Small gas turbine engine technology

Performance of small gas turbine engines in the 250 to 1,000 horsepower size range is significantly lower than that of large engines. Engines of this size are typically used in rotorcraft, commutercraft, general aviation, and cruise missile applications. Principal reasons for the lower efficiencies of a smaller engine are well known: component efficients are lower by as much as 8 to 10 percentage points because of size effects. Small engines are designed for lower cycle pressures and temperatures because of smaller blading and cooling limitations. The highly developed analytical and manufacturing techniques evolved for large engines are not directly transferrable to small engines. Thus, it was recognized that a focused effort addressing technologies for small engies was needed and could significantly impact their performance. Recently, in-house and contract studies were undertaken at the NASA Lewis Research Center to identify advanced engine cycle and component requirements for substantial performance improvement of small gas turbines for projected year 2000 applications. The results of both in-house research and contract studies are presented. In summary, projected fuel savings of 22 to 42 percent could be obtained. Accompanying direct operating cost reductions of 11 to 17 percent, depending on fuel cost, were also estimated. High payoff technologies are identified for all engine applications, and recent results of experimental research to evolve the high payoff technologies are described

Low NO(x) heavy fuel combustor program

The 'low nitrogen oxides heavy fuel combustor' program is described. Main program objectives are to generate and demonstrate the technology required to develop durable gas turbine combustors for utility and industrial applications, which are capable of sustained, environmentally acceptable operation with minimally processed petroleum residual fuels. The program will focus on 'dry' reductions of oxides of nitrogen, improved combustor durability, and satisfactory combustion of minimally processed petroleum residual fuels. Other technology advancements sought include: fuel flexibility for operation with petroleum distillates, blends of petroleum distillates and residual fuels, and synfuels (fuel oils derived from coal or shale); acceptable exhaust emissions of carbon monoxide, unburned hydrocarbons, sulfur oxides and smoke; and retrofit capability to existing engines

Measuring Racial-Ethnic Diversity in California's Nonprofit Sector

Presents survey findings on the racial/ethnic diversity of the state's nonprofit boards, executive directors, and staff and on the characteristics of racially/ethnically diverse organizations including size, field of activity, location, and budget

The RAI travels to Latin America: Measuring regional authority under regime change

This paper presents a new dataset on regional authority in 27 Latin American and Caribbean countries for 1950–2010 based on the Regional Authority Index (RAI), which makes it possible to compare regional authority over time and across regions. We explain conceptualization, operationalization, and coding decisions with the aim of making judgments explicit, and therefore open to amendment or refutation. We present substantive observations about the variation across countries and over time and discuss the implications and challenges of expanding the RAI to contexts in which democracy and authoritarianism alternate

Salivary Metabolomic Signatures and Body Mass Index in Italian Adolescents: A Pilot Study

Context: Obesity surveillance is scarce in adolescents, and little is known on whether salivary metabolomics data, emerging minimally invasive biomarkers, can characterize metabolic patterns associated with overweight or obesity in adolescents. Objective: This pilot study aims to identify the salivary molecular signatures associated with body mass index (BMI) in Italian adolescents. Methods: Saliva samples and BMI were collected in a subset of n = 74 young adolescents enrolled in the Public Health Impact of Metal Exposure study (2007-2014). A total of 217 untargeted metabolites were identified using liquid chromatography-high resolution mass spectrometry. Robust linear regression was used to cross-sectionally determine associations between metabolomic signatures and sex-specific BMI-for-age z-scores (z-BMI). Results: Nearly 35% of the adolescents (median age: 12 years; 51% females) were either obese or overweight. A higher z-BMI was observed in males compared to females (P = .02). One nucleoside (deoxyadenosine) and 2 lipids (18:0-18:2 phosphatidylcholine and dipalmitoyl-phosphoethanolamine) were negatively related to z-BMI (P < .05), whereas 2 benzenoids (3-hydroxyanthranilic acid and a phthalate metabolite) were positively associated with z-BMI (P < .05). In males, several metabolites including deoxyadenosine, as well as deoxycarnitine, hyodeoxycholic acid, N-methylglutamic acid, bisphenol P, and trigonelline were downregulated, while 3 metabolites (3-hydroxyanthranilic acid, theobromine/theophylline/paraxanthine, and alanine) were upregulated in relation to z-BMI (P < .05). In females, deoxyadenosine and dipalmitoyl-phosphoethanolamine were negatively associated with z-BMI while deoxycarnitine and a phthalate metabolite were positively associated (P < .05). A single energy-related pathway was enriched in the identified associations in females (carnitine synthesis, P = .04). Conclusion: Salivary metabolites involved in nucleotide, lipid, and energy metabolism were primarily altered in relation to BMI in adolescents

