Top PDF SIMULATION OF THE AIRFLOW INSIDE A HYBRID DRYER

SIMULATION OF THE AIRFLOW INSIDE A HYBRID DRYER

SIMULATION OF THE AIRFLOW INSIDE A HYBRID DRYER

Drying is an essential process used all over the world for the preservation of farm produce. It helps in reducing the water activity of the produce to a level below which deterioration doesn’t occur for a definite duration [1]. The drying process helps to achieve better product quality, longer safe storage period and reduction in post-harvest losses. The reduction in post-harvest losses ensures more food availability for growing world population [2]. Various drying methods are employed to dry different food produce. Natural sun drying is probably the oldest method to food preservation. However, it has several drawbacks, such as difficulty to control the rate of drying, insect infestation and microbial contamination. Replacing natural sun drying by artificial drying or by solar drying can significantly reduce these drawbacks and the losses caused by them [3]. Nevertheless, the drying air characteristics in solar dryers depend on ambient conditions, what can reduce the final product’s quality [4]. Artificial drying requires higher operational costs, what can be unfeasible to some applications [5]. In this context, hybrid solar dryers arise as an interesting solution [6]. The characteristics of the drying air can be controllable, improving the quality of dried products and the drying costs can be reduced, comparing with artificial drying. Many solar food dryers have been developed over the past few years, yielding varying degrees of technical performance. Fudholi et. al. [7] divide the solar dryer into four types: direct solar dryers, indirect solar dryers, mixed-mode dryers and hybrid solar dryers. The authors present a review of these types of solar dryers with aspect to the product being dried, technical and economical aspects. The technical directions in the development of solar- assisted drying systems for agricultural produce are compact collector design, high efficiency, integrated storage, and long-life drying system..
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Kinetics drying of silver banana (Musa spp.) in hybrid dryer

Kinetics drying of silver banana (Musa spp.) in hybrid dryer

ABSTRACT - The search for the reduction of production costs and for the diversification of the commercialization of agricultural products is necessary when looking to ensure autonomy and increase income for farmers. The use of solar dryers for the dry fruits production provides an excellent alternative for consideration. However, in order to introduce this technology, one must understand the drying kinetics for a given product. This paper’s purpose was to study the intermittent drying kinetics of banana in a hybrid dryer. The drying was performed in a hybrid dryer composed of a solar collector (photothermal energy), a drying chamber containing Banana-Prata cut into cylindrical and disc shapes and a power-driven exhaust system. The process occurred during four sequential days, totaling 78 h of operation and 12 h of intermittence. The effective drying period took 39 h, with a temperature and relative humidity inside the drying chamber of 43.4 °C and 45.3%, respectively, and an air speed of 1.0 m.s -1 . In the first few hours of drying, a sharp decrease in the moisture content was
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Plasma environment of Titan: a 3-D hybrid simulation study

Plasma environment of Titan: a 3-D hybrid simulation study

With its extended neutral atmosphere, Titan orbits Saturn at a distance of 20.3 Saturn radii and an orbital period of 15.95 days. Titan’s orbit is located inside Saturn’s outer magneto- sphere for average solar wind conditions, since under these circumstances the stand-off distance of the bow shock has been observed to vary typically between 23.6 and 31.5 Sa- turn radii (Ledvina et al., 2004a). The magnetosphere is po- pulated by neutral atoms and plasma from several potential sources. On the one hand, Saturn’s atmosphere and rings as well as the icy satellites can contribute to the plasma popu- lation inside the magnetosphere. On the other hand, plasma from Titan’s ionosphere and solar wind particles are also part of the plasma population. Theoretical predictions suggest that the plasma at least partially corotates with the planet (Saur et al., 2004). Due to Titan’s orbital period being con- siderable larger than Saturn’s rotational period (10.7 h), Titan is permanently embedded into a flow of magnetized plasma with a relative velocity around 120 km/s. The data that have been collected during the Voyager 1 flyby (Ness et al., 1982) as well as the magnetic field signature observed during the first Cassini encounter (Backes et al., 2005) suggest that Ti- tan does not possess a significant intrinsic magnetic field. Thus, Titan’s atmosphere and ionosphere interact directly with the Saturnian magnetospheric plasma in a similar way as Venus and Mars interact with the solar wind. However, the Titan interaction possesses several unique features.
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Molecular dynamics simulation in hybrid systems

