High Fracture Toughness of Al2O3-TiN0.3 Composites

High Fracture Toughness of Al2O3-TiN0.3 Composites High fracture toughness of Al2O3-TiN0.3 composites prepared via spark plasma sintering Lina Qiaoa, b, Yucheng Zhaoa, Mingzhi Wanga, à ¯Ã‚ Ã¢â‚¬ ºÃƒ ¯Ã¢â€š ¬Ã‚ ªÃƒ ¯Ã‚ Ã‚ , Yana Yea, Junxing Zhanga, Qin Zoua, Qian Yanga, Hua Dengc, Ying Xingc Abstract Al2O3–TiN0.3 composites with different TiN0.3 contents were spark plasma sintered at 1300–1600  °C for 10 min. Phase identification was characterized through X-ray diffraction. Microstructures were observed using a scanning electron microscope. The fracture toughness of the composite with 30 vol% TiN0.3 sintered at 1500  °C reaches to the highest value of 6.91 MPa m1/2. Based on the first-principles density functional theory, the density of states for TiN and TiNx was calculated. The covalent bonding is weakened and the metallic bonding is strengthened as the nitrogen concentration is reduced in nonstoichiometric TiNx. The active slip systems determined by covalent bonding for the nitrides are possibly increased by adding nonstoichiometric TiN0.3, which improves the fracture toughness of Al2O3-based composites. Keywords: Al2O3–TiN0.3 composites;Fracture toughness; Slip system; Bond calculation 1. Introduction Alumina (Al2O3) ceramics are essential structural materials, but the inherent brittleness has inhibited their applications [1, 2]. The fracture toughness can be improved substantially by adding a secondary reinforcing phase into the matrix. The effects of TiN particles on the mechanical properties of Al2O3-based composites have been widely studied [3–9]. Shen et al. [9] reported that the fracture toughness of Al2O3–TiN composites prepared via spark plasma sintering (SPS) at 1500  °C reaches to a maximum value of 5.7 MPa m1/2. Li et al. [1] studied the mechanical properties of TiN–Al2O3 nanocomposites prepared by hot pressing at 1550  °C, and pointed out that the highest fracture toughness is 5.27 MPa m1/2. However, there have been few reports about the effects of nonstoichiometric TiN0.3 on the fracture toughness of Al2O3-based composites. In this study, nonstoichiometricTiN0.3 was added into Al2O3 matrix, and the effects of TiN0.3 on the mechanical properties (especially fracture toughness) of the composites were discussed. Nonstoichiometric TiN0.3 synthesized via mechanical alloying (MA) possesses fine grain size and TiN-type structure with numerous N vacancies [10, 11], which are conducive to improving sinterability [11–14]. Furthermore, weakening covalent bond and strengthening metallic bond in TiN0.3 structure [15, 16] may have an important influence on the fracture toughness. This study aims to verify whether or not adding nonstoichiometric materials can increase the fracture toughness of Al2O3-based composites. 2. Experimental Raw materials used include TiN0.3 synthesized through MA [10, 11] and commercial powders Al2O3 (analytically pure, an average particle size of 1 ÃŽ ¼m). Powder mixtures were milled for 2 h in absolute ethanol using WC milling media on a Pulverisette 4 Vario-Planetary Mill (FRTSCH German) at 300 rpm. SPS (3.20 MK-IV, Sumitomo Coal Mining Co., Ltd.) was performed in vacuum (6Ãâ€"10−3 Pa) at different heat treatment temperatures (1300–1600  °C) for 10min at 30 MPa. The heating rate was 100  °C/min. The temperature was determined using an optical pyrometer focused on the non-through hole located on the surface of the graphite die. Phase identification was performed through X-ray diffraction (XRD) with Cu KÃŽ ± radiation by using a D/MAX-2500PC diffractometer (Rigaku). Microstructures of the specimen’s polished surface and fracture cross-sections were observed using an S-3400N (Hitachis) scanning electron microscope (SEM) equipped with electron back-scattered