Ballistic Performance of Alumina and Zirconia-toughened Alumina Against 7.62 Armour Piercing Projectile

A study was carried out to compare the ballistic performance of high purity alumina and zirconia-toughened alumina (ZTA) using depth of penetration (DoP) test configuration against 7.62 mm armour piercing (AP) ammunition. The effect of tile thickness on the differential efficiency factor (DEF) was studied for tile thickness in the range of 3 mm to 6 mm for alumina tiles and 3 mm to 5 mm for ZTA tiles. The DEF is found to increase as tile thickness increases. An analysis on the failed shots showed that the residual shot weight does not follow a single linear relationship with ceramic tile thickness unlike the residual DoP for all thicknesses of tiles. Post-ballistic analysis on ceramic powder for particle size distribution was carried out and the results are presented.Defence Science Journal, Vol. 64, No. 5, September 2014, pp.477-483, DOI:http://dx.doi.org/10.14429/dsj.64.674

Toughening and creep in multiphase intermetallics through microstructural control

The lack of engineering ductility in intermetallics has limited their structural applications, in spite of their attractive specific properties at high temperatures. Over the last decade, research in intermetallics has been stimulated by the discovery of remarkable ductilisation mechanisms in these materials. It has however often been the case that the process of ductilisation or toughening has also led to a decrease in high temperature properties, especially creep. In this paper we describe approaches to the ductilisation of two different classes of intermetallic alloys through alloying to introduce beneficial, second phase effects. The Ti2AlNb based intermetallics in the Ti-Al-Nb system can be ductilised by stabilising thebcc phase of titanium into the structure. The principles of microstructural and compositional optimization developed to achieve adequate plasticity, while retaining creep properties of these alloys, are described. An entirely different approach has been successful in imparting plasticity to intermetallics based on Fe3Al. The addition of carbon to form the Fe3AlC0.5 phase imparts ductility, while enhancing both tensile and creep strength

Klinisch-rechtsmedizinische Kompetenz in der Gewaltopferambulanz am Beispiel des Instituts für Rechtsmedizin Münster:eine retrospektive Studie aus den Untersuchungen des Instituts der Jahre 2006 bis 2013

In dieser Arbeit wurden 617 Untersuchungen, die in den Jahren 2006 bis 2013 im Institut für Rechtsmedizin der WWU Münster erfolgten, retrospektiv ausgewertet. Es handelte sich um klinisch-rechtsmedizinische Untersuchungen von Kindern, Jugendlichen und Frauen, bei denen den Tatvorwürfen der körperlichen und sexuellen Gewalt nachgegangen wurde. Der Schwerpunkt der Arbeit lag auf der Analyse der Verletzungsmuster der Opfer mit dem Ziel die Merkmale der verschiedenen Misshandlungsarten auszuarbeiten. Sowohl bei Frauen als auch bei Kindern bzw. Jugendlichen erweist es sich vor allem bei sexueller Gewalt als schwierig die erhobenenen Befunde einzuschätzen, da diese oft nicht eindeutig und aussagekräftig genug sind. Insgesamt lässt sich schlussfolgern, dass eine frühzeitige Untersuchung des Opfers eine bessere und umfangreichere Befundsicherung und Beurteilung zulässt. Zudem sollte eine standardisierte Anamnese und Untersuchung mithilfe von Erhebungsbögen erfolgen, sodass die Daten vollständig erhoben werden

Counting reducible, powerful, and relatively irreducible multivariate polynomials over finite fields

We present counting methods for some special classes of multivariate polynomials over a finite field, namely the reducible ones, the s-powerful ones (divisible by the s-th power of a nonconstant polynomial), and the relatively irreducible ones (irreducible but reducible over an extension field). One approach employs generating functions, another one uses a combinatorial method. They yield exact formulas and approximations with relative errors that essentially decrease exponentially in the input size.Comment: to appear in SIAM Journal on Discrete Mathematic

Comparative study between proximal femoral nail and proximal femoral nail antirotation in management of unstable trochanteric fractures

