Investigation of Fracture Energy GF

Investigation of Fracture Energy GF ABSTRACT Concretes inherent brittleness, low tensile strength and premature micro-cracking phenomena can be improved, in the bulk material, by embedment of carbon nanotubes (CNTs), the 1-D allotrope of carbon which exhibit a remarkable combination of mechanical and transport properties. The present research aims in investigating the fracture energy, Gf, of modified cement mortar with Multi Wall Carbon Nanotubes (MWCNTs) under 3-point bending test with acoustic emission (AE). According to Rilem recommendation, it is reported that using the fracture toughness of mortars reinforced with variable loadings of multi-walled carbon nanotubes it can be determined the fracture energy, Gf. Moreover, it is widely known that fracture energy depends on both geometry and size of the test specimen. The results of load, CMOD, AE-activity and AE-energy are analyzed. 1. Introduction As the most widely used structural materials, concrete has been developed to meet constantly renewed requirements raised by construction of more and more structures [1]. Great research efforts are continuously invested towards improving its inherent brittleness, low tensile strength and premature micro-cracking phenomena by the introduction of third phases throughout its volume. While endowment of reinforcement and ductility are conventionally achieved through embedment of steel rods, additional reinforcement of the continuous phase can be achieved through the introduction of other micro- and nano-scale media [2-5]. However, an obvious shortage of concrete with largely enhanced strength grade is brittleness, which is of great concern related to the structural safety. Recent studies have focused on improving the properties of concrete with the addition of nanomaterials such as carbon nanotubes (CNTs) or carbon nanofibers (CNFs). In addition, fibers control the crack patterns and determine failure modes of concrete members [6-9]. There are many fibers utilized in cement and concrete materials. The most common fibers are glass, carbon, aramid, polypropylene, and basalt fibers. The revolutionary one-dimensional allotrope of carbon with Youngs moduli approaching 1.4 TPa, seven times higher than of high-strength steel and tensile strengths above 100GPa, fifty times higher than the same reference material. At this moment the nanocomposite materials are considered the next generation materials for electronics, aeronautical, civil engineering and other applications [4, 10-13]. Carbon nanotubes have minimum diameters of 0.4nm and are classified as single- or multi-walled (SWCNTs and MWCNTs, respectively) and they produced by chemical vapor deposition (CVD) and its variants (low pressure, thermal, catalytic and others). The most popular and affordable choice due to low commercial price are the ÃŽÅ“WCNTs but they have slightly inferior performance than SWCNTS which are lot expensive. Carbon nanofibers (CNFs), a similar nanostructured material comprised of cylindrically-shaped arrangements of stacked graphene plates or cones, have also been suggested as nano-re inforcements for concrete [14]. At nanocomposite materials a very important factor which will enable efficient load transfer from the cement matrix to the tubes, is the achievement of homogeneous dispersion of tubes within the continuous phase. The dispersion of MWCNTs, ideally without significant reduction in their high initial length and aspect ratio, usually achieved through the use of surfactants and sonication processes. This part attracts rigorous scientific efforts because CNTs tend to agglomerate together due to their high surface area and the strong Van der Waals forces acting between them. The agglomerates are responsible not only for stress concentration within the cement matrix which leads to strength degradation during service life, but also to premature crack initiation and propagation [15, 16]. On the other hand, there are a lot of studies which have referenced that surfactants create side-effects in cement matrix. Makar et al. reported strong early-age bonds between cement paste and CNTs[17]. Yazdanbakhsh [14] reported incompatibility issues, during the hydration phase, between cement base and the surfactants used for improving CNT dispersion. In addition the study observed reduction in aspect ratio length/diameter of MWCNT during exposure of the tubes to the high sonication energies required for disentanglement. It was suggested that the favorable dispersion characteristics found in aqueous environment does not guarantee a similarly favorable dispersion within the cement matrix. Enhancement of cements flexural toughness by CNTs hasnt been investigated largely by researchers and so there isnt a wide variety of reports. To the authors knowledge only one reference, Stynoski et al. [18] studied the fracture properties of Portland cement mortars containing carbon nanotubes, carbon fibers and silica fume using notched three-point bending test. They observed that using silica fume and carbon nanotubes together there was improvement in toughness about 35% and increment about 56% on critical crack tip opening displacement (CTODc) at 28 days. In addition using only carbon nanotubes provided. On the other hand, using only carbon nanotubes serves to increase in fracture toughness of about 5-10% at 7 and 28 days of age. In addition, the effect of carbon nanotubes has as result to increment the CTODc about 20% improvement at 28 days. But there are several of investigations which study the fracture properties of micro-fiber reinforced mortar with various additives. For exa mple, Moukwa et al. [19] studied the effect of alumino-silicate clays on the critical stress intensity factor and CTODc. They found that the use of silica fume and alumino-silicate clays increased the values of KIC, CTODC and the compressive strength of cementitious materials. In addition alumino-silicate clays are incorporated as substitutes for a fraction of the cement, the total porosity of hardened mixtures increases compared to that of hardened cement paste with no clay addition. Sarker et al. [20] studied the fracture behavior of geopolymer concrete (GPC) as compared to OPC concrete of similar compressive strength and containing the same size and type of aggregates. They found that the failure modes of the heat cured GPC specimens were generally more brittle than those of the OPC concrete specimens. Fracture energy of geopolymer concrete was similar to that of OPC concrete and fracture energy increased with compressive strength in both types of concrete. The critical stress in tensity factor of the GPC specimens was higher than that of the OPC concrete specimens for the same compressive strength and the difference in the fracture behaviors of GPC and OPC concrete is because of the higher bond and tensile strengths of GPC. Das et al. [21] replaced ordinary Portland cement (OPC) by limestone or a combination of limestone and fly ash/metakaolin and they observed that the new phases inside the mortar matrix can lead to enhanced fracture mechanics properties and ductility. Nikbin et al. [22] studied the fracture characteristics, such as fracture energy and Kic, of self-compacting concrete using notched three-point bend specimens for specimens with different coarse aggregate volume percent. 