diffraction (Edax-Tsl, Ametek). The bending strength was measured with Instron-5848 MicroTester (America) using the three point bending test with a span length of 13 mm and crosshead speed of 0.5 mm/min. Fracture toughness was determined through the Vickers indentation method proposed by Anstis et. al [17]. Measurements of the hardness and fracture toughness were conducted using an FM-700 Vickers hardness tester (Future-Tech, Japan) by indentation using a pyramidal indenter and applying a 10 kg load for 10 s. 3. Results 3.1 XRD identification and morphology observation Fig. 1 shows the XRD patterns of Al2O3–30 vol% TiN0.3 composite sintered via SPS at different temperatures in vacuum (6Ãâ€"103 Pa) for 10 min. Only TiN0.3 and ÃŽ ±-Al2O3 phases are detected in the XRD patterns. It suggests that no chemical reaction occurs between the second phase and the matrix. Fig. 2 shows the back-scattered SEM micrograph of the polished surface of Al2O3–30 vol% TiN0.3 composite sintered via SPS at 1400  °C in vacuum (6Ãâ€"103 Pa) for 10 min. The gray grains are Al2O3, while the white ones are TiN0.3. TiN0.3 grains are uniformly dispersed in Al2O3 matrix. Fig. 3 shows the microstructure of the fracture cross-sections of Al2O3–30 vol% TiN0.3 composite sintered via SPS at different temperatures in vacuum (6Ãâ€"103 Pa) for 10 min. When the sintering temperature is raised to 1400  °C, the grain size of the composite is fine and approximately 2 ÃŽ ¼m for Al2O3; the fracture mode is mainly intergranular (Fig. 3 b). Then the gains grew obviously with further raising the sintering temperature, here ~3-4 ÃŽ ¼m at 1500  °C and ~4-5 ÃŽ ¼m at 1600  °C for Al2O3; the fracture modes are intergranular and transgranular (Fig. 3 c and d). In addition, Al2O3–30 vol% TiN0.3 composite has not reached full density at 1300  °C, as indicated both by the SEM observations (Fig. 3) and measured hardness values (Fig. 5). Fig. 4 shows the microstructure of the fracture cross-sections of Al2O3–TiN0.3 composites with different TiN0.3 contents sintered via SPS at 1400  °C in vacuum (6Ãâ€"103 Pa) for 10 min. The grain size of Al2O3 existed in all samples does not change significantly. It is not agreement with the previous study that the addition of TiN effectively inhibits the grain growth of Al2O3 [9]. This phenomenon may be attributed to the fact that Al2O3–TiN0.3 composites have good sinterability. In addition, the fracture morphology is influenced by TiN0.3 content in these samples. The fracture mode of Al2O3–TiN0.3 composites with TiN0.3 contents from 10 vol% to 30 vol% (Fig. 4 a–c) is mainly intergranular. But, the fracture modes of Al2O3–TiN0.3 composite with 40 vol% TiN0.3 (Fig. 4 d) are intergranular and transgranular. The explanation for the fracture mode change is that the grain boundaries in Al2O3–TiN0.3 composites are strengthened, inhibiting inter granular crack propagation. 3.2 Mechanical properties Fig. 5 a shows the Vickers hardness of Al2O3–30 vol% TiN0.3 composite sintered at different temperatures. The Vickers hardness of Al2O3–30 vol% TiN0.3 composite sintered at 1400  °C reaches to the highest value of 18.75 GPa, then slightly reduces with raising the sintering temperature, which is due to grain growth [9, 18, 19] (Fig. 3 b-d). Fig. 5 b shows the Vickers hardness of Al2O3–TiN0.3 composites sintered at 1400  °C versus TiN0.3 content. The Vickers hardness of Al2O3–TiN0.3 composites with different TiN0.3 contents from 10 vol% to 40 vol% reaches to a range of 17–19 GPa, which is no significant difference from that of pure Al2O3 and close to that of Al2O3–TiN nanocomposites [1]. Fig. 6 shows the bending strength of Al2O3–TiN0.3 composites sintered at 1400  °C versus TiN0.3 content. The bending strength of Al2O3–TiN0.3 composites sintered at 1400  °C increases