Molecular dynamics simulation in hybrid systems

The code used in the present dissertation had the problems explained above. The if conditions present in the code were used to verify if the coordinates of a particle are still inside of the sim- ulation box and if that particle is within a distance (or radius) valid to calculate forces. The first conditions alter the coordinates of the particle in a way that if its outside the simulation box it is replaced inside the box, by applying the periodic boundary conditions (PBC). This can be seen in the listing 3.2 that shows three if conditions that compare the distance between both particles co- ordinates (rx,ry,rz) with the limits of the simulation box ( ± cellxhlf, ± cellyhlf, ± cellzhlf). The condition present in listing 3.3 is used to test if the neighbor particle is inside the cut-off radius of the particle being calculated. This condition has to exist because the update of the neighbors lists positions is only done after a few iterations, which means that while the lists are not updated, the neighbor particle can move to outside the radius. Both conditions explained before produce many conditional jumps, which can be seen in the associated assembly code. This prevents the compiler to do automatic vectorization.
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Analysis of ginger drying inside a natural convection indirect solar dryer: An experimental study

Analysis of ginger drying inside a natural convection indirect solar dryer: An experimental study

65 ˚C without and with reflector respectively. The average collector efficiency was reported to increase by 8.04% with reflector. The drying time was observed to reduce by 66.7% against open sun drying [14]. Drying kinetics of ginger rhizomes under blanched and non-blanched conditions was presented using hybrid solar dryer and the drying rate dependency on product shape, size, and drying air temperature was observed. Drying air temperature of 70˚C was reported best for better quality drying of ginger rhizome. Page model was reported best to describe the drying characteristics of ginger rhizome [15]. Thin layer solar drying of ginger was carried out for different mass flow rates of 0.06 and 0.12 kg/s with an average temperature of 54 and 44 ˚C respectively, for which Page model was reported to be most appropriate to describe the drying behaviour of ginger [7]. A solar drier was designed with evacuated tube collectors for ginger drying at different air mass flow rates varying from 4 to 5 m/s and reduced the moisture content of the product from 85.62 to 0.92%. The drier efficiency was reported to vary from 31 to 40.4 % for different air mass flow rates. Overall, the dryer was suggested to be better than other dryers in terms of quality and drying rate [3]. Drying characteristics of ginger using a mixed mode solar cabinet dryer were investigated by reducing its moisture from 621.50 to 12.19%. Solar cabinet dryer was observed to be better for ginger drying in the aspects of quality, drying time, and power requirement as compared to open sun drying. Page model was reported to be most suitable to describe the drying characteristics of ginger [16].
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Airflow simulation in a horizontal closed refrigerated display cabinet

Airflow simulation in a horizontal closed refrigerated display cabinet

With the setup used in this simulation, it is expected that the temperature was below 5°C in all the domain, where the higher temperatures would be on the bottom because this area is the one that is farthest from the inlet, despite having small entrances on the back of the equipment. In the first and seconds meshes the number of elements is low, and two completely different results can be seen. The spots where the temperature is higher is different on both cases and there are too many vortices in the first mesh, so it can be concluded that these results are not correct due to the low number of elements. In the third mesh (approximately 117,000 elements), the results start to stabilize to a certain shape (figure 4.3, mesh 3), where there is a hot spot at the bottom due to the low-velocity values in this area, but it was not yet certain that this mesh was refined enough. So, at this stage, it was used two more meshes to confirm if the third one was refined enough, or the results were still susceptible to mesh variation After analysing the results using meshes 4 and 5, it can be realized that there are still slight differences in temperatures between these two meshes and mesh 3 does not translate the same results that the last ones. Despite that, the results for the velocity values are closer, except on the back area, near the air entrances, where only on the most refined meshes it is possible to observe vortices. In this case, the velocity field remains the same, but the temperature distribution changes significantly, meaning there is still heat flux between the air inside the equipment and outside. Assuming that the flow may not be stationary yet, more simulations will be made until 120 seconds with meshes 4 and 5, instead of the 60 seconds used previously. It is also possible to verify that there is a hot spot on the bottom (figure 4.3), probably due to the fact that there is a dead zone, where the velocity is almost zero. Another aspect that can affect this phenomenon is the condition defined in the bottom wall. This condition is the same for all the walls, but this bottom boundary is very specific because it is the physical boundary between the refrigerated zone and the evaporator. Because of that, in future cases, other conditions will be studied in order to optimize the flow in this area.
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Simulating Intermediate Crack Debonding on RC Beams Strengthened with Hybrid Methods