2. Materials and Test Methods 2.1. Materials, specimens and testing The Multi Walled Carbon Nanotubes (MWCNTs) that used in the present work were synthesized via catalytic chemical vapor deposition and were commercially available by Shenzhen Nanotech Port Co. Ltd. (Shenzhen, China). Their nominal purity was higher than 97% and their amorphous carbon content was less than 3%. The nominal tube diameter ranged from 20 to 40 nm while their length ranged from 5 to 15 ÃŽÂ ¼m. In table 1 is shown the properties of multi-wall carbon nanotubes. Viscocrete Ultra 300 (Sika AG, Baar, Switzerland), a water-based superplasticizer comprised of polycarboxylate polymers was used as dispersion assistive agent; it was selected based on its efficiency in inhibiting air entrapment inside the specimens as well as because of its excellent resistance to mechanical and chemical attack. Table 1: Properties of multi-wall carbon nanotubes Parameters Values Type multi-wall CNTs Length 5-15 ÃŽÂ ¼m Main range of diameter 20-40 nm Production method: catalyzed CVD Purity à ¢Ã¢â‚¬ °Ã‚ ¥ 95% Ash à ¢Ã¢â‚¬ °Ã‚ ¤ 0.2 wt% Special surface area 40-300 m3/g Amorphous carbon à ¢Ã¢â‚¬ °Ã‚ ¤ 3% For the production of nanocomposite mortar with tube loadings variable within 0.2, 0.4, 0.5, 0.6 and 0.8 wt% of cement, the following experimental protocol was adopted. Initially, superplasticer with MWCNTs at a ratio of 1.5/1 added in regular tap water and then follow magnetic stirring for 2 min. The resultant suspensions were subsequently ultrasonicated for 90 min at room temperature by aid of a Hielscher UP400S device (Hielscher Ultrasonics GmbH, Teltow, Germany) equipped with a cylindrical 22 mm diameter sonotrode delivering a power throughput of 4500 J/min at a frequency of 24 kHz. The specific combination of ultrasonication parameters was established as optimal for achievement of suspension homogeneity without tube aspect ratio impairment [15]. The ultrasonicated suspensions were transferred, along with ordinary Portland cement type I 42.5N and natural sand into the bucket of a rotary mixer where it was mixed for a total of 4 minutes, in low and high speeds sequentially, as per standard test method BS EN 196-1. Immediately after mixing, the fresh mortar was poured into metallic oiled formworks, volumes of 160x40x40 mm3, where it was left for 24 hours before demolding and subsequent placement into a 100% humidity room for duration of 28 days. A total 50 specimens were prepared, divided into two sets of five specimens at each CNT formulation, 0.2, 0.4, 0.6 and 0.8 wt% of cement. In one set, suspensions were further processed in a vacuum environment for removal of entrapped air before they were mixed with the cement and sand by aid of a rotary mixer. Additional mixtures without nanotubes were also prepared for reference purposes. The above procedure is shown schematically in fig. 1. After 28 days maturation were created a notch in specimens with cut-wheel with depth 20mm. Figure 1: Schematic representation of the nano-modifield mortars manufacturing process [5] In addition fig. 2 depicts the as-processed state of MWCNT-reinforced concrete specimens with varying tube loadings. The bottom row depicts reference specimens, whereas the top and middle rows show specimens with tube loadings of 0.6 and 0.2 wt% of cement, respectively, wherein porosity appears to increase with nano-reinforcement concentration. Figure 2: Various amounts of carbon nanotube loadings inside cement matrix: 0.6 wt% of cement (top row), 0.2 wt% of cement (middle row) and plain cement (bottom row) 2.2 Acoustic Emission Monitoring Large concrete structures like buildings, storage tanks, bridges, dams, offshore structures, flyovers require reliable non-destructive testing methods for assessing structure integrity. Acoustic emission is a widely used technique for monitoring concrete structures, and is based on the phenomenon of the rapid release of energy from different localized sources inside a material generating elastic waves [23]. Such stress waves propagate through the solid due to energy released during the deformation process and the amount of acoustic energy released depends on the size, the speed of the local deformation process and the material. AE can detect lesions such as crack growth, fracture growth, monitoring deformations, corrosion etc. in a wide range of materials. The transducers are usually piezoelectric and transform the energy of the transient elastic wave to an electric waveform which is digitized and stored. The AE sensors record the accumulated activity which is indicative of the sever ity of cracking. Certain indices based on the magnitude or the number of the AE signals has been employed successfully in the health monitoring of heterogeneous structural materials like concrete and composites. In addition, when multiple sensors are applied, apart from the number of AE hits, it is possible to be found the source of events because of the time delay between the acquisitions of the corresponding signals at different sensors. This allows the estimation of which part of the material needs repair, which is of paramount importance for large-scale structures. Also via AE the materials mode of fracture can be studied and characterized [24-26]. However, there are other important aspects of the AE testing, which are based on the qualitative parameters of the received signals. It has been seen that the shape of the waveform is indicative