A study of the stress wave factor technique for evaluation of composite materials

The acousto-ultrasonic approach for nondestructive evaluation provides a measurement procedure for quantifying the integrated effect of globally distributed damage characteristic of fiber reinforced composite materials. The evaluation procedure provides a stress wave factor that correlates closely with several material performance parameters. The procedure was investigated for a variety of materials including advanced composites, hybrid structure bonds, adhesive bonds, wood products, and wire rope. The research program focused primarily on development of fundamental understanding and applications advancements of acousto-ultrasonics for materials characterization. This involves characterization of materials for which detection, location, and identification of imperfections cannot at present be analyzed satisfactorily with mechanical performance prediction models. In addition to presenting definitive studies on application potentials, the understanding of the acousto-ultrasonic method as applied to advanced composites is reviewed

PCR for the detection of pathogens in neonatal early onset sepsis.

BACKGROUND: A large proportion of neonates are treated for presumed bacterial sepsis with broad spectrum antibiotics even though their blood cultures subsequently show no growth. This study aimed to investigate PCR-based methods to identify pathogens not detected by conventional culture. METHODS: Whole blood samples of 208 neonates with suspected early onset sepsis were tested using a panel of multiplexed bacterial PCRs targeting Streptococcus pneumoniae, Streptococcus agalactiae (GBS), Staphylococcus aureus, Streptococcus pyogenes (GAS), Enterobacteriaceae, Enterococcus faecalis, Enterococcus faecium, Ureaplasma parvum, Ureaplasma urealyticum, Mycoplasma hominis and Mycoplasma genitalium, a 16S rRNA gene broad-range PCR and a multiplexed PCR for Candida spp. RESULTS: Two-hundred and eight samples were processed. In five of those samples, organisms were detected by conventional culture; all of those were also identified by PCR. PCR detected bacteria in 91 (45%) of the 203 samples that did not show bacterial growth in culture. S. aureus, Enterobacteriaceae and S. pneumoniae were the most frequently detected pathogens. A higher bacterial load detected by PCR was correlated positively with the number of clinical signs at presentation. CONCLUSION: Real-time PCR has the potential to be a valuable additional tool for the diagnosis of neonatal sepsis

Metal-insulator transition in three dimensional Anderson model: universal scaling of higher Lyapunov exponents

Numerical studies of the Anderson transition are based on the finite-size scaling analysis of the smallest positive Lyapunov exponent. We prove numerically that the same scaling holds also for higher Lyapunov exponents. This scaling supports the hypothesis of the one-parameter scaling of the conductance distribution. From the collected numerical data for quasi one dimensional systems up to the system size 24 x 24 x infinity we found the critical disorder 16.50 < Wc < 16.53 and the critical exponent 1.50 < \nu < 1.54. Finite-size effects and the role of irrelevant scaling parameters are discussed.Comment: 4 pages, 2 figure

The use of Sponge Crude Extract to Increase Growth and Immune Response of Nile Tilapia Oreochromis niloticus

This study aims to examine the effect of sponge crude extract addition to the fish feed on growth and non-specific immune response of nile tilapia (O. niloticus) and determine the most effective dose of the extract in raising the growth and the non-specific immune response of nile tilapia (O. niloticus). The sponge sample was macerated and then evaporated using a rotary vacuum evaporator until the sample became a paste and mixed with feed. The fish were fed for 14 days respectively as much as 5% of body weight per day with feeding frequency of two times a day. The results showed that addition of sponge crude extract to the fish feed gave good effect on the growth and the non-specific immune response of nile tilapia (O. niloticus) with best dose of  40 g / kg feed.Keywords: Sponge extract, fish immune response, fish growth, immune response, immunostimulant. ABSTRAKPenelitian ini bertujuan untuk menguji pengaruh penambahan ekstrak kasar spons pada pakan ikan terhadap pertumbuhan dan respon imun  non spesifik ikan nila (Oreochromis niloticus) serta menentukan dosis ekstrak kasar spons yang paling efektif dalam meningkatkan pertumbuhan dan respon imun non spesifik ikan nila (Oreochromis niloticus). Sampel spons dimaserasi kemudian dievaporasi menggunakan rotary vacuum evaporator sehingga diperoleh ekstrak kasar berbentuk pasta yang kemudian dicampurkan pada pakan. Ikan uji diberi pakan perlakuan 5% dari bobot biomassa selama 14 hari dengan frekuensi pemberian pakan dua kali sehari. Hasil penelitian menunjukan bahwa penambahan ekstrak kasar spons pada pakan ikan memberikan pengaruh yang baik terhadap pertumbuhan dan respon imun non spesifik ikan nila (Oreochromis niloticus), yang mana dosis yang terbaik adalah 40 gr / Kg pakan.Kata Kunci : Ekstrak spons, respon imun ikan, pertumbuhan ikan, respon imun, imunostimulan

