MAGE Spectrometer for the Investigation of Hadron–Nucleus Interactions and the Identification of Final Nuclear States

A combined spectrometer is composed of a wide-aperture magnetic spectrometer with proportional chambers and a -spectrometer based on a Ge(Li) detector. The respective momentum and the angular resolutions of the magnetic spectrometer are FWHM/p(%) = 0.59p (GeV/c) + 1.1 and 0.5–1 mrad; its average efficiency for 0°–5° angles is 85%. The energy resolution of the -spectrometer is 8 and 16 keV for 0.5- and 2.0-MeV photons, respectively; the average angular acceptance is 1.5 msr.     

A 10-Gb/s laser/modulator driver IC with a dual-mode activelymatched output buffer

A laser/modulator driver IC for 10-Gb/s-SONET OC-192-fiber optic transmitters is described. Depending on the user application, the IC is capable of driving more than 100 mA of current into a laser diode or over 50 mA into an electro-absorption or Mach-Zehnder modulator. Rise and fall times below 20 pS are achieved. The driver employs a novel dual-mode actively matched output buffer that provides a dc-coupled back termination of either 25 or 50 Ω. Compared to an output buffer with a resistive termination, this buffer dissipates only half as much power. In addition, the buffer has the the ability to reject external bias and will therefore not load bias sources used to set laser threshold currents and modulator offset voltages. The low power consumption makes the IC most suitable for co-packaging with uncooled lasers and electro-absorption modulators. The driver is fabricated in a 0.25-μm gate length production GaAs PHEMT process with substrate thru vias, thin-film resistors, and MIM capacitors     

Speciation of radionuclides in colloidal matter of underground waters taken from observation wells in the zone of impact of Lake Karachai

The strength of actinide bonding with colloidal matter of groundwaters from the Lake Karachai contamination area was studied by selective leaching. An α-track analysis showed that the microdistribution of α-emitting radionuclides in the colloidal matter is uniform. Analysis of fission tracks confirms the presence of ²³⁹Pu and ²⁴¹Am in the colloidal material. In the colloidal matter of groundwaters taken from three wells and differing in the chemical composition, radionuclides occur in forms differing in the solubility. U and Np in the colloidal material are associated only with readily soluble and mobile groups of compounds and are not detected in the difficultly soluble residue. Pu and Am, on the contrary, occur in the colloidal material of groundwaters mainly in difficultly soluble forms. Am is bound to a greater extent with surface organometallic complexes. Pu is detected mainly in the fraction of amorphous oxides.     

Isolation of new brominated sesquiterpene feeding deterrents from tropical green algaNeomeris annulata (Dasycladaceae: Chlorophyta)

We investigated the natural products chemistry and feeding deterrent effects of brominated sesquiterpenes produced by Pacific collections of the calcareous tropical green algaNeomeris annulata. Assays conducted with whole algae showed thatN. annulata was not susceptible to grazing by natural populations of herbivorous fishes on Guam. Crude extracts and column chromatography fractions containing the brominated sesquiterpenes deterred feeding by herbivorous fishes at natural concentrations in field assays on Guam. Two majorN. annulata sesquiterpenes isolated from Guam collections and three related sesquiterpenes previously reported from Bermuda all deterred fish feeding at the high end of their natural concentration ranges, with the exception of one metabolite from Bermuda collections of the alga that differed structurally from the other compounds. The results support our hypothesis that the compounds produced byNeomeris function as chemical defenses against herbivores. The alga produces both structural defenses (CaCO₃ in the form of aragonite) and secondary metabolites that defend against herbivory by reef fishes.     