of the fracture type, something very important for the classification of cracks in different materials. Shear cracks follow tensile cracks as damage is being accumulated within the material. Therefore, the characterization of the cracking mode can act as a warning against final failure. It has been shown that tensile events are linked to higher frequency content and higher RA value, fig. 3, than shear [27-30]. This is mainly due to the larger part of energy transmitted in the form of shear waves, which are slower; therefore, the maximum peak of the waveform delays considerably compared to the onset of the initial longitudinal arrivals, This kind of classification has proven useful in laboratory conditions concerning corrosion cracking in concrete, fracture of cross-ply laminates, as well as d iscrimination between tensile matrix cracking and fiber pull-out during bending of steel-fiber reinforced concrete [31, 32]. In fig. 3 and in fig. 4 is given a typical AE signal and a typical AE signal due to different types of fracture respectively. Figure 3: Typical AE signal and parameters Figure 4: Typical AE signals due to different types of fracture 2.3 Mechanical performance Determination of the fracture toughness by means of three-point bend tests on notched beams In the present study for calculation of the critical fracture toughness of cementitious materials used the Hilleborgs [33] crack model of concrete which is similar with Dugdale-Barenblatt crack model of metals. For cementitious composite materials, such as mortar or concrete, the fracture toughness is determined using linear elastic fracture mechanics (LEFM) considerations. The P-CMOD response is obtained from notched beams, subjected to the center-point loading conà ¯Ã‚ ¬Ã‚ guration shown in fig. 5. The tests are performed under CMOD control, where this parameter is measured using a clip gage mounted on knife-edges. The thickness of the knife-edges, d, is taken into account in the calculations. Figure 5: Three-point bend test configuration for notched beam specimen For this geometry, the stress intensity factor (KI) is given by where P is the applied load, a is the crack length and ÃŽÂ ± = a / W is the relative crack length (with S=3W and ÃŽÂ ±o=ao/W=0,25). The geometry dependent function, f(ÃŽÂ ±) is determined using two-dimensional plane stress analysis and is given by Where when when Also, in a similar way, where the dimensionless geometry-dependent function, g(ÃŽÂ ±), is given by Where when when As it is evident from fig. 1, the CMOD is not measured exactly at the notch mouth but at a distance d, which must be taken into account for determining the real value of CMOD from that measured in the test (denoted as CMODMesured). Therefore, The conversion factor kd can be determined, for 1 mm d 6 mm, from The coefficients used to compute kd for the CMOD correction are given in table 2 for different knife-edge thicknesses. Table 2: Coefficients used to compute kd for the CMOD correction d(mm) h1 h2 h3 h4 1 0.0050 275.1 275.9 0.0399 2 0.1508 162.5 163.6 0.0118 3 0.1037 104.1 105.1 0.01631 4 0.0777 76.2 77.2 0.0137 5 0.0623 60.2 61.1 0.0117 6 0.0521 49.7 50.6 0.0106 For large ÃŽÂ ± (> 0,4) the correction is insignificant, hence for specimens with relative notch lengths in the order of 0,4, no correction needs to be applied. Moreover, for thin knife-edges (d Determination of the fracture energy by means of three-point bend tests on notched beams The fracture energy is defined as the amount of energy necessary to create one unit area of a crack. The area of a crack is defined as the projected area on a plane parallel to the main crack direction. This test method is not recommended for fiber-reinforced concrete. The fracture energy is determined by the equation, [N/m (J/] Where, Wo (Nm), is the area under the load-deformation curve shown in fig. 6 (kg) ; m1 = weight of the beam between the supports, calculated as the beam weight multiplied by S/L (fig. 1). The length L of the beam as well as the span S during the test must be measured with an accuracy of at least 1 mm; m2 = weigth of the part of the loading device touching the beam which is not attached to the testing machine, but follows the beam until fracture; g = acceleration due to gravity (9,81 m/s2); ÃŽÂ ´o = deformation of the beam at fracture (m), as shown in fig. 2; Alig = area of the ligament (m2), defined as the projection of the fracture zone on a plane perpendicular to the beam axis. Figure 6: Load-deformation (CMOD) curve Test procedure for fracture energy measurement The test is performed with an approximately constant rate of deformation, which is chosen so that the maximum load is reached within about 30-60 seconds after the start of the test. The deformation of the center of the beam and the corresponding load are registered until the beam is completely separated into two halves. In case the deformation is not measured directly on the specimen it is recommended that before measuring the load-deformation curve the load is cycled 3 times between 5% and 25% of the expected maximum load. The load should be measured with an accuracy of at least 2% of the maximum value in the test. The deformation must be measured with an accuracy of at least 0.01 mm. Finally, the Crack Mouth Opening Displacement (CMOD) will be monitored during the test performed with controlled load in a closed-loop testing machine. The load will be applied at a rate between 2 and 3 N/s. A plot of CMOD versus applied load will be produced. Mechanical characterization under three po int bending testing was performed on an Instron 5967 testing frame (Instron, Norwood, MA, USA) equipped with a 30kN loadcell. For the accurate recording of displacement C.M.O.D were used a Crack Opening Displacement (COD) Gauge extensometer with gauge length 10mm by Instron company. 