801 research outputs found
Identification of a gene from Neurospora crassa with similarity to a glucoamylase gene from Schwanniomyces occidentalis
Glucoamylases are important industrial enzymes used in the conversion of starches to syrups and in other fermentation processes. Previously, the gene encoding the major glucoamylase activity of N. crassa was characterized (Stone et al. 1993 Curr. Genet 24:205-211). Here we report the identification of a possible second glucoamylase (gla-2) that is similar to a member of a class of glucoamylases represented by the GAM1gene of S. occidentalis (Dohmen et al. 1990 Gene 95:111-121)
A free-piston Stirling engine/linear alternator controls and load interaction test facility
A test facility at LeRC was assembled for evaluating free-piston Stirling engine/linear alternator control options, and interaction with various electrical loads. This facility is based on a 'SPIKE' engine/alternator. The engine/alternator, a multi-purpose load system, a digital computer based load and facility control, and a data acquisition system with both steady-periodic and transient capability are described. Preliminary steady-periodic results are included for several operating modes of a digital AC parasitic load control. Preliminary results on the transient response to switching a resistive AC user load are discussed
Test results of a Stirling engine utilizing heat exchanger modules with an integral heat pipe
The Heat Pipe Stirling Engine (HP-1000), a free-piston Stirling engine incorporating three heat exchanger modules, each having a sodium filled heat pipe, has been tested at the NASA-Lewis Research Center as part of the Civil Space Technology Initiative (CSTI). The heat exchanger modules were designed to reduce the number of potential flow leak paths in the heat exchanger assembly and incorporate a heat pipe as the link between the heat source and the engine. An existing RE-1000 free-piston Stirling engine was modified to operate using the heat exchanger modules. This paper describes heat exchanger module and engine performance during baseline testing. Condenser temperature profiles, brake power, and efficiency are presented and discussed
Single-Setting Bilateral Hand-Assisted Laparoscopic Partial Nephrectomy
Abstract Purpose: To assess the feasibility and safety of single-setting bilateral hand-assisted laparoscopic partial nephrectomy. Materials and Methods: Between August 2003 and June 2004, we performed single-setting bilateral laparoscopic partial nephrectomies on three patients. A hand-assisted approach was used, employing the same hand-assistance incision for both sides. Renal hilar clamping was not required, as the depth of penetration of all six tumors was only 0 to 4mm (mean, 1.8mm). The tumor diameters ranged from 1.8 to 3.8cm (mean, 2.4cm). Results: All operations were performed successfully, with no conversion to open surgery. Excision was performed with bipolar forceps, and final hemostasis was obtained with an argon beam coagulator (Valleylab, Boulder, CO) and Floseal (Baxter, Deerfield, IL), without suturing. The mean estimated blood loss was 208mL. The mean operative time was 246 minutes, which included repositioning. There were no intraoperative complications, and the postoperative course was uneventful in all patients except for a hospital stay of 5 days in one patient owing to transient ileus. Pathology revealed a benign lesion on one side and renal cell carcinoma on the other side in two patients, and bilateral leiomyomas in one patient. All margins of resection were negative, and neither of the two patients with cancer has had recurrence at a mean follow-up of 51 months. Among all three patients, the mean preoperative serum creatinine was 0.9mg/dL, and the average level at a mean of 35 months postoperatively was 1.0mg/dL. Conclusion: Single-setting bilateral hand-assisted laparoscopic partial nephrectomies can be safely and effectively performed on patients with bilateral small exophytic kidney tumors. We do not recommend this technique if both kidneys require temporary hilar occlusion, but it can be considered if only one kidney requires hilar occlusion.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78122/1/end.2008.0549.pd
Update on results of SPRE testing at NASA Lewis
The Space Power Research Engine (SPRE), a free-piston Stirling engine with a linear alternator, is being tested at NASA Lewis Research Center as part of the Civilian Space Technology Initiative (CSTI) as a candidate for high capacity space power. Results are presented from recent SPRE tests designed to investigated the effects of variation in the displacer seal clearance and piston centering port area on engine performance and dynamics. The impact of these variations on PV power and efficiency are presented. Comparisons of the displacer seal clearance tests results with HFAST code predictions show good agreement for PV power, but show poor agreement for PV efficiency. Correlations are presented relating the piston midstroke position to the dynamic Delta P across the piston and the centering port area. Test results indicate that a modest improvement in PV power and efficiency may be realized with a reduction in piston centering port area
Photo-reduced route of polyaniline nanofiber synthesis with embedded silver nanoparticles