with increasing TiN0.3 contents from 10 vol% to 40 vol%, and is higher than that of Al2O3 ceramics. As adding TiN0.3 into Al2O3 matrix, the microstructure is improved and the grain boundaries are strengthened, which lead to an increase in the bending strength of Al2O3–TiN0.3 composites. The fracture toughness of the composite with 30 vol% TiN0.3 sintered at 1500  °C reaches to the highest value of 6.91 MPa m1/2, as shown in Fig. 5 a, which is much higher than that of nano- or micron-sized Al2O3–TiN composites [1, 4, 5, 9, 20]. And the fracture toughness of the composites sintered at 1400  °C increases with the addition of TiN0.3, and presents a maximum value of 6.60 MPa m1/2 at 30 vol% TiN0.3, then decreases with further increasing the amount of TiN0.3, as shown in Fig. 5 b. These results are in agreement with previous studies [1, 4, 5, 9, 20]. For particulate reinforced composites, many toughening mechanisms such as crack pinning, microcrack toughening, crack deflection, residual stress toughening and crack bridging have been proposed. For TiN–Al2O3 composites, Li et al. [1] reported that possible toughening mechanisms are crack deflections and/ or crack pinning; Shen et al. [9] pointed out that the predominating toughening mechanism is related to crack tilting and twisting caused by thermal expansion and/ or elastic modulus mismatch stresses. It is difficult to indicate a prevailing toughening mechanism. In this research, maybe some of these toughening mechanisms are active at the same time. Nonetheless, due to structure defect, TiN0.3 may have an important influence on the fracture toughness. It will be discussed subsequently in more detail. 4. Discussion The above experimental results suggest that adding a nonstoichiometric TiN0.3 phase is more effective for improving the fracture toughness of Al2O3-based composites. To explain the phenomenon, based on the first-principles density functional theory [15, 16, 21], the density of states (DOS) for TiN and TiNx was calculated, as shown in Fig 7. Close to the Fermi level, the DOS for TiN consists of hybridized Ti-3d and N-2p states, as shown in Fig. 7. It can be seen that the DOS for TiN at the Fermi level is not at the minimum and mainly dominated by Ti-3d states. This is an evidence that the cohesion in TiN is a complex mixture of covalent, ionic (a little) and metallic types. The new structures in the DOS for TiNx near the Fermi level can clearly be seen in Fig. 7, which are called ‘vacancy state associated structures’ [15, 16]. It can be explained by symmetry changes resulting from the vacancy sites in the lattice. Titanium atoms are completely equivalent in a perfect stoichiometric rocksalt structure. But, in a nonstoichiometric structure, both Ti neighboring levels of symmetry interact together through a vacancy (symbolized by à ¢- ¡) to establish a Ti–à ¢- ¡Ã¢â‚¬â€œTi bond which is absent in the stoichiometric titanium compound. In other words, the covalent bonding is weakened and the metallic bonding is strengthened as the nitrogen concentration is reduced in nonstoichiometric TiNx, which are indicated by the peaks observed near the Fermi level on the DOS curves in Fig. 7 and in accordance with Refs. [15, 16]. Al2O3 is a kind of brittle material due to the lack of active slip system essentially. The active slip systems determined by covalent bonding for the nitrides can be increased by adding a nonstoichiometric material. Rowcliffe et al. [22] had reported that TiC has the {111} 0> slip system at high temperature and the {110} 0> slip system at room temperature. The root cause of the change of the slip systems is that the cohesion in TiC is a complex mixture of covalent, ionic (a little) and metallic types. At low temperature, the bonding is covalent with strong, directional