First record of the Spiny blaasop Tylerius spinosissimus (Regan, 1908) (Tetraodontidae) from the Turkish coasts

The non-indigenous tetraodontid of Indo-Pacific origin Tylerius spinosissimus is recorded for the first time in Turkish waters and for the third time in the Mediterranean Sea. This record increases to 53 the number of Indo-Pacific alien fish species present along the coasts of Turkey

Identificación poblacional de sepia (Sepia officinalis) en Mediterráneo NE inferido a partir de datos genéticos, morfométricos y químicos del sepión

The population structures of the common cuttlefish Sepia officinalis from the north-eastern Mediterranean (Antalya and Iskenderun Bays), Aegean (Izmir Bay) and Marmara Seas were analyzed with mtDNA PCR-RFLP, body morphometry and cuttlebone chemistry. Analysis of a ND 5/6 (Nikotin Amid Adenin Dehidrojenaz-5/6) gene segment of mtDNA revealed seven haplotypes from 120 individuals. No haplotype sharing was observed among sampling sites. The average nucleotide divergence between samples was 0.009390, and the highest genetic divergence (0.015279) was observed between the Iskenderun Bay and Marmara Sea samples. The lowest genetic divergence (0.003786) was between the Aegean Sea and Antalya Bay samples. Highly significant differences (PLa estructura poblacional de la sepia común del Mediterráneo noreste (bahías de Antalya y de Iskenderun), Mar Egeo (Bahía de Izmir) y Mar de Mármara ha sido analizada mediante la técnica de PCR-RFLP del ADNmitocondrial (mtDNA), la morfometría del cuerpo y química del sepión. El análisis de variabilidad de secuencia de un fragmento del gen mitocondrial ND 5/6 (Nikotin Amid Adenin Dehidrojenaz-5/6) de 120 individuos reveló siete haplotipos distintos. Ninguno de ellos compartido entre localidades. La divergencia nucleotídica media entre muestras es de 0.009390, con el máximo valor de divergencia genética (0.015279) observado entre las localidades de la bahía Iskenderun y el Mar de Mármara, y el mínimo valor de divergencia genética (0.003786) entre las localidades del mar Egeo y la bahía de Antalya. Los análisis basados en las simulaciones de Monte Carlo y AMOVA mostraron diferencias altamente significativas (P<0.001) entre todas las localidades. En el árbol filogenético de UPGMA, las localidades colindantes de Antalya y de Mar Egeo se agrupan en la misma rama. Por otro lado, las localidades más aisladas, Mar de Mármara y bahía de Iskenderun, se distribuyen en los clados más divergentes. En el análisis de la función discriminante, la clasificación de las tasas de éxito en la asignación de especímenes a las regiones fue 66% para el análisis morfométrico y un 100% para la química del sepión. En el análisis morfométrico solamente se detectaron diferencias significativas entre las muestras del Mar de Mármara y la bahía de Iskenderun, mientras que el resto de localidades se agrupan entre ellas. En el análisis de la química del sepión, el análisis univariante ha revelado diferencias altamente significativas (P<0.001) entre todas las regiones en 12 elementos Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Pb, Zn. En el análisis multivariante se observan diferencias altamente significativas (P<0.001) entre las cuatro localidades. Este estudio muestra la presencia de cuatro poblaciones separadas de S. officinalis a lo largo de las aguas de la costa turca