AbstractThis work presents a method on the preparation and performance of four silver (Ag) concentrations in polyaniline (PANI) and polyvinyl alcohol (PVA) nanocomposite blend (PNPAg). The synthesis of Ag nanoparticles is first performed by photo reduction and then aniline is polymerized in Ag-PVA matrix. Morphological analysis by SEM and TEM reveals formation of nanoparticles with diameter 30–70nm. Nanocomposites with lower Ag concentrations have highly aligned PNPAg nanofibers of diameter 50–80nm and agglomeration for the one with higher concentrations. In addition, FTIR spectra show a systematic change in its characteristic peaks with increase in Ag contents. The crystallinity study depicts the tetragonal crystal structure of metallic nanocomposites having same particle sizes as obtained in SEM and TEM. In order to explore the possible applications of these nanocomposites in electronic industry, their electrical properties are investigated. The in-plane I-V characteristics indicate a transition of polymer nanocomposites from non-ohmic to ohmic material with increase of Ag content. The room temperature electrical conductivities are found to be in the range of 4.74×10−4 to 3.96×10−2S/m with no major difference in activation energy for all nanocomposites
Photo-reduced route of polyaniline nanofiber synthesis with embedded silver nanoparticles
This work presents a method on the preparation and performance of four silver (Ag) concentrations in polyaniline (PANI) and polyvinyl alcohol (PVA) nanocomposite blend (PNPAg). The synthesis of Ag nanoparticles is first performed by photo reduction and then aniline is polymerized in Ag-PVA matrix. Morphological analysis by SEM and TEM reveals formation of nanoparticles with diameter 30–70 nm. Nanocomposites with lower Ag concentrations have highly aligned PNPAg nanofibers of diameter 50–80 nm and agglomeration for the one with higher concentrations. In addition, FTIR spectra show a systematic change in its characteristic peaks with increase in Ag contents. The crystallinity study depicts the tetragonal crystal structure of metallic nanocomposites having same particle sizes as obtained in SEM and TEM. In order to explore the possible applications of these nanocomposites in electronic industry, their electrical properties are investigated. The in-plane I-V characteristics indicate a transition of polymer nanocomposites from non-ohmic to ohmic material with increase of Ag content. The room temperature electrical conductivities are found to be in the range of 4.74 × 10−4 to 3.96 × 10−2 S/m with no major difference in activation energy for all nanocomposites.The authors express their deep sense of gratitude to SAIF, Department of Instrumentation & USIC, Gauhati University, India, for XRD data collection.Scopu
Pengaruh Pemberian Probiotik dari Mikroba Lokal terhadap Tebal Kerabang, Penurunan Berat, dan Nilai Haugh Unit Telur yang Disimpan Sepuluh Hari
This study was conducted to 1) determine the effect local of probiotic supplements on shell thickness, weight loss persentage, and Haugh unit of eggs which stored ten days; 2) determine the optimal level of supplements local of probiotic on shell thickness, weight loss presentage, and Haugh unit of eggs which stored ten days. This research was held on 08--19 December 2014 in the CV. Varia Agung Jaya henhouse laying in the District of Seputih Mataram, Center of Lampung Regency and continued on 20 December 2014--18 January 2015 in the Laboratory of Microbiology, Laboratory of Molecular Biology Faculty, University of Lampung. The study used completely randomized design (CRD) with 4 treatments of local probiotics in the diet (0%, 1%, 2%, and 3%) and 5 replications. Data obtained was analyzed using analysis of variance at 5% level and continued Orthogonal Polynomial test at 5% level. Based on these results we can conclude: effect of local probiotics in the diet (0,1,2, and 3%) no significant (P> 0.05) on the weight loss presentage and Haugh unit of eggs which stored ten days, but significant (P <0.05) on shell thickness. Increasing the percentage of local probiotic on the ration will improve shell thickness indicated by the regression equation ŷ = 0.42 + 0,24x, with r = 0.68 and R2 = 0.47.
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Mass Redistribution Causes the Structural Richness of Ion-Irradiated Surfaces
We show that the “sputter patterning” topographical instability is determined by the effects of ion impact-induced prompt atomic redistribution and that erosion—the consensus predominant cause—is essentially irrelevant. We use grazing incidence small angle x-ray scattering to measure in situ the damping of noise or its amplification into patterns via the linear dispersion relation. A model based on the effects of impact-induced redistribution of those atoms that are not sputtered away explains both the observed ultrasmoothening at low angles from normal incidence and the instability at higher angles.Engineering and Applied Science
SPORT: A new sub-nanosecond time-resolved instrument to study swift heavy ion-beam induced luminescence - Application to luminescence degradation of a fast plastic scintillator
We developed a new sub-nanosecond time-resolved instrument to study the
dynamics of UV-visible luminescence under high stopping power heavy ion
irradiation. We applied our instrument, called SPORT, on a fast plastic
scintillator (BC-400) irradiated with 27-MeV Ar ions having high mean
electronic stopping power of 2.6 MeV/\mu m. As a consequence of increasing
permanent radiation damages with increasing ion fluence, our investigations
reveal a degradation of scintillation intensity together with, thanks to the
time-resolved measurement, a decrease in the decay constant of the
scintillator. This combination indicates that luminescence degradation
processes by both dynamic and static quenching, the latter mechanism being
predominant. Under such high density excitation, the scintillation
deterioration of BC-400 is significantly enhanced compared to that observed in
previous investigations, mainly performed using light ions. The observed
non-linear behaviour implies that the dose at which luminescence starts
deteriorating is not independent on particles' stopping power, thus
illustrating that the radiation hardness of plastic scintillators can be
strongly weakened under high excitation density in heavy ion environments.Comment: 5 figures, accepted in Nucl. Instrum. Methods
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