bonding between neighboring carbon and metal atoms; as the temperature is raised, electrons are transferred from these bonds into less localized metallic states. Such a transfer has the effect of reducing both the directionality and strength of the bonds. They also pointed out that the covalent contribution to bonding becomes less as the carbon concentration in nonstoichiometric TiCx decreases [20]. TiC and TiN crystals belong to the same space group (FM-3M, cubic system) and the atomic radii of C and N are closed. It is inferred that TiN (or TiNx) has the similar slip system. Same as previous analysis, the nitrogen concentration in TiN0.3 is very low, which leads to weakening covalent bond and strengthening metallic bond. Maybe the {111} 0> slip system, or some of it, is active at room temperature. In other words, there may be more active slip systems at room temperature in Al2O3–TiN0.3 composites. This is a major reason for the improvement of the fracture toughness of Al2O3–TiN0.3 composites. 4. Conclusions This paper introduces a new and effective method to improve the fracture toughness of Al2O3-based composites by adding a nonstoichiometric material. Al2O3–TiN0.3 composites were prepared via SPS at a relatively low temperature. The fracture toughness and bending strength of the composites have been greatly improved and the hardness is almost identical to that of Al2O3 matrix. Based on the first-principles density functional theory, the DOS for TiN and TiNx was calculated. The covalent bonding is weakened and the metallic bonding is strengthened as the nitrogen concentration is reduced in nonstoichiometric TiNx. The active slip systems determined by covalent bonding for the nitrides are possibly increased by adding nonstoichiometric TiN0.3, which improves the fracture toughness of Al2O3-based composites. Acknowledgments The authors gratefully acknowledge financial support from Key Laboratory of Metastable Materials Science and Technology, the Science and Technology Foundation of Hebei (E2012203116), the Key Item of Education Department of Hebei (ZH2012003), Synergy Innovation Plan Project of College of Mechanical Engineering (JX2014-3), and Heavy Machinery Synergy Innovation Plan Project (ZX01-20140100-01). References [1] Jingguo Li, Lian Gao, Jingkun Guo. Mechanical properties and electrical conductivity of TiN–Al2O3 nanocomposites. J. Eur. Ceram. Soc. 2003; 23: 74-6. [2] Songlin Ran, Lian Gao. Electrical properties and microstructural evolution of ZrO2–Al2O3–TiN nanocomposites prepared by spark plasma sintering. Ceram. Int. 2012; 38: 4928-6. [3] Bellosi A., Guicciardi S., Tampieri A.. Development and characterization of electroconductive Si3N4–TiN composites. J. Eur. Ceram. Soc. 1992; 9: 93-11. [4] Rak Z. S., Czechowski J.. Manufacture and properties of Al2O3–TiN particulate composites. J. Eur. Ceram. Soc. 1998; 18: 380-8. [5] Bellosi A., Portu G. D., Guicciardi S.. Preparation and properties of electroconductive Al2O3-based composites. J. Eur. Ceram. Soc. 1992; 10: 315-9. [6] Eric Laarz, Mats Carlsson, Benot Vivien, Mats Johnsson, Mats Nygren, Lennart Bergstrà ¶m. Colloidal processing of Al2O3-based composites reinforced with TiN and TiC particulates, whiskers and nanoparticles, J. Eur. Ceram. Soc. 2001; 21: 1035-9. [7] Z. J. Shen, M. Johnsson, M. Nygren. TiN/Al2O3 composites and graded laminates thereof consolidated by spark plasma sintering. J. Eur. Ceram. Soc. 2003; 23: 1068-8. [8] Y.H. Fei, C.Z. Huang, H.L. Liu, B. Zou. Mechanical properties of Al2O3–TiC–TiN ceramictoolmaterials. Ceram. Int. 2014; 40: 10209-5. [9] Zhijian Shen, Mats Johnsson, Mats Nygren. TiN/Al2O3 composites and graded laminates thereof consolidated by spark plasma sintering. J. Eur. Ceram. Soc. 2003; 23: 1068-8. [10]J. F. Sun, M. Z. Wangà ¯Ã‚ ¼Ã…’Y. C. Zhao, X. P. Li, B. Y. Liang. Synthesis of titanium nitride powders by reactive ball milling of titanium and urea. J. Alloys Compd. 