Background: In the management of peri-trochanteric fractures, intramedullary (IM) devices have proven advantage over extramedullary devices. IM devices allow for stable anatomical fixation of more comminuted fractures without shortening the abductor lever arm or changing the proximal femoral anatomy. Between IM devices like proximal femoral nail (PFN) and proximal femoral nail antirotation (PFNA), the helical blade of latter is believed to provide stability, compression and rotational control of the fracture with higher cut out strength. The following study was undertaken in an attempt to compare these two types of Intra-medullary devices.Methods: Between January 2012 and June 2013, 50 patients with unstable intertrochanteric fractures fulfilling inclusion and exclusion criteria, were randomized into 2 groups to undergo CRIF with either standard PFN (n=25) or PFNA (n=25). They were compared in terms of demography, per-operative variables and postoperative parameters including functional evaluation till 1year postoperatively.Results: Background demographic variables, fracture type and pre-injury ambulatory status were comparable between the groups. Operative duration of surgery, amount of blood loss and number of fluoroscopic images were significantly lower in PFNA group as compared to PFN group. Post op complications like infection, non-union, cut out/z-effect, loss of reduction, re-operation and mortality rates didn’t differ significantly between the groups. Post op functional recovery as evaluated by pain, use of walking aids and Harris hip scores were similar in both groups. Conclusions: PFNA significantly reduces the operative time, amount of blood loss and fluoroscopic imaging as compared to PFN. However PFNA offers no significant benefits over PFN in terms of post-operative functional recovery or complications

Raman Scattering Study of Ba-doped C60 with t1g States

Raman spectra are reported for Ba doped fullerides, BaxC60(x=3,4,and 6). The lowest frequency Hg modes split into five components for Ba4C60 and Ba6C60 even at room temperature, allowing us a quantitative analysis based on the electron-phonon couping theory. For the superconducting Ba4C60, the density of states at the Fermi energy was derived as 7 eV-1, while the total value of electron-phonon coupling \lambda was found to be 1.0, which is comparable to that of K3C60. The tangential Ag(2) mode, which is known as a sensitive probe for the degree of charge transfer on C60 molecule, shows a remarkable shift depending on the Ba concentration, being roughly consistent with the full charge transfer from Ba to C60. An effect of hybridization between Ba and C60 \pi orbitals is also discussed.Comment: 15 pages, 6 figures submitted to Phys. Rev. B (December 1,1998

Ferromagnetism and giant magnetoresistance in the rare earth fullerides Eu6-xSrxC60

We have studied crystal structure, magnetism and electric transport properties of a europium fulleride Eu6C60 and its Sr-substituted compounds, Eu6-xSrxC60. They have a bcc structure, which is an isostructure of other M6C60 (M represents an alkali atom or an alkaline earth atom). Magnetic measurements revealed that magnetic moment is ascribed to the divalent europium atom with S = 7/2 spin, and a ferromagnetic transition was observed at TC = 10 - 14 K. In Eu6C60, we also confirm the ferromagnetic transition by heat capacity measurement. The striking feature in Eu6-xSrxC60} is very large negative magnetoresistance at low temperature; the resistivity ratio \rho(H = 9 T)/\rho(H = 0 T) reaches almost 10^{-3} at 1 K in Eu6C60. Such large magnetoresistance is the manifestation of a strong pi-f interaction between conduction carriers on C60 and 4f electrons of Eu.Comment: 5 pages, 4 figure

Lifestyle travellers: Backpacking as a way of life

Scholarship on backpackers speculates some individuals may extend backpacking to a way of life. This article empirically explores this proposition using lifestyle consumption as its framing concept and conceptualises individuals who style their lives around the enduring practice of backpacking as ‘lifestyle travellers’. Ethnographic interviews with lifestyle travellers in India and Thailand offer an emic account of the practices, ideologies and social identity that characterise lifestyle travel as a distinctive subtype within backpacking. Departing from the drifter construct, which (re)constitutes this identity as socially deviant, the concept of lifestyle allows for a contemporary appraisal of these individuals’ patterns of meaningful consumption and wider insights into how ongoing mobility can lead to different ways of understanding identities and relating to place. Keywords: lifestyle consumption; backpacker; mobility; drifter; identit