3. Results and Discussion The effect of CNT presence and concentration to the flexural and compressive strength has investigated in previous study. The researchers were observed that subjection of the suspension to the vacuum-assisted air removal procedure significantly enhanced the materials flexural strength, compared to non-vacuumed suspensions. The maximum improvement in flexural strength, compared to the control specimens for vacuumed suspensions, appeared at 0.4 wt% MWCNT loading and was approximately 17% improvement at 0.2, 0.6 and 0.8 wt% loadings were 12, 10 and 9% respectively [4]. In the present study, the fracture energy of vacuum and non-vacuume nanocomposite mortar, Gf, as the way the fracture energy effects on the acoustic emission energy are investigated. In respect to the flexural strength the researcher observed that the specimens had the similar behavior as shown in table 3. The flexural strength calculated by using the following equation, where L, B, W and a0 are specimens dimensions prese nting in fig. 5. à Ã†â€™ = Table 3: Comparison results of Flexural strength between specimens with and without notch. Flexural Strength[MPa] [4] Flexural Strength with notch[Mpa] CNT loading, wt% of cement Non-VacuumedSuspensions VacuumedSuspensions Non-VacuumedSuspensions VacuumedSuspensions 0 (plain) 5.36  ± 0.38 5.43  ± 0.23 5.72  ± 0.21 5.64  ± 0.25 0.2 4.15  ± 0.28 6.09  ± 0.43 4.73  ± 0.22 5.98  ± 0.11 0.4 4.61  ± 0.48 6.34  ± 0.67 5.00  ± 0.34 6.74  ± 0.13 0.6 4.97  ± 0.36 6.01  ± 0.66 4.83  ± 0.33 6.12  ± 0.31 0.8 4.78  ± 0.21 5.92  ± 0.5 4.87  ± 0.28 6.35  ± 0.39 It is widely known that CNTs increase the mechanical properties. Table 4 shows the results of effect of CNTs to the fracture energy, Gf, for vacuumed and non-vacuumed specimens. It is clearly that CNTs increase the fracture energy and the maximum value appears in the rate of 0.4% wt. cement CNTs. Above the rate of 0.4% there were reduction in the fracture energy however the values of Gf continues are higher than control specimens. In addition, all non-vacuumed specimens showed slightly elevated values than the control specimens but lower for vacuumed specimens because of porosity which is created because of CNTs. Table 4: Comparison results of Fracture energy between Vacuumed and Non-Vacuumed suspensions Fracture Energy [N/m (J/m2)] CNT loading, wt% of cement Non-VacuumedSuspensions VacuumedSuspensions 0 (plain) 1.1655  ± 0.063 1.1281  ± 0.060 0.2 1.1681  ± 0.122 2.0338  ± 0.086 0.4 1.6910  ± 0.115 6.5373  ± 0.369 0.6 2.1460  ± 0.050 2.9987  ± 0.383 0.8 1.8185  ± 0.200 2.4623  ± 0.165 Except for plain specimens which had similar fracture energy, the fracture energy of the specimens which had been in vacuum was increased. Gf of the nanocomposite with 0.2% and 0.4% wt. cement CNTs was found to be higher at about 80% and 479% respectively related to control specimens while for 0.6% and 0.8% wt. cement CNTs was found an increment at about 166% and 118% respectively. On the other hand, non-vacuumed nanocomposite specimens with 0.2% wt. cement CNTs were found it that had limited growth about only 0.2%. Greater increase of approximately 45%, 84% and 56% showed the nanocomposites specimens with 0.4 %, 0.6% and 0.4% wt. cement CNTs respectively. Comparing the two types of mixtures, vacuumed and non-vacuumed, the results showed that the fracture energy increment for all rates for vacuumed specimens. Specifically, for the rates 0.2% and 0.4% wt. cement CNTs the increments were about 74% and 287% respectively while for 0.6% and 0.8% wt. the increments were only 40% and 36% re spectively. The entire above are shown in fig. 7. Finally, fig. 8 shows a typical load-CMOD graph for all rates, 0% up to 0.8% wt. cement CNTs, of vacuumed nanocomposite specimens and non-vacuumed specimens. Figure 7: Diagram of Fracture Energy, Gf, results Figure 8: Typical load-CMOD curve for all rates of nanocomposite specimens for a) vacuumed and b) non-vacuumed are presented. For Acoustic Emission (AE) monitoring in real time under three point bending tests of CNT-reinforced concrete specimens two R15a AE sensors were used, with broadband response ranging from 50 to 400 kHz and a maximum sensitivity at 150 kHz, attached on the lower section of the specimen. The R15a is a narrow band resonant sensor with a high sensitiv

Essay --

Introduction Considered to be the greatest playwright to ever have lived, William Shakespeare’s works continue to fascinate and entrance audiences around the world. Imbued with imagery, his comedy A Midsummer Night’s Dream is perhaps one of his more fantastic but none the less intricate plays. Presiding over the proceedings, the moon is the uniting feature of the play. With its multi-layered symbolism it is the thread that connects the different characters and weaves the tale together. 1. The Keeper of Time Upon its first mention the moon is used as a marker for the passage of time. In the opening lines of the play Theseus, the duke of Athens, laments to his fiancà ©e Hippolyta that time is passing too slow and blames this on the moon: THESEUS: Now, fair Hippolyta, our nuptial hour Draws on apace; four happy days bring in Another moon: but, O, methinks, how slow This old moon wanes! She lingers my desires, Like to a step-dame or a dowager Long withering out a young man’s revenue. (1.1.1-4 (Shakespeare and Brooks)) The old moon keeps Theseus waiting for his wedding night with Hippolyta, on the new moon. Theseus compares the old moon to an older woman, which stepmothers or a dowager usually are, and accuses her of keeping from him what is his to have, Hippolyta and their wedding night, like old widows might keep an inheritance from a young man. 2. The Moon Goddess Unlike the impatient Theseus, who mourns the dark moon, Hippolyta sees the moon as a symbol of Cupid and his arrows, which unite lovers: HIPPOLYTA: four nights will quickly steep themselves in night; Four nights will quickly dream away the time; And then the moon, like a silver bow New bent in heaven, shall behold the night Of our solemnity. (1.1.6-11 (Shakespeare and ... ...moon, therefore creating the image of the ‘Man in the Moon’: STARVELING: This lantern doth the horned moon present; Myself the Man i’th’ Moon do seem to be. (5.1.235-236 (Shakespeare and Brooks)) Thus the moon takes on another more comical and amusing role in contrast to the darker, more serious roles it holds towards the other groups. Conclusion Returning to the introduction, the moon is not only ever present, it actively influences the proceedings throughout the play, not only connecting characters, but also giving them agency for their actions. Shakespeare once again displays his dexterity with imagery through his manifold portrayals of the moon; one moment merely the indicator of time, the next a symbol of the goddess Diana, at once a symbol of order and chaos, of happiness and discord, fertility and chastity, it encompasses all that transpires on the stage.