2009; 482: L31-3. [11] Shuai Xu, MingzhiWang, LinaQiao, JianliBing, QinZou, YuchengZhao. Enhancing the sinteringability of TiNx by introduction of nitrogen vacancy defects. Ceram. Int. 41 (2015) 9514–9520. [12] A.S. Kurlov, A.I. Gusev. Effect of nonstoichiometry of NbCy and TaCy powders on their high–energy ball milling. Int. J. Refract. Met. Hard Mater. 2014; 46: 136-12. [13] A.S. Kurlov, A.I. Gusev. High–energy milling of nonstoichiometric carbides: Effect of nonstoichiometry on particle size of nanopowders. J. Alloys Compd. 2014; 582: 118-11. [14] M. Kirihara, A. Itou, T. Noguchi, J. Yamamoto. Tantalum carbide or niobium carbide catalyzed oxidation of sulfides with hydrogen peroxide: Highly efficient and chemoselective syntheses of sulfoxides and sulfones. Synlett 2010; 21: 1561-5. [15] M. Guemmaz, A. Mosser, J.-C. Parlebas. Electronic changes induced by vacancies on spectral and elastic properties of titanium carbides and nitrides. J. Electron. Spectrosc. Relat. Phenom. 2000; 107: 101-11. [16] I.Pollini , A.Mosser , J.C. Parlebasb. Electronic, spectroscopic and elastic properties of early transition metal compounds. Physics Reports 2001; 355: 1-72. [17] G.R. Anstis, P. Chantikul, B. R. Lawn, D. B. Marshall, Acritical evaluation of indentation techniques for measuring fracture toughness: I, direct crack measurements, J. Am. Ceram. Soc. 64 (9) (1981) 533–538. [18] Shen Z. J., Johnsson M., Zhao Z., Nygren M.. Spark plasma sintering of Al2O3. J. Am. Ceram. Soc. 2002; 85 (8): 1927-7. [19] Evans A. G., Charles E. A.. Fracture toughness determination by intentation. J. Am. Ceram. Soc. 1976; 59 (7-8): 372-2. [20] Egawa T., Ichikizaki T., Tsukamoto H., Tsunoda H., Shimoyama T.. Material characteristics and cutting performance of TiN–Al2O3 ceramic tool. Int. J. Jpn. Soc. Precis. Eng. 1995; 29 (3): 228-7. [21] Y. Yang, H. Lu, C. Yu, J.M. Chen. First-principles calculations of mechanical properties of TiC and TiN. J. Alloys Compd. 2009; 485: 547-6. [22] R. H. J. Hannink, D. L. Kohlstedt, M. J. Murray. Slip system determination in cubic carbides by hardness anisotropy. ProcRoy Soc. 1972; 326 A (1566): 420-12. Figure captions Fig. 1 X-ray diffraction patterns of Al2O3–30 vol% TiN0.3 composite sintered via SPS at different temperatures in vacuum (6Ãâ€"103 Pa) for 10 min. Fig. 2 Back-scattered SEM micrograph of polished surface of Al2O3–30 vol% TiN0.3 composite sintered via SPS at 1400  °C in vacuum (6Ãâ€"103 Pa) for 10 min. Fig. 3 SEM micrographs of fracture cross-sections of Al2O3–30 vol.% TiN0.3 composite sintered via SPS at different temperatures in vacuum (6Ãâ€"103 Pa) for 10 min: (a) 1300  °C; (b) 1400  °C; (c) 1500  °C; (d) 1600  °C. Fig. 4 SEM micrographs of fracture cross-sections of the composites sintered via SPS at 1400  °C in vacuum (6Ãâ€"103 Pa) for 10 min: (a) Al2O3–10 vol% TiN0.3; (b) Al2O3–20 vol% TiN0.3; (c) Al2O3–30 vol% TiN0.3; (d) Al2O3–40 vol% TiN0.3. Fig. 5 Vickers hardness and fracture toughness of (a) Al2O3–30 vol% TiN0.3 composite versus sintering temperature; (b) Al2O3–TiN0.3 composites sintered at 1400  °C versus TiN0.3 content. Fig. 6 Bending strength of Al2O3–TiN0.3 composites sintered at 1400  °C versus TiN0.3 content. Fig. 7 Density of states for TiN and TiNx. à ¯Ã‚ Ã¢â‚¬ ºÃƒ ¯Ã¢â€š ¬Ã‚ ªÃƒ ¯Ã‚ Ã‚  Corresponding author. Tel (fax): 086-0335-8061671; E-mail: [emailprotected] Supported by the Hebei Province Scientific Committee of China (Nos. E2012203116, ZH2012003, JX2014-3 and ZX01-20140100-01).

John Milton’s Paradise Lost as an Epic Poetry Essay