Anderson transitions in three-dimensional disordered systems with randomly varying magnetic flux

The Anderson transition in three dimensions in a randomly varying magnetic flux is investigated in detail by means of the transfer matrix method with high accuracy. Both, systems with and without an additional random scalar potential are considered. We find a critical exponent of $\nu=1.45\pm0.09$ with random scalar potential. Without it, $\nu$ is smaller but increases with the system size and extrapolates within the error bars to a value close to the above. The present results support the conventional classification of universality classes due to symmetry.Comment: 4 pages, 2 figures, to appear in Phys. Rev.

Йосиф Конрадович Пачоський: історіографія проблеми

Проаналізовано наукові, науково-популярні, публіцистичні, літературні джерела щодо біографії і наукової діяльності Й.К. Почоського, розділені на три періоди: перший — дореволюційний період вивчення життєвого шляху та наукової діяльності вченого (1882—1917), другий — радянський (1917—1989), третій — сучасний (1989 р.). Окрім вітчизняних, висвітлено праці дослідників із Польщі.Проанализированы научные, научно-популярные, публицистические, литературные источники по биографии и научной деятельности И.К.Пачоского, разделенные на три периода: первый — дореволюционный период изучения жизненного пути и научной деятельности ученого (1882—1917), второй советский (1917—1989), третий — современный (с 1989 г. ). Кроме отечественных, освещены работы исследователей из Польши.The paper contains analysis of scientific, popular-scientific, publicistic and literary sources on the scientific biography of I.K. Pachosky, divided in the three periods: first — pre-revolutionary (1882—1917), second — soviet (1917—1989), third — contemporary (1989 and on). Apart from national scientists, works of scientists from Poland also included

Phase diagram of localization in a magnetic field

The phase diagram of localization is numerically calculated for a three-dimensional disordered system in the presence of a magnetic field using the Peierls substitution. The mobility edge trajectory shifts in the energy-disorder space when increasing the field. In the band center, localized states near the phase boundary become delocalized. The obtained field dependence of the critical disorder is in agreement with a power law behavior expected from scaling theory. Close to the tail of the band the magnetic field causes localization of extended states.Comment: 4 pages, RevTeX, 3 PS-figures (4 extra references are included, minor additions), to appear in Phys. Rev. B as a Brief Repor

Anderson transition in three-dimensional disordered systems with symplectic symmetry

The Anderson transition in a 3D system with symplectic symmetry is investigated numerically. From a one-parameter scaling analysis the critical exponent $\nu$ of the localization length is extracted and estimated to be $\nu = 1.3 \pm 0.2$. The level statistics at the critical point are also analyzed and shown to be scale independent. The form of the energy level spacing distribution $P(s)$ at the critical point is found to be different from that for the orthogonal ensemble suggesting that the breaking of spin rotation symmetry is relevant at the critical point.Comment: 4 pages, revtex, to appear in Physical Review Letters. 3 figures available on request either by fax or normal mail from [email protected] or [email protected]

Anomalous diffusion at the Anderson transitions

Diffusion of electrons in three dimensional disordered systems is investigated numerically for all the three universality classes, namely, orthogonal, unitary and symplectic ensembles. The second moment of the wave packet $$ at the Anderson transition is shown to behave as $\sim t^a (a\approx 2/3)$. From the temporal autocorrelation function $C(t)$, the fractal dimension $D_2$ is deduced, which is almost half the value of space dimension for all the universality classes.Comment: Revtex, 2 figures, to appear in J. Phys. Soc. Jpn.(1997) Fe

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