Ashoka the Great

Ashoka From Wikipedia, the free encyclopedia â€Å"Asoka† redirects here. For other uses, see  Ashoka (disambiguation). |Ashoka the Great | |Mauryan  Samrat | |[pic] | |A Chakravatin (possibly Ashoka) first century BC/CE.Andhra Pradesh, | |Amaravati. Preserved at Musee Guimet | |Reign |273-232 BC | |Coronation |270 BC | |Full name |Ashoka Bindusara Maurya | |Titles |Samrat.Other titles include Devanampriya Priyadarsi, | | |Dhammarakhit, Dharmarajika, Dhammarajika, Dhammaradnya, | | |Chakravartin, Samrat, Radnyashreshtha, Magadhrajshretha, | | |Magadharajan, Bhupatin, Mauryaraja, Aryashok, Dharmashok, | | |Dhammashok, Asokvadhhan , Ashokavardhan, | | |Prajapita,Dhammanayak, Dharmanayak | |Born |304 BC | |Birthplace |Pataliputra,  Patna | |Died |232 BC (aged 72) | |Place of death |Pataliputra,  Patna | |Buried |Ashes immersed in theGanges  River, possibly | | |atVaranasi,  Cremated  232 BC, less than 24 hours after death | |Predecessor |Bindusara | |Successor |Dasa ratha Maurya | |Consort |Maharani Devi | |Wives |Rani  Tishyaraksha | | |Rani  Padmavati | | |Rani  Kaurwaki | |Offspring |Mahendra,Sanghamitra,Teevala, Kunala | |Royal House |Mauryan dynasty | |Father |Bindusara | |Mother |Rani Dharma or Shubhadrangi | |Religious |Buddhism,Humanism | |beliefs | | Ashoka  (Devanagari: ,  IAST:  Asoka,  IPA:  [a o? k? , 304–232 BC), popularly known as  Ashoka the Great, was an  Indian  emperor  of the  Maurya Dynasty  who ruled almost all of the  Indian subcontinent  from 269 BC to 232 BC. One of India's greatest emperors, Ashoka reigned over most of present-day India after a number of military conquests. His empire stretched from present-dayPakistan,  Afghanistan  in the west, to the present-day  Bangladesh  and the Indian state of  Assam  in the east, and as far south as northern  Kerala  andAndhra. He conquered the kingdom named  Kalinga, which no one in his dynasty had conquered starting f rom  Chandragupta Maurya. His reign was headquartered in  Magadha  (present-day  Bihar, India). 1]He embraced  Buddhism  from the prevalentVedic  tradition after witnessing the mass deaths of the  war of Kalinga, which he himself had waged out of a desire for conquest. He was later dedicated to the propagation of Buddhism across  Asia  and established monuments marking several significant sites in the life of  Gautama Buddha. Ashoka was a devotee of  ahimsa  (nonviolence),  love,  truth,tolerance  and  vegetarianism. Ashoka is remembered in history as a  philanthropicadministrator. In the  history of India  Ashoka is referred to as  Samraat  Chakravartin  Ashoka- the Emperor of Emperors  Ashoka. His name â€Å"asoka† means â€Å"without sorrow† inSanskrit  (a= no/without, soka= sorrow or worry).In his  edicts, he is referred to as Devanampriya (Devanagari: )/Devana? iya  or â€Å"The Beloved Of The Gods†, an d Priyadarsin (Devanagari: )/Piyadassi  or â€Å"He who regards everyone with affection†. Another title of his is Dhamma (prakrit: ), â€Å"Lawful, Religious, Righteous†. Renowned  British  author and  social critic  H. G. Wells  in his bestselling two-volume work,  The Outline of History  (1920), wrote of emperor Ashoka: In the history of the world there have been thousands of kings and emperors who called themselves ‘their highnesses,' ‘their majesties,' and ‘their exalted majesties' and so on. They shone for a brief moment, and as quickly disappeared. But Ashoka shines and shines brightly like a bright star, even unto this day.Along with the  Edicts of Ashoka, his legend is related in the later second century  Asokavadana(â€Å"Narrative of Asoka†) and  Divyavadana  (â€Å"Divine narrative†), and in the  Sri Lankan  text  Mahavamsa(â€Å"Great Chronicle†). After two thousand years, the influence of Ashoka is seen in  Asia  and especially the  Indian subcontinent. An emblem excavated from his empire is today the national  Emblem of India. In the  History of Buddhism  Ashoka is considered just afterGautama Buddha. |Contents | |  [show] | Biography Early life |[pic] |This article  needs additional  citations  for  verification. | | |Please help  improve this article  by adding  reliable references.Unsourced | | |material may be  challenged  and  removed. (January 2009) | Ashoka was born to the  Mauryan  emperor  Bindusara  and his Queen ‘Dharma' (although she was a  Brahmin  or Shubhadrangi, she was undervalued as she wasn't of royal blood). Ashoka had several elder siblings (all half-brothers from other wives of Bindusara). He had just one younger sibling, Vitthashoka (a much loved brother from the same mother). Because of his exemplary intellect and warrior skills, he was said to have been the favorite of his grandfather  Chandragupta Maurya. As the legend goes, when Chandragupta Maurya left his empire for a  Jain  living, he threw his  sword  away. Ashoka ound the sword and kept it, in spite of his grandfather's warning. Ashoka, in his adolescence, was rude and naughty.He was a fearsome hunter. He was akshatriya  and was given all royal military trainings and other  Vedic  knowledge. According to a legend, he killed a Lion with just a wooden rod. Ashoka was very well known for his sword fighting. He was very adventurous and this made him a terrific fighter. Ashoka was a frightening warrior and a heartless general. Because of this quality he was sent to destroy the riot of  Avanti. Rise to power [pic] [pic] Maurya Empire  at the age of Ashoka. The empire stretched from  Iran  to  Bangladesh/Assam  and from  Central Asia  (Afganistan) to  Tamil Nadu/South India.Developing into an impeccable warrior general and