The epic poem has been regarded ion all ages and countries as the highest form of poetry and there are great epics in almost in all the literatures in the world. As Dr. Johnson has put it, â€Å"By the general consent of critics, the first praise of genius is due to the writer of an epic poem, as it requires an assemblage of all the powers which are singly sufficient for other compositions†¦ Epic poetry undertakes to teach the most important truths by the most pleasing precepts, and therefore, relates some great event in the most affecting manner† (xix). John Milton’s Paradise Lost belongs to a rare breed of epic poetry in that it conforms to all the structural aspects of an epic, much in contrast with the decline of epic in the eighteenth century (Griffin 143-154). In the eighteenth century, the epic conventions made a gradual shift to mock-heroic poetry – a literary form that pseudo-eulogizes events of stately stature, in a bid to satirize them. But Milton, an egotist throughout his life, picks up topics of profound significance in the context of Christianity, and writes in an epic style that is perfectly complemented by content and theme. This paper is going to analyze Paradise Lost as an epic poetry. Paradise Lost, which was originally published 1667 in 10 volumes, is written in blank verse – a literary device deployed to convey freedom of expression which is commonly attributed to poems of grand scope. The poem vividly narrates the story of Satan and the Fallen Angels. Man’s expulsion from God’s abode in heaven is the main theme addressed in the book. If one takes into consideration the binding principle of epic poetry as having some fundamental and simplest of storylines, Paradise Lost qualifies per se. the story of man giving in to temptation and his subsequent fall from divine grace is a recurring theme in many world literatures. Hence, its subject matter is of universal interest. Again, the story is told within a narrative framework which is fictional in nature. The narrative flow has plenty of drifts when the poet alludes to several biblical and pagan beliefs. But the allusions are very much in keeping with the central theme of the poem – to â€Å"justify the ways of God to men† (Milton, I. 26). Johnson’s views of an epic poem substantiate the thesis pretty well. Almost all the characteristic elements of an epic poem are present in Paradise Lost: The subject matter being dealt with ought to be of a grand scale, preferably some well known tales of heroism and/or defiance of convention. Normally, the subject of an epic is expected to deal with actual historical events or imaginary but probable tales.  The action of the story must be developed by a proportionate mix of grand narrative, dialog and soliloquy.  Meditative and dramatic elements abound in epic poetry. Hence, the canvas of an epic poetry is structured with minute attention to detail, having periodical digressions relevant to the progression of the storyline. The protagonist or the hero must not represent the institutional segment of society. In other words, his actions and words should reflect offbeat ideas intended to defy institutional norms. However, the hero should also possess moral transparency and lofty idealism. The story must be based on the hero.  The language and other literary techniques should be simple yet profound. One of the rudimentary aspects of epic poetry is that it should always be expressed in a free flowing form, stripped of excesses wherever feasible. At the same time, the language should never appear as if constrained by the plot. The plot and the narrative must complement each other without limiting the immense scope of each.  An epic should always propound a lofty moral, capable of standing on its own. in other words, an epic poem must have a generic message that stands true irrespective of times or ideological differences.   