation curve. Increasing the temperature equilibrium yield was not changed, but shorter time was necessary to achieve it. As it shown neither at 80 °C became the enzyme deactivation significant, but increasing up from 70 °C

Our investigations have proven that an ester type biolubricant could be prepared from fusel oils and oleic acid by lipase enzyme in solvent-free system. Compared to the product obtained by acid catalysis, in the biolubricant there was no trace of oleic acid since complete conversion was achieved by continuous water removal by pervaporation. Our product was then tested in an acute toxicological procedure by zebrafishes, which has verified the assumption: the biolubricant is not toxic for the living water, so it is considered as an

The tribological study has shown that the features of the biolubricant are similar to the DB 32 type synthetic reference lubricating oil, so it can be applied as a low viscosity lubricant, suitable even for special publication processes, where lubricant loss may accur. Although the biological degradation of the product has not been studied, it was manufactured from initial compounds having biological origin (oleic acid from plant oils and alcohols from a by-product in bioalkohol production), thus it is considered as a completely environmental-

The kinetic model containing the parameters determined can be used in the particular enzymatic esterification reaction for calculations of the optimal conditions of various aspects, like highest yield, lowest acid residue, lowest amount of enzyme, shortest reaction time…etc. Moreover we are planning to apply the model for bioreactor design to realise

Our work has showenn that an ester type biolubricant could be prepared from isoamylalcohol and oleic acid by lipase enzyme in ionic liquid two phase system. Compared to the product obtained in solvent free system, higher conversion in shorter time was achieved. Despite the lack of water removal in the biolubricant there was no trace of oleic

Fig. 9. Influence of reaction temperature on the synthesis of isoamyl-oleate

did not shorten the reaction time till achieving the equilibrium.

continuous enzymatic i-amyl oleate synthesis by lipase.

70°C 60°C 80°C 133

Yield [%]

**5. Conclusions**

friend product.

environmental safe product.

0

20

40

60

80

100

120

Concrete values were applied in a design matrix. It is evident that increasing reaction temperature enhances the reaction rate, that is way that its affect will be investigated later separately.

During the experiments different, software-defined combinations of the previously selected values of experimental parameters were investigated. Other parameters were fixed: temperature 50 °C, 150 rpm shaking intensity, 5 hours reaction time. Water content of the reaction mixture was also followed as an important parameter of esterification reactions which may shift the equilibrium, but there was not detectable concentration change using Carl-Fischer titration. The aim was to find the optimal parameter values of the isoamyloleate production. The results are shown on Fig. 8.

As it shown, increasing amount of ionic liquid results in higher oleate yield, which gives evidence for the advantageous enzyme stabilization effect. Complex investigation of the three chosen key factors shows that the highest ester conversion was obtained in the case of application the highest acid/alcohol molar ratio, amount of enzyme and ionic liquid. Relatively high yield was obtained also around medium values, around the center points.

Fig. 8. Influence of the acid/alcohol molar ratio and amount of ionic liquid on the synthesis of isoamyl oleate

There was no inhibition effect observed neither in 1:16 acid/alcohol molar ratio. As none of the point of parameters could be an optimal value, because the highest yield belonging to the highest values, therefore further investigations will necessary to find the optimal values.

#### **4.4 Effect of temperature**

In case of using conventional reaction media it is well known that increasing reaction temperature results the same yield in shorter time, but till a limit due to thermal deactivation of enzyme. Beside of the structure stabilization effect of ionic liquids the enzyme can be resist in the active conformation at higher temperatures (van Rantwijk & Sheldon, 2007). For these investigations that mixture was chosen, in which the highest oleate yield was obtained. The results are shown on Fig. 9.

Fig. 9. Influence of reaction temperature on the synthesis of isoamyl-oleate

The yield-time functions in all cases show the saturation curve. Increasing the temperature equilibrium yield was not changed, but shorter time was necessary to achieve it. As it shown neither at 80 °C became the enzyme deactivation significant, but increasing up from 70 °C did not shorten the reaction time till achieving the equilibrium.