a shrewd statesman, Ashoka went on to command several regim ents of the Mauryan army. His growing popularity across the empire made his elder brothers wary of his chances of being favored by  Bindusarato become the next emperor. The eldest of them,  Susima, the traditional heir to the throne, persuaded Bindusara to send Ashoka to quell an uprising inTaxshila, a city in the north-west District of Pakistani Punjab region, for which Prince Susima was the Governor. Taxshila was a highly volatile place because of the war-like Indo-Greek population and mismanagement by Susima himself. This had led to the formation of different militias causing unrest. Ashoka complied and left for the troubled area.As news of Ashoka's visit with his army trickled in, he was welcomed by the revolting militias and the uprising ended without a conflict. (The province revolted once more during the rule of Ashoka, but this time the uprising was crushed with an iron fist) Ashoka's success made his stepbrothers more wary of his intentions of becoming the emperor and m ore incitements from Susima led Bindusara to send Ashoka into exile. He went intoKalinga  and stayed there incognito. There he met a fisher woman named  Kaurwaki, with whom he fell in love. Recently found inscriptions indicate that she would later become either his second or third queen. Meanwhile, there was again a violent uprising in  Ujjain.Emperor Bindusara summoned Ashoka out of exile after two years. Ashoka went into Ujjain and in the ensuing battle was injured, but his generals quelled the uprising. Ashoka was treated in hiding so that loyalists of the Susima group could not harm him. He was treated by  Buddhist  monks and nuns. This is where he first learned the teachings of the  Buddha, and it is also where he met Devi, who was his personal nurse and the daughter of a merchant from adjacent Vidisha. After recovering, he married her. It was quite unacceptable to Bindusara that one of his sons should marry a Buddhist, so he did not allow Ashoka to stay in  Patal iputra  but instead sent him back to Ujjain and made him the governor of Ujjain.The following year passed quite peacefully for him, and Devi was about to deliver his first child. In the meanwhile, Emperor Bindusara died. As the news of the unborn heir to the throne spread, Prince Susima planned the execution of the unborn child; however, the assassin who came to kill Devi and her child killed his mother instead. Ashoka beheads his elder brother to ascend the throne. In this phase of his life, Ashoka was known for his unquenched thirst for wars and campaigns launched to conquer the lands of other rulers and became known as Chandashok (terrible Ashoka), the Sanskrit word  chanda  meaning cruel, fierce, or rude,  Chandi-devi being associated with  Kali.Ascending the throne, Ashoka expanded his empire over the next eight years, from the present-day boundaries and regions of  Burma–Bangladesh  and the state of  Assam  in India in the east to the territory of pres ent-day  Iran  /  Persia  and  Afghanistan  in the west; from the  Pamir  Knots in the north almost to the peninsular of  southern India  (i. e. Tamilnadu  /  Andhra pradesh). Conquest of Kalinga Main article:  Kalinga War While the early part of Ashoka's reign was apparently quite bloodthirsty, he became a follower of the  Buddha's teaching after his conquest of Kalinga on the east coast of India in the present-day state of  Orissa. Kalinga was a state that prided itself on its sovereignty and democracy. With its monarchical parliamentary democracy it was quite an exception in ancient Bharata where there existed the concept of  Rajdharma. Rajdharma means the duty of the rulers, which was intrinsically entwined with the concept of bravery and  Kshatriya  dharma.The pretext for the start of the  Kalinga War  (265 BC or 263 BC) is uncertain. One of Susima's brothers might have fled to Kalinga and found official refuge there. This enraged Ashoka immensely. He was advised by his ministers to attack Kalinga for this act of treachery. Ashoka then asked Kalinga's royalty to submit before his supremacy. When they defied this diktat, Ashoka sent one of his generals to Kalinga to make them submit. The general and his forces were, however, completely routed through the skilled tact of Kalinga's commander-in-chief. Ashoka, baffled at this defeat, attacked with the greatest invasion ever recorded in Indian history until then.Kalinga put up a stiff resistance, but they were no match for Ashoka's brutal strength. The whole of Kalinga was plundered and destroyed. Ashoka's later edicts state that about 100,000 people were killed on the Kalinga side and 10,000 from Ashoka's army. Thousands of men and women were deported. Buddhist conversion |[pic] |This article  needs additional  citations  for  verification. | | |Please help  improve this article  by adding  reliable references. Unsourced | | |material may be  challengedà ‚  and  removed. (March 2009) | [pic] [pic] A similar four â€Å"Indian lion† Lion Capital of Ashoka atop an ntact  Ashoka Pillar  at Wat U Mong near Chiang Mai,  Thailandshowing another larger  Dharma Chakra  /Ashoka Chakra  atop the four lions thought to be missing in the Lion Capital of Ashoka at  Sarnath Museum  which has been adopted as the  National Emblem of India. As the legend goes, one day after the war was over, Ashoka ventured out to roam the city and all he could see were burnt houses and scattered corpses. This sight made him sick and he cried the famous monologue: What have I done? If this is a victory, what's a defeat then? Is