It may be noted that all the aforementioned elements can be found in Milton’s Paradise Lost. In addition to this, the poem also follows classical epic conventions such as invocation to the Muse, prolific usage of epic similes and metaphors, blank versification, repetition of lines and passages, permanent epithets and so on. The subject matter of Paradise Lost is common yet sublime. The very inclusion of a biblical theme sets the poem apart from ordinary tales of man’s temporal existence. The Fall of Man has a fatalistic attribution to it, which instantly encompasses everything ever created or to be created within Miltonic cosmos. Milton’s cosmology pertains to a profoundly sagacious vision of the heaven and the earth and how they make exchanges. Satan’s revolt against the Supreme Dictator lays down the premise for an epic rendering of mankind’s perpetual urge to go against norms that put chains on free will. In keeping with epic characteristics, the poem elicits sympathetic responses from readers and critics alike. On one hand, Adam and Eve are thrown out of heaven following their cardinal sin. The divine providence they would enjoy is no longer there. This puts in perspective the hierarchical notion of the order of beings – God at the helm of affairs followed by the list of created beings. What is of epic stature is that the lower hierarchy suddenly rebels against the highest, challenging the supreme authority in a dauntless manner. Their punishment is also a part of the development of an epic. Once they are booted off heaven, readers can almost sense that intangible attributes such as immortality and permanence are lost forever. What is born of defiance is what comes to be standing in the long run – man’s original happiness and restoration of peace and love in their reasonable forms. Once Satan and his men are taught a lesson, following the epic conventions, mortals no longer dare to put themselves in any fanciful longing guided by moral cogency. As far as action is concerned, Paradise Lost unitarily follows a single course of events – all culminating in a grand climax. Milton begins the story by describing the infernal council of the rebel angels, which precedes the Fall of Man. Aspects of epic poetry are rooted in the poet’s approach here. He does not intend to simply narrate the proceedings as they occur. He stamps his own persona by suggesting the mood for revelry the Fallen Angels are in. Thus, the storyline starts from a single point in time and advances from thereon. Nothing is left behind and nothing is to be seen or apprehended in advance. The battle of the angels and the creation of earth are events that follow from one another and do not occur discordantly. Invocation of the Muse, too, is a generic pattern commonly followed in epic poems (Poplawski 266). In essence, Milton’s Paradise Lost is typical of epic poetry in multiple regards. The way it deals with the subject matter, with linguistic mastery and in an introspective mood, goes to show the unique niche the poem still enjoys in literary domains worldwide. As an authentic piece of world literature, Paradise Lost excels over contemporary heroic poetry in many ways. Right from the outset, each character has particular relevance to the story and has generic relevance to the entirety of the historical framework the poem belongs to. Such flawless technique renders a stately charm to the poem.          Works Cited Griffin, Dustin. â€Å"Problems of Literary Theory.† New Literary History 14 (1982): 143-154. Milton, John. Paradise lost: a poem in twelve books. Cambridge, Massachusetts: Harvard University, 1868. Milton, John, Elijah Fenton, and Samuel Johnson. Paradise lost. Cambridge, Massachusetts: Harvard University, 1821. Poplawski, Paul. English Literature in context. New York: Cambridge University Press, 2007.