Evaluation of harassment of migrating double-crested cormorants to limit depredation on selected sport fisheries in Michigan

Diverse management techniques have been used to mitigate conflicts between humans and double-crested cormorants (Phalacrocorax auritus) including harassment methods supplemented by lethal take. In this study we evaluated impacts of programs to harass spring migrating cormorants on the walleye (Sander vitreus) fishery in Brevoort Lake and the yellow perch (Perca flavescens) and walleye fisheries at Drummond Island. Cormorant foraging declined significantly (p < 0.05) at both locations subsequent to initiation of harassment programs. Overall harassment deterred 90% of cormorant foraging attempts while taking less than 6% lethally on average at each site. Yellow perch were a predominate prey item in number and biomass at both locations. Walleye made up a small proportion of the diet at both locations. However, both walleye and yellow perch abundance increased significantly (p < 0.05) at Drummond Island. Walleye abundance at age 3 increased to record levels in 2008 following 3 years of cormorant management at Brevoort Lake. The estimated cormorant consumption of age-1 walleye in the absence of management at Brevoort Lake during 2005 would account for 55% of the record 2006 age-1 walleye population. These results support the hypothesis that cormorant predation on spawning aggregations of sportfish was a significant mortality factor and cormorant management reduced sportfish mortality and increased abundance at both locations. Continuation of harassment programs and fishery assessments will determine whether improvement of targeted sport fisheries through control of spring migrating cormorants is sustainable.     

Creeping flows in rectangular cavities with translating top and bottom walls: Numerical study and flow visualization

The recirculating flow patterns in the creeping flow range of an incompressible fluid in rec-tangular cavities with translating top and bottom walls were obtained numerically and by visualization, then were compared with each other. The aspect ratio was put to be either one or two. Approximate solutions were obtained for various boundary conditions by using the variational method The streamlines near the sharp corners were compared with some analytical solutions and the region in which the analytical solutions can safely be applied was confirmed.     

Phosphorous Levels in Peeled and Deveined Shrimp Treated with Sodium Tripolyphosphate

Using volumetric and spectrophotometric methods for the determination of phosphorous, untreated shrimp were shown to have high and variable phosphorous content. When peeled and deveined shrimp were treated with 0.5% and 1.0% sodium tripolyphosphate (STP) solutions, the STP uptake was shown to be low. At these low treatment concentrations the phosphorous content in the treated shrimp did not exceed the range of natural phosphorous found in untreated shrimp. When higher treatment concentrations were used, treated thrimp could be identified. The stability of STP in treated shrimp during frozen storage was investigated using a P³² STP isotope. After 2 wk of frozen storage at –26°C only 12% of the total activity could be attributed to STP. At the same time, pyrophosphate was present at a level of 25% and orthophosphate at 27%. During further frozen storage, the STP concentration remained at approxinately 12%, pyrophosphate dropped down to as low as 2% while orthophosphate gradually increased reaching 45% of total activity at the end of 10 wk storage period.     

Investigation and minimization of underfill delamination in flip chip packages

A generalized plane strain condition is assumed for an edge interfacial crack between die passivation and underfill on an organic substrate flip chip package. C4 solder bumps are explicitly modeled. Temperature excursions are treated as loading conditions. The design factors studied include underfill elastic modulus, underfill coefficient of thermal expansion (CTE), fillet height, and die overhang. Varying underfill modulus and CTE produces a different stress field at underfill/die passivation interface, different stress intensity factor (SIF), and phase angle (/spl psi/) even under the same loading condition. The baseline case uses underfill with elastic modulus of 6 GPa, CTE of 36 ppm//spl deg/C and fillet height equal to half die thickness. Four more cases involving underfill material properties are investigated by varying elastic modulus between 3 and 9 GPa, and by varying CTE between 26 and 46 ppm//spl deg/C. The effect of fillet height is also studied by assuming no fillet and full fillet, i.e., fillet height equal to die thickness. Finally, two cases concerning the influence of die overhang, defined as the nominal distance between outermost solder joint and die edge, are investigated. Fracture parameters, including energy release rate (G) and phase angle (/spl psi/), are evaluated as a function of dimensions. Underfill material properties (elastic modulus and CTE), fillet configuration, and die overhang can be optimized to reduce the risk of underfill delamination in flip chip or direct chip attach (DCA) applications.