this a victory or a defeat? Is this justice or injustice? Is it gallantry or a rout? Is it valor to kill innocent children and women? Do I do it to widen the empire and for prosperity or to destroy the other's kingdom and splendor?One has lost her husband, someone else a father, someone a child, someone an unborn infa nt†¦. What's this debris of the corpses? Are these marks of victory or defeat? Are these vultures, crows, eagles the messengers of death or evil? The brutality of the conquest led him to adopt Buddhism and he used his position to propagate the relatively new religion to new heights, as far as ancient Rome and Egypt. He made Buddhism his state religion around 260 BC, and propagated it and preached it within his domain and worldwide from about 250 BC. Emperor Ashoka undoubtedly has to be credited with the first serious attempt to develop a Buddhist policy. [pic] [pic] Ashokan Pillar at  VaishaliProminent in this cause were his son VenerableMahindra  and daughter  Sanghamitra  (whose name means â€Å"friend of the Sangha†), who established Buddhism in Ceylon (now  Sri Lanka). He built thousands of Stupas and Viharas for Buddhist followers. The Stupas of Sanchi are world famous and the stupa named  Sanchi Stupa  was built by Emperor Ashoka. During the remaining portion of Ashoka's reign, he pursued an official policy of  nonviolence  (ahimsa). Even the unnecessary slaughter or mutilation of people was immediately abolished. Everyone became protected by the king's  law  against sport hunting and branding. Limited hunting was permitted for consumption reasons but Ashoka also promoted the concept of vegetarianism.Ashoka also showed mercy to those imprisoned, allowing them leave for the outside a day of the year. He attempted to raise the professional ambition of the common man by building universities for study, and water transit and irrigation systems for trade and agriculture. He treated his subjects as equals regardless of their religion, politics and caste. The kingdoms surrounding his, so easily overthrown, were instead made to be well-respected allies. He is acclaimed for constructing hospitals for animals and renovating major roads throughout India. After this transformation, Ashoka came to be known as Dhammashoka (Sanskrit), meaning Ashoka, the follower of Dharma.Ashoka defined the main principles of dharma (dhamma) as nonviolence, tolerance of all sects and opinions, obedience to parents, respect for the Brahmans and other religious teachers and priests, liberality towards friends, humane treatment of servants, and generosity towards all. These principles suggest a general ethic of behaviour to which no religious or social group could object. Some critics say that Ashoka was afraid of more wars, but among his neighbors, including theSeleucid Empire  and the Greco-Bactrian kingdom established by  Diodotus I, none could match his strength. He was a contemporary of both  Antiochus I Soter  and his successor  Antiochus II Theos  of the Seleucid dynasty as well as  Diodotus I  and his son  Diodotus II  of the Greco-Bactrian kingdom.If his inscriptions and edicts are well studied one finds that he was familiar with the Hellenic world but never in awe of it. His edicts, which talk of frien dly relations, give the names of both Antiochus of the Seleucid empire and  Ptolemy III  of  Egypt. The fame of theMauryan  empire was widespread from the time that Ashoka's grandfather  Chandragupta Mauryadefeated  Seleucus Nicator, the founder of the Seleucid Dynasty. [pic] [pic] Stupa of  Sanchi. The source of much of our knowledge of Ashoka is the many inscriptions he had carved on pillars and rocks throughout the empire. Emperor Ashoka is known as Piyadasi (in  Pali) or Priyadarshi (in  Sanskrit) meaning â€Å"good looking† or â€Å"favored by the gods with good blessing†.All his inscriptions have the imperial touch and show compassionate loving. He addressed his people as his â€Å"children†. These inscriptions promoted Buddhist morality and encouraged nonviolence and adherence to Dharma (duty or proper behavior), and they talk of his fame and conquered lands as well as the neighboring kingdoms holding up his might. One also gets some pri mary information about the Kalinga War and Ashoka's allies plus some useful knowledge on the civil administration. The Ashoka Pillar at  Sarnath  is the most popular of the relics left by Ashoka. Made of sandstone, this pillar records the visit of the emperor to Sarnath, in the third century BC.It has a four-lion capital (four lions standing back to back) which was adopted as the emblem of the modern Indian republic. The lion symbolizes both Ashoka's imperial rule and the kingship of the  Buddha. In translating these monuments, historians learn the bulk of what is assumed to have been true fact of the Mauryan Empire. It is difficult to determine whether or not some actual events ever happened, but the stone etchings clearly depict how Ashoka wanted to be thought of and remembered. Ashoka's own words as known from his  Edicts  are: â€Å"All men are my children. I am like a father to them. As every father desires the good and the happiness of his children, I wish that all men should be happy always. Edward D'Cruz interprets the Ashokan dharma as a â€Å"religion to be used as a symbol of a new imperial unity and a cementing force to weld the diverse and heterogeneous elements of the empire†. Also, in the Edicts, Ashoka mentions Hellenistic kings of the period as converts to Buddhism, although no Hellenic historical record of this event remain: The conquest by  Dharma  has been