Carbon nanotube based electromechanical probes

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.Includes bibliographical references (p. 131-137).Electromechanical probing applications continuously require smaller pitches, faster manufacturing and lower electrical resistance. Conventional techniques, such as MEMS based cantilever probes have their shortcomings in terms of the lowest pitch that can be achieved, cost and yield. Given their promising mechanical and electrical properties, carbon nanotubes (CNTs) are strong candidates for future probing applications. A new class of metal-CNT hybrid electromechanical probes is presented where vertically aligned carbon nanotube structures, grown with a chemical vapor deposition (CVD) technique, act as elastic springs, and a metal coating on the probes is used for increased electrical conduction. This design and architecture presents a scalable approach where thousands of probes can be fabricated in very short production times. 1.5 Ohm resistance and reliable performance for 6000 cycles at 50 [mu]m over-travel was achieved for a column of 200 [mu]m x 200[mu]m cross-section and 1plm of Au deposition. In-situ scanning electron microscope mechanical compression tests revealed a unique deformation mechanism of the CNT structures where continued compression results in successive buckle formation which later can serve as micro-bellows and elastic springs.(cont.) A novel stiffness tuning method is presented to control the elastic properties of a given CNT probe by controlling the initial compressing amount. Further stiffness tuning is achieved by changing gas composition during CVD growth where CNT diameter and density is modified. Lateral compression and densification tests show that these CNT structures are highly anisotropic and have very different deformation mechanisms in vertical and lateral directions. Mechanical properties resulting from two main CVD growth techniques, namely fixed catalyst where a thin film of catalyst layer is deposited onto the growth substrate, and floating catalyst where the catalyst particles are introduced in the gas phase, are compared. It is found that floating catalyst CVD growth yields much stiffer structures due to the relatively larger CNT diameters. As the adhesion of CNT structures to the growth substrate is very weak and the support layer is typically an insulator, a versatile transfer printing technique is developed which enables simultaneous placement and reinforcement of the probes on a wide range of substrates, including metals and printed circuit boards. Electromechanical performance and failure mechanisms of fully functional metal-CNT hybrid probes are presented.by Onnik Yaglioglu.Ph.D

Modeling and design considerations for a micro-hydraulic piezoelectric power generator

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2002.Includes bibliographical references (p. 165-170).Piezoelectric Micro-Hydraulic Transducers are compact high power density transducers, which can function bi-directionally as actuators/micropumps and/or power generators. They are designed to generate 0.5-1W power at frequencies of ~10-20kHz, resulting in high power densities approaching 500W/kg. These devices are comprised of a main chamber, two actively controlled valves, a low-pressure reservoir and a high-pressure reservoir. This thesis reports on modeling and design considerations for Micro-Hydraulic Piezoelectric Power Generators. Since these devices are complex fluid and structural systems, comprehensive simulation tools are needed for effective design. Operation of each subcomponent of the device is highly coupled and every design decision should be made with remaining components in mind. A system level simulation tool has been developed using Matlab/Simulink, by integrating models for different energy domains, namely fluids, structures, piezoelectrics and circuitry. The simulation architecture allows for integration of the elastic equations of structural members into the dynamic simulations as well as monitoring of important parameters such as chamber pressure, flowrate, and various structural component deflections and stresses. Using the simulation, the operation of the system is analyzed and important design considerations are evaluated. Fluidic oscillations within the system are analyzed and an optimization procedure for the membrane structure within the main chamber is presented. Parameter studies are performed for different piezoelectric materials, system compliances, and circuit topologies. Tradeoffs between operation conditions and their effect on the performance are discussed. A design procedure is developed. Results indicate that system efficiency is highly dependent on compliances within the device structure, the type of piezoelectric material used and rectifier circuit topology.by Onnik Yaglioglu.S.M

Femtosecond laser crystallization of amorphous Ge

Cataloged from PDF version of article.Ultrafast crystallization of amorphous germanium (a-Ge) in ambient has been studied. Plasma enhanced chemical vapor deposition grown a-Ge was irradiated with single femtosecond laser pulses of various durations with a range of fluences from below melting to above ablation threshold. Extensive use of Raman scattering has been employed to determine post solidification features aided by scanning electron microscopy and atomic force microscopy measurements. Linewidth of the Ge optic phonon at 300 cm(-1) as a function of laser fluence provides a signature for the crystallization of a-Ge. Various crystallization regimes including nanostructures in the form of nanospheres have been identified. (C) 2011 American Institute of Physics. [doi:10.1063/1.3601356

First record of the broad-banded cardinal fish Apogon fasciatus (White, 1790) from Turkey

Two specimens of the alien cardinal fish Apogon fasciatus (White, 1790) are recorded for the first time from Turkey and second time from the Mediterranean Sea. This is the fourth Indo-Pacific apogonid species documented in the Mediterranean Sea, and the introduction of this species to the eastern Mediterranean is due to migration from the Red Sea via the Suez Canal