Simulating Intermediate Crack Debonding on RC Beams Strengthened with Hybrid Methods

The externally bonded (EB) and the near-surface mounted (NSM) are two well-known methods for strengthening reinforced concrete (RC) beams. Both methods are unfortunately prone to fail prematurely through debond- ing when the amount of strengthening reinforcement provided is high. In response to this, a hybrid method that combines the EB and NSM method was introduced. The method allows the amount of reinforcement needed for EB and NSM methods to be reduced; this, in theory, should lower the inter- facial stresses, thus reducing the possibility of debonding failures. While debonding failure can be prevented, certain amounts of debonding would still occur through the interfacial crack (IC) debonding mechanism which can affect the strength and stiffness of hybrid strengthened beams even if it does not directly cause failure. This paper presents a method to simulate IC debonding of hybrid strengthened beams using the moment-rotation ap- proach. The proposed method allows a better prediction of maximum load and stiffness of the beams. The method is also less dependent on empirical formulations compared to the commonly used moment-curvature ap- proach; this allows the method to be applicable to all material and shape of hybrid strengthening reinforcement, assuming correct material models are used. The proposed method was then used to perform parametric studies; among the important findings is the length of IC debonding tend to increase when FRP sheet with higher elastic modulus is used, thus negating most of the benefit from the higher modulus.
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DEVELOPMENT OF A HYDRODYNAMIC MODEL OF A HYDROCYCLONE INCLUDING THE SIMULATION OF AIR-CORE EFFECT, USING THE FINITE VOLUME METHOD

DEVELOPMENT OF A HYDRODYNAMIC MODEL OF A HYDROCYCLONE INCLUDING THE SIMULATION OF AIR-CORE EFFECT, USING THE FINITE VOLUME METHOD

the flow inside the hydrocyclone, because if the work of the equipment is at low slurry densities, very clear for small hydrocyclones, its mechanic behavior is a consequence of the kind of liquid used as continuous phase, being water the most common liquid. This work shows the modelling and simulation of the hydrodynamic behavior of a suspension inside a hydrocyclone, including the air core effect, through the use of finite differences method. For the developing of the model, the Reynolds Stress Model (RSM) for the evaluation of turbulence, and the Volume of Fluid (VOF) to study the interaction between water and air were used. Finally, the model shows to be significant for experimental data, and for different conditions of an industrial plant.
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Mat. Res.  vol.9 número4

Mat. Res. vol.9 número4

Figure 2 shows one simulation result presenting the temperature distribution in the reactive cell, (sector D in Figure 1) where the G →฀CSPD transformation occurred. As shown in Figure 2, the body of the transformed CSPD, represented by the upper gray shaded area, occupies about 70% of the cell. Temperature values determined by the simulation are displayed in tones of gray; the higher the tempera- ture the darker the tone. The temperature distribution in Figure 2, suggests the existence of three distinct regions at the moment of the phase transformation. Region , in the core of the reactive cell, with an approximately spherical shape, corresponds to the interior of the transformed CSPD. Temperatures in this region  are relatively lower and vary from 1400 °C to 1600 °C. Region , in darker tones, concentric with the first region and corresponding to a middle zone of the CSPD. This region is associated with higher temperatures, 1800 °C to 2000 °C. Region , in lighter gray tones, also concentric with the other two regions, corresponding to the external zone of the CSPD formed at lower temperatures, 1600 °C to 1400 °C, which are comparable with those in Region .
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Investigating The Use Of Mobile Computing In Zimbabwe Polytechnics Case Of A Polytechnic In Zimbabwe