won here, on the borders, and even six hundred  yojanas  (5,400–9,600 km) away, where the Greek king  Antiochos  rules, beyond there where the four kings named  Ptolemy,  Antigonos,  Magas  andAlexander  rule, likewise in the south among the  Cholas, the  Pandyas, and as far as  Tamraparni  (Sri Lanka). —Edicts of Ashoka,  Rock Edict  13 (S. Dhammika)Ashoka also claims that he encouraged the development of  herbal medicine, for human and nonhuman animals, in their territories: Everywhere within Beloved-of-the-Gods, King P iyadasi's [Ashoka's] domain, and among the people beyond the borders, the  Cholas, the  Pandyas, the Satiyaputras, the Keralaputras, as far as  Tamraparni  and where the Greek king  Antiochos  rules, and among the kings who are neighbors of Antiochos, everywhere has Beloved-of-the-Gods, King Piyadasi, made provision for two types of medical treatment: medical treatment for humans and medical treatment for animals. Wherever medical herbs suitable for humans or animals are not available, I have had them imported and grown.Wherever medical roots or fruits are not available I have had them imported and grown. Along roads I have had wells dug and trees planted for the benefit of humans and animals. —Edicts of Ashoka,  Rock Edict  2 The Greeks in India even seem to have played an active role in the propagation of Buddhism, as some of the emissaries of Ashoka, such as  Dharmaraksita, are described in  Pali  sources as leading Greek (Yona) Buddhist monks, active in spreading Buddhism (the  Mahavamsa, XII[2]). Death and legacy Ashoka ruled for an estimated forty years. After his death, the Mauryan dynasty lasted just fifty more years. Ashoka had many wives and children, but many of their names are lost to time.Mahindra  and  Sanghamitra  were twins born by his first wife, Devi, in the city of  Ujjain. He had entrusted to them the job of making his state religion, Buddhism, more popular across the known and the unknown world. Mahindra  and  Sanghamitra  went into  Sri Lanka  and converted the King, the Queen and their people to Buddhism. They were naturally not handling state affairs after him. In his old age, he seems to have come under the spell of his youngest wife  Tishyaraksha. It is said that she had got his son  Kunala, the regent in  Takshashila, blinded by a wily  stratagem. The official executioners spared Kunala and he became a wandering singer accompanied by his favourite wife  Kanchanmala.In  Pata liputra, Ashoka hears Kunala's song, and realizes that Kunala's misfortune may have been a punishment for some past sin of the emperor himself and condemns Tishyaraksha to death, restoring Kunala to the court. Kunala was succeeded by his son,  Samprati, but his rule did not last long after Ashoka's death. The reign of Ashoka Maurya could easily have disappeared into history as the ages passed by, and would have had he not left behind a record of his trials. The testimony of this wise king was discovered in the form of magnificently sculpted pillars and boulders with a variety of actions and teachings he wished to be published etched into the stone.What Ashoka left behind was the first written language in India since the ancient city of  Harappa. The language used for inscription was the then current spoken form called  Prakrit. In the year 185 BC, about fifty years after Ashoka's death, the last Maurya ruler,  Brhadrata, was assassinated by the commander-in-chief of the Maur yan armed forces,  Pusyamitra Sunga, while he was taking the Guard of Honor of his forces. Pusyamitra Sunga founded the  Sunga dynasty(185 BC-78 BC) and ruled just a fragmented part of the Mauryan Empire. Many of the northwestern territories of the Mauryan Empire (modern-day Iran, Afghanistan and Pakistan) became the  Indo-Greek Kingdom.When India gained independence from the  British Empire  it adopted Ashoka's emblem for its own, placing the  Dharmachakra  (The Wheel of Righteous Duty) that crowned his many columns on the  flag  of the newly independent state. In 1992, Ashoka was ranked #53 on  Michael H. Hart's  list of the most influential figures in history. In 2001, a semi-fictionalized portrayal of Ashoka's life was produced as a motion picture under the title  Asoka. King Ashoka, the third monarch of the Indian Mauryan dynasty, has come to be regarded as one of the most exemplary rulers in world history. The British historian H. G. Wells has written: â€Å"Amidst the tens of thousands of names of monarchs that crowd the columns of history †¦ the name of Asoka shines, and shines almost alone, a star. â€Å"

Steam Jet Refrigeration System - 1967 Words

A Seminar Report On Working Principal of Steam jet refrigeration system Submitted by Amit Prakash Roll No-1126004 Department of Mechanical Engineering National Institute of Technology, Patna Patna-800005, Bihar (India) Candidate Declaration This is to certify that seminar report entitled Working principle of Steam jet refrigeration system has been prepared by me under the supervision of Dr. Amarnath Sinha Professor†¦show more content†¦Flashing a portion of the water in the tank reduces the liquid temperature. Figure 3.66 presents a schematic arrangement of a steam jet refrigeration system for water cooling. In the system shown, high-pressure steam expands while flowing through the nozzle 1. The expansion causes a drop in pressure and an enormous increase in velocity. Steam flows through the ejector (or sometimes called an eductor or venturi) and creates a low pressure zone in the branch nozzle of the ejector. 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