Juvenile Delinquency Essay

We hear a child stealing an apple from the market stands, and then rob a small shop, next day we learn about a 17-year-old kid who killed his classmates. People are concerned and rightly so. That’s all what we do or maybe give them a harsh punishment. It seems that the problem has only focused on punishment and very little on prevention or intervention. There is no single cause of violence but we can certainly list a lot of risk factors, which increase the development of criminal behaviour. These include child abuse and family disintegration, violating behavior, academic failure, school dropout, and lack of contact with the society, fighting with peers and antisocial behavior early in life. Juvenile crime rates have nearly doubled in many countries. In the news we keep hearing about youngsters got mixed up in shady affairs and committing petty crimes. What actually is a juvenile crime? Juvenile crime is a term denoting various offences committed by children or youths under the age of 18. Such acts are sometimes referred to as juvenile delinquency. Children’s offences typically include delinquent acts, which would be considered crimes if committed by adults, and status offences, which are less serious misbehavior problems such as truancy and parental disobedience. Both are within the jurisdiction of the youth court; more serious offences committed by minors may be tried in criminal court and be subject to prison sentences. In order to reveal the real background of juvenile crime it’s obviously not enough to stop at this point. Probably none of the young delinquents were born with hostility, rage and hatred. Their environment and our society have turned them into who they are today. Juveniles have to face the cruel sides of the world too early and they are not well prepared for it yet. Some of them are able to deal with it, some of them are not. The latter shocked by the realization will escape to the world of crimes so trying to hide themselves from all the dissatisfaction. Young people should not be expected to have the same values and judgment as adults, therefore not the same treatment either. This is especially true if they have been the victims of poverty, neglect, and abuse. The good approach of the problem can help a lot. Young lives can be salvaged but not with incarceration. It has never been a good solution. Nevertheless developing more programs’ to prevent these children entering the juvenile justice system would be far more effective and less costly.

Islam in Italy Essay - 2453 Words

Islam in Italy Problems with format Like many minority communities of varying religious and ethnic backgrounds, Muslims have struggled to define their place in societies around the world. As immigration patterns have ebbed and flowed through the centuries, Italy is one of many European countries that plays host to a growing number of Muslim immigrants.? Muslims struggle with identity, intermarriage, gender relations, worship, education, and civil rights in the context of their new country.? These issues are particularly poignant for Muslims entering and living within Italy during this religiously momentous time.? During the past twenty years, Italy has seen a resurgence of immigrants who hold to the Islamic tradition.? For the†¦show more content†¦Its effects were felt in commerce, language, and culture until Sicily was retaken by the Normans in 1091. Transition From the Dark Ages The main entrance to the city of Mazara del Vallo?s eleventh century cathedral depicts the Norman prince Roger I on horseback with sword in hand, personally chasing the last of the Muslims away from Sicily.? This not-so-subtle warning was added during the sixteenth century to honor Roger, who reclaimed Sicily after 200 years of Muslim rule (Holzner).? Hundreds of years later, Muslims are crossing back into Italy?s borders not as conquerors of the past, but as peasants, merchants, and workers who intend to stay in Europe to escape the economic stagnation and overpopulation of their countries of origin.? For many Muslims, Mazara del Vallo is the first stop before venturing north to Italy?s larger cities.? Yet those who do go north are welcomed by another symbol in distinct opposition to Roger I; Europe?s newest and largest mosque speaks volumes of Islam?s permanence in Italy. Contemporary Conditions The past two decades have brought a drastic change to Italy?s demographics, along with a change in the architecture, which now is comprised of domed roofs and minarets that pierce the skyline in even the most historically Catholic cities.? This phenomenon has impacted all aspects of Italian society: religious, social, occupational, educational, cultural, and institutional.Show MoreRelatedSimilarities Between Christianity And Islam942 Words   |  4 PagesChristianity and Islam are two of history’s most influential and powerful religions in the post-classical and early modern era. As different regions began to communicate, products, ideas, and services were exchanged across vast distances. Civilizations became less isolated and depended on other regions to sustain stable economies. The role of the merchant increased as trade arose with other regions. 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