Investigating The Use Of Mobile Computing In Zimbabwe Polytechnics Case Of A Polytechnic In Zimbabwe

Zimmerman (1999) in his article titled ―Mobile Computing: Characteristics, Benefits, and the Mobile fra mework‖ defined mobile computing as ―the use of computing devices, which usually interact in some way with a centralised information system while away from the normal fixed workplace‖. He went on to say that, Mobile computing technology enables the mobile person to create, access, process, store and communicate information without being constrained to a single location. It is on the above basis that this researcher views mobile computing as embracing a host of portable technologies the can access internet using wireless fidelity (WIFI). These range from notebook computers to tablets, to smartphones and e-book readers. Such devices have brought about Mobile learning (m-Learning) in Zimbabwe Polytechnics, enabling staff and students to share academic resources, be able to research and develop applications from wherever they are. Zimmerman (1999) went on to identify mobile computing hardware, software and communications in use then. He identified hardware as palmtops, clamshells, handheld Pen Keys, pen slates, and laptops. The characteristics of such devices in terms of screen size was small, processing capability was limited and supported a few mobile applications. Over the years mobile devices have improved in such characteristics to make mobile computing easy, fast and user friendly. Great improvements also came with the associated systems software, with the modern devices now running on Android, Symbian and windows 8 mobile, as compared to then when MS DOS, Windows 3.1, Pen DOS were used. In communications Zimmerman talked of internet speeds in kilobytes per second (Kbps), while today’s communications devices have speeds of gigabytes per second (Gbps
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The comparison of the structure and microhardness of the tool steel C90 and HS 6-5-2 remelted with the electric arc

The comparison of the structure and microhardness of the tool steel C90 and HS 6-5-2 remelted with the electric arc

The tool steels consistute a very important group of materials used for the production, not only tools, but also machine ele- ments, that need to have the increased strength, for example the high-speed steels are used on the rolling bearing operating in high temperatures [1]. Modern technologies such as: laser treatment, electron treatment, CVD, PVD methods, give the possibility of forming the structure of the surface layer of steels providing the demaded properties. The economic factors direct research in using the plasma of the electric arc for shaping the surface layer of the machine elements and tools. Advantages of that method are the possibilities of receiving wider treated areas with one stream of the heat in comparison with the laser technologies or electron
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The modification process of AlSi21CuNi silumin and its effect on change of mechanical properties of the alloy

The modification process of AlSi21CuNi silumin and its effect on change of mechanical properties of the alloy

Pouring temperature belongs to very important factors in obtainment of correct results of the modification. Hypereutectoid silumins are characteristic of good castability even in temperatures close to liquidus curve, what suggests implementation of low temperature of casting. However, such method of casting creates conditions to easy coarsening of primary crystals of silicon and their non-uniform distribution on microstructure of the casting. Rate of cooling of the alloy poured into mould has also an effect on results of the modification.
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Numerical simulation of airway dimension effects on airflow patterns and odorant deposition patterns in the rat nasal cavity.

Numerical simulation of airway dimension effects on airflow patterns and odorant deposition patterns in the rat nasal cavity.

The sense of smell is largely dependent on the airflow and odorant transport in the nasal cavity, which in turn depends on the anatomical structure of the nose. In order to evaluate the effect of airway dimension on rat nasal airflow patterns and odorant deposition patterns, we constructed two 3-dimensional, anatomically accurate models of the left nasal cavity of a Sprague-Dawley rat: one was based on high-resolution MRI images with relatively narrow airways and the other was based on artificially-widening airways of the MRI images by referencing the section images with relatively wide airways. Airflow and odorant transport, in the two models, were determined using the method of computational fluid dynamics with finite volume method. The results demonstrated that an increase of 34 mm in nasal airway dimension significantly decreased the average velocity in the whole nasal cavity by about 10% and in the olfactory region by about 12% and increased the volumetric flow into the olfactory region by about 3%. Odorant deposition was affected to a larger extent, especially in the olfactory region, where the maximum odorant deposition difference reached one order of magnitude. The results suggest that a more accurate nasal cavity model is necessary in order to more precisely study the olfactory function of the nose when using the rat.
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The Influence Of CSR Awareness On Consumer Purchase Decision Of A Telecommunication Network In Ghana A Case Of La Nkwantanag Madina Municipality