**7. How does government policy influence the sizing of wetlands?**

Whilst there are no formal policies requiring wetlands there are policies that promote stormwater quality treatment to meet mandatory sediment and nutrient concentrations defined in statutory policies. The Environmental Protection Agency (EPA) has created the State Environment Protection Policies (SEPP), and of relevance to wetland policy is the SEPP Waters of Victoria [8]. The SEPP Waters of Victoria outline the required concentrations of sediment and nutrients in waterways and larger receiving bodies, such as Port Phillip Bay and Western Port, for waters to be considered healthy. In addition to the main policy, there are various Schedules that provide unique requirements for specific catchments, e.g., SEPP Schedule F6 relates to the water quality requirements of waters for Port Phillip Bay, SEPP Schedule F7 relates specific requirements of the Yarra catchment, etc. These policies are statutory under Section 16 of the Environment Protection Act 1970 [8]. The information provided in the SEPPs indicates what the receiving water's concentrations of pollutants should be [45]. Whilst this information is useful for providing guidelines for testing it provides little guidance on what stormwater quality treatment is required for new urban developments to maintain these concentrations in the receiving bodies [45]. To try and bridge this gap, the EPA and a panel of stakeholders and experts, which included the Department of Sustainability and Environment, Melbourne Water, Municipal Association of Victoria and local government, were engaged to develop the Best Practice Environmental Management (BPEM) guidelines, which provides a pragmatic methodology for maintaining the concentrations of sediment and nutrients listed in the SEPPs [8, 9].

Rather than produce guidelines that have a focus on concentrations, the BPEM guidelines promote performance objectives that utilize a sediment and nutrient load reduction procedure, and if followed, should maintain the concentrations listed in the SEPPs [9, 45]. **Table 2** defines the required load reductions by SWQT assets to meet the BPEM objectives and subsequently meet the SEPP (Waters of Victoria) concentration requirements.

The reduction loads were determined by the Cooperative Research Centre for Catchment Hydrology, in their research publication Best Practice Environmental Management Guidelines for Urban Stormwater. This research publication was based on data analysis within the Background Report to the Environment Protection Authority, Melbourne Water Corporation and the Department of Natural Resources and Environment, Victoria [10]. The primary intention was to create performance objectives that helped achieved the SEPP however, [10] believed that the BPEM performance objectives should be:

*2 SEPP Schedule F7—Yarra Catchment—urban waterways for the Yarra River main stream.*

*3 Litter is defined as anthropogenic material larger than five millimeters.*

#### **Table 2.**

*BPEM reduction load targets [9].*

With these considerations in mind, one of the influencing factors on the performance objectives was land-take. Mudgway [10] found that an asset footprint of approximately 1% of the catchment was sufficient to produce reasonable reductions, e.g., TSS (40– 80%) and T.P (35–45%). Hence the performance objectives were created in an attempt to satisfy the SEPP and the ideals above and not necessarily to prescribe treatment for certain flow frequencies. SEPP and BPM have an influence on the sizing of SWQT assets however it is indirectly and not through explicit statements. Most wetlands are sized for the 1 in 3 months flow, however, this appears to be more of a rule of thumb, which can be enforced by local authorities such as Melbourne Water, rather than a statutory requirement [17]. The 1 in 3-month flow is nominally sized flow frequency which has generally been utilized to satisfy the BPEM performance objectives (retention of the typical annual load: TSS = 80%, TP = 40%, TN = 45%) [9]. The primary objective of wetland sizing is to meet the BPEM performance objectives, and it just SQ happens that the 1 in 3-month flow meets this objective.

Despite the fact the BPEM performance targets are the primary drivers for sizing wetlands, local authorities such as Melbourne Water may enforce that wetland be sized for 1 in 3-month flows. This may not necessarily be due to treatment meeting the SEPP concentrations but rather for maintenance reasons, e.g., plant protection [17]. The authority with which Melbourne Water may influence the sizing of the wetland is

*Understanding the Role of Constructed Wetlands in Stormwater Management DOI: http://dx.doi.org/10.5772/intechopen.102912*

somewhat convoluted as they receive their authority from the Water Act 1989, and the Environment Protection Act 1988 via the SEPP (Waters of Victoria). Through these acts and policies, Melbourne Water has the authority to dictate the design parameters of wetlands and in their most recent wetlands manual they state "All flows ≤ the peak three-month ARI event is transferred into the macrophyte zone when the EDD in the macrophyte zone is at Natural Water Level (NWL) (**Figure 2**)" [17].