Crystallization of Ge in SiO2 matrix by femtosecond laser processing

Cataloged from PDF version of article.Germanium nanocrystals embedded in a siliconoxide matrix has been fabricated by single femtosecond laser pulse irradiation of germanium doped SiO2 thin films deposited with plasma enhanced chemical vapor deposition. SEM and AFM are used to analyze surface modification induced by laser irradiation. Crystallization of Ge in the oxide matrix is monitored with the optic phonon at 300 cm(-1) as a function of laser fluence. Both the position the linewidth of the phonon provides clear signature for crystallization of Ge. In PL experiments, strong luminescence around 600 nm has been observed. (C) 2012 American Vacuum Society. [DOI: 10.1116/1.3677829

Wide Range Control of Microstructure and Mechanical Properties of Carbon Nanotube Forests: A Comparison Between Fixed and Floating Catalyst CVD Techniques

Vertically aligned carbon nanotube (CNT) forests may be used as miniature springs, compliant thermal interfaces, and shock absorbers, and for these and other applications it is vital to understand how to engineer their mechanical properties. Herein is investigated how the diameter and packing density within CNT forests govern their deformation behavior, structural stiffness, and elastic energy absorption properties. The mechanical behavior of low‐density CNT forests grown by fixed catalyst CVD methods and high‐density CNT forests grown by a floating catalyst CVD method are studied by in situ SEM compression testing and tribometer measurements of force‐displacement relationships. Low‐density and small‐diameter CNT columns (fixed catalyst) exhibit large plastic deformation and can be pre‐deformed to act as springs within a specified elastic range, whereas high‐density and large‐diameter CNT columns (floating catalyst) exhibit significant elastic recovery after deformation. In this work the energy absorption capacity of CNT forests is tuned over three orders of magnitude and it is shown that CNT forest density can be tuned over a range of conventional foam materials, but corresponding stiffness is ∼10× higher. It is proposed that the elastic behavior of CNT forests is analogous to open‐cell foams and a simple model is presented. It is also shown that this model can be useful as a first‐order design tool to establish design guidelines for the mechanical properties of CNT forests and selection of the appropriate synthesis method. Wide range stiffness tuning of carbon nanotube (CNT) forests over three orders of magnitude is presented by directly modifying the diameter and packing density of CNTs through the modulation of chemical vapor deposition (CVD) parameters. Fixed catalyst and floating catalyst CVD techniques exhibit significantly different deformation mechanisms and the open‐cell foam model predicts the stiffness ratio within one type of CVD method very well.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94517/1/5028_ftp.pd

A piezoelectric microvalve for compact high frequency high differential pressure micropumping systems

A piezoelectrically driven hydraulic amplification microvalve for use in compact high-performance hydraulic pumping systems was designed, fabricated, and experimentally characterized. High-frequency, high-force actuation capabilities were enabled through the incorporation of bulk piezoelectric material elements beneath a micromachined annular tethered-piston structure. Large valve stroke at the microscale was achieved with an hydraulic amplification mechanism that amplified (40/spl times/-50/spl times/) the limited stroke of the piezoelectric material into a significantly larger motion of a micromachined valve membrane with attached valve cap. These design features enabled the valve to meet simultaneously a set of high frequency (/spl ges/1 kHz), high pressure(/spl ges/300 kPa), and large stroke (20-30 /spl mu/m) requirements not previously satisfied by other hydraulic flow regulation microvalves. This paper details the design, modeling, fabrication, assembly, and experimental characterization of this valve device. Fabrication challenges are detailed

Probing ultrafast energy transfer between excitons and plasmons in the ultrastrong coupling regime

Cataloged from PDF version of article.We investigate ultrafast energy transfer between excitons and plasmons in ensembles of core-shell type nanoparticles consisting of metal core covered with a concentric thin J-aggregate (JA) shell. The high electric field localization by the Ag nanoprisms and the high oscillator strength of the JAs allow us to probe this interaction in the ultrastrong plasmon-exciton coupling regime. Linear and nonlinear optical properties of the coupled system have been measured using transient absorption spectroscopy revealing that the hybrid system shows half-plasmonic and half-excitonic properties. The tunability of the nanoprism plasmon resonance provides a flexible platform to study the dynamics of the hybrid state in a broad range of wavelengths. (C) 2014 AIP Publishing LLC