The Influence Of CSR Awareness On Consumer Purchase Decision Of A Telecommunication Network In Ghana A Case Of La Nkwantanag Madina Municipality

on overall company evaluations‖. Murray and Vogel (1997) have investigated the effect of associated CSR practices on consumers and presented similar findings. The CSR activities mentioned in the research are, for instance, environmental protection practices (energy conservation), engagement in acts to promote human welfare, corporate social marketing (electric safety education for schoolchildren), contribution to the economic development of the region, and consumer protection program. Their research found that CSR programs lead to improved customer attitudes towards the firm, including beliefs about the company‘s honesty, consumer responses, and increased support for the firm in labor or government disputes. Mohr et al. (2001) conducted a consumer interview project for investigating the impact of firms‘ CSR on consumer behavior. How well are consumers aware of the CSR level of individual firms? Are the purchase decisions of consumers affected by a firm‘s CSR, and how much? How do consumers think about firms‘ motivation for being socially responsible? Mohr et al. (2001) found that consumers are positive to business in general. It is not wrong to pursue economic interests. Consumers expect firms to be socially responsible. The attitudes of consumers toward socially responsible firms are more positive than toward irresponsible firms. Consumers are aware that socially responsible firms are helping themselves by practicing CSR. But this perception of consumers does not harm the positive consumer evaluations toward socially responsible firms. The study of Mohr et al. (2001) is enlightening for researchers, managers and policy makers. For managers specifically, it is clear that consumers do care about a firm‘s CSR and act accordingly. Some consumers are highly ethical in
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Operating characteristics of turbine mixers based on the analysis of power demand of the mixer’s drive

Operating characteristics of turbine mixers based on the analysis of power demand of the mixer’s drive

Optimisation of the turbine mixer’s performance during the preparations of the sand mix still remains an important issue as this mixer type is now in widespread use. Monitoring techniques of the system sand mixing include the analysis of electric power demand by the mixer’s drive based on measurements of power components. This study shows the operating characteristics of turbine mixers as the function of electric power demand by the drive system.

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Synthesis Of Arts In Architecture Of Uzbekistan Of The Ancient Period

Synthesis Of Arts In Architecture Of Uzbekistan Of The Ancient Period

was based on plastic contrast. For example, to emphasize the central part among the other composition, the architect 'in the middle third of the main wall had arranged an extensive (5.60 m) but shallow (75 cm) niche‖ [16, 46p]. The building itself was small in scale, and to emphasize its monumentality and visually to expand its interior, the sculptors correlated the height of zofor (1.40 m) to 6-meter span of the building. Frieze made with account of the angle of perspective, was decorated with garlands, supported by frames of children. The images of the frieze were original in the "very understanding of the ideal of human beauty and its artistic expression in plastic forms" [44, 61p]. Often in these images there was observed a deliberate asymmetry (in the faces), the disproportion (in the figures), aimed to correct the visual angle. For the sculpture in Toprak-kala "a rhythmic repetition of similar sculptural groups, determining architectonic division of interior, was characteristic" [45]. The style and the manner of sculpture, for example, of friezes were the same as of acanthus, volutes. So, it can be assumed that the ancient sculptors have been actively involved not only in the development of sculptures, but in architectural and decorative compositions (especially of capitals), and the connection between the latters was very tight. In general, the nature of decoration of the premises depended on the functions of the latter: "household and service rooms were modestly furnished, as for residential and ceremonial rooms they were finished with the appropriate splendor‖ [46, 67p]. The sculpture, obeying the architecture, served as an element of its design. In Bactria a monumental sculpture "was designed primarily to be installed in the temples" [22, 901p]. In architectural
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Model of knowledge representation about materials in the form of a relational database for CAPCAST system

Model of knowledge representation about materials in the form of a relational database for CAPCAST system

is the customer who gives the technical specification of the prod- uct and it is the customer who has to decide whether he can or cannot accept the price dictated by the manufacturer. Based on these restrictions, it is now the manufacturer who must decide whether he is able to execute the order (within the deadline ap- pointed and using the available facilities) and what will be the price of the product as dictated by the cost of production. Improv- ing the procedure of production costs estimation should improve the contract negotiations and make them more efficient. On the other hand, estimating the cost of production involves, among others, also the need to determine the type of material and treat- ment. The manufacturer can choose what materials he will use for the product and at what price, providing he can check which
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Double lateral designed for operating under single line conditions in irrigated citrus plantation in Brazil. DOI: 10.7127/rbai.v5n400042

Double lateral designed for operating under single line conditions in irrigated citrus plantation in Brazil. DOI: 10.7127/rbai.v5n400042

economic interpretation fulfils a central role not only because it provide the basis for support decisions, profits and losses, but also because incorporates criteria about water use and promotes social welfare (Hellegers, 2006). Therefore, the best trade- off between productivity losses and single line operation should be performed in order to estimate the optimal feasibility of doing the latter option and then surely support this widespread and frequent decision among orange growers, although simulating the former option is not only such a difficult task of modelling but also a challenge to experiment of fields. Otherwise, encouraging entrepreneurs to improvise their own lower-cost microirrigation systems might not be the best recommendation.
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J. Braz. Chem. Soc.  vol.18 número5

J. Braz. Chem. Soc. vol.18 número5

Secondary H-bonds are formed in solution and present a fast dynamic flip-flop character. This observation agrees with other studies (experimental and theoretical) on the structure of CDs either in solution or in the solid state. The molecule of γ-CD presents in solution a more symmetric structure when compared to α-, β-CD, as shown by the persistent chain of secondary H-bonds present in this molecule. We speculate that due to solvation effects, the secondary H-bonds do not confer as much rigidity to the CD molecules as in the solid state. If that would be the case, interactions between the CDs and high-polar solvents, such as water, may increase molecular flexibility allowing dynamical rearrangements of the structure with minimum energetic costs. Additional simulations of the CDs in low-dielectric solvents would be required to asses such assumption. The CDs cavities are known to be relatively hydrophobic, however the present simulation results show that the cavities are able to host water molecules, whose number and residence times depend on the size of the cavity. In summary, conformational variability in the molecular structure of CDs is assisted by interactions with water molecules suggesting that flexibility is strongly dependent on the chemical environment. The formation of H-bonds with neighbor glucose residues can significantly affect their confor- mational changes, and certainly the intrinsic flexibility of the CD molecules has a strong influence on the complexation mechanisms. Additionally, the findings presented here offer ground basis information for the novel design of carbohydrate-derived cyclic compounds and insights into their complexation mechanisms.
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CONTINUOUS CREATION IN THE PROBABILISTIC WORLD OF THE THEOLOGY OF CHANCE

CONTINUOUS CREATION IN THE PROBABILISTIC WORLD OF THE THEOLOGY OF CHANCE

I think we can answer this question in the positive: Yes, He can, because He is the most perfect being and His omnipotence is absolutely unlimited. A very important premise underlying the answer to the last question is that the risk is not so great, or even that it is very small. It is so because the nature and mechanism of the created world ensure with a very high proba- bility that all purposes intended by God will be attained without his causal action in the processes occurring in the world. The emergence of life in the universe is almost inevitable, because the universe is large and old enough, and biochemical mechanisms are very effective. The emergence of sentient beings was also almost inevitable because of longstanding and countless mutations and adaptations of living organisms to their environment. All this was very probable and hence in a sense necessary (inevitable). The great advantage of the non-deterministic world is its own creativity, which is possible because of the chance events happening in a way restricted only by the laws of nature. Thus, if one evolutionary path fails another one is opened. Perhaps a mutation suitable for the growth and development of a given species happened by chance and enabled it to survive in hard con- ditions and further develop. Elasticity and redundancy are very typical for the world of chance, but because of these properties, this world has a large number of possibilities and abilities to develop and regenerate after various natural catastrophes (Łukasiewicz 2006).
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