Compressive Sensing of Signals Generated in Plastic Scintillators in a Novel J-PET Instrument

The J-PET scanner, which allows for single bed imaging of the whole human body, is currently under development at the Jagiellonian University. The dis- cussed detector offers improvement of the Time of Flight (TOF) resolution due to the use of fast plastic scintillators and dedicated electronics allowing for sam- pling in the voltage domain of signals with durations of few nanoseconds. In this paper we show that recovery of the whole signal, based on only a few samples, is possible. In order to do that, we incorporate the training signals into the Tikhonov regularization framework and we perform the Principal Component Analysis decomposition, which is well known for its compaction properties. The method yields a simple closed form analytical solution that does not require iter- ative processing. Moreover, from the Bayes theory the properties of regularized solution, especially its covariance matrix, may be easily derived. This is the key to introduce and prove the formula for calculations of the signal recovery error. In this paper we show that an average recovery error is approximately inversely proportional to the number of acquired samples

Application of the Compress Sensing Theory for Improvement of the TOF Resolution in a Novel J-PET Instrument

Nowadays, in Positron Emission Tomography (PET) systems, a Time of Flight information is used to improve the image reconstruction process. In Time of Flight PET (TOF-PET), fast detectors are able to measure the difference in the arrival time of the two gamma rays, with the precision enabling to shorten significantly a range along the line-of-response (LOR) where the annihilation occurred. In the new concept, called J-PET scanner, gamma rays are detected in plastic scintillators. In a single strip of J-PET system, time values are obtained by probing signals in the amplitude domain. Owing to Compress Sensing theory, information about the shape and amplitude of the signals is recovered. In this paper we demonstrate that based on the acquired signals parameters, a better signal normalization may be provided in order to improve the TOF resolution. The procedure was tested using large sample of data registered by a dedicated detection setup enabling sampling of signals with 50 ps intervals. Experimental setup provided irradiation of a chosen position in the plastic scintillator strip with annihilation gamma quanta

Novel method for hit-position reconstruction using voltage signals in plastic scintillators and its application to Positron Emission Tomography

Currently inorganic scintillator detectors are used in all commercial Time of Flight Positron Emission Tomograph (TOF-PET) devices. The J-PET collaboration investigates a possibility of construction of a PET scanner from plastic scintillators which would allow for single bed imaging of the whole human body. This paper describes a novel method of hit-position reconstruction based on sampled signals and an example of an application of the method for a single module with a 30 cm long plastic strip, read out on both ends by Hamamatsu R4998 photomultipliers. The sampling scheme to generate a vector with samples of a PET event waveform with respect to four user-defined amplitudes is introduced. The experimental setup provides irradiation of a chosen position in the plastic scintillator strip with an annihilation gamma quanta of energy 511~keV. The statistical test for a multivariate normal (MVN) distribution of measured vectors at a given position is developed, and it is shown that signals sampled at four thresholds in a voltage domain are approximately normally distributed variables. With the presented method of a vector analysis made out of waveform samples acquired with four thresholds, we obtain a spatial resolution of about 1 cm and a timing resolution of about 80 p

Clinical Improvement of Active Tuberculosis Patients with Complex Treatment and Nutritional Supplementation

Abstract: Global incidence of tuberculosis, especially multiple-drug resistant tuberculosis, has been increasing, despite development and use of various antimicrobial drugs for decades, leading to 2 million deaths a year. We evaluated the effect of micronutrient supplementation as an adjunct to standard treatment of patients with active pulmonary tuberculosis, on clinical improvement and frequency of adverse events on 120 patients aged 20 to 65 years diagnosed with active pulmonary tuberculosis at the Kiev Department of Phthisiatry. All participants (Test group) were prescribed standard medication supplemented with vitamin/essential nutrients. A Control group (n=100) of patients recently treated with standard medication alone at this facility were selected by matching to Test patients by stage of disease, confounding conditions, gender, and alcohol consumption. Standard clinical and diagnostic methods were applied to determine baseline values and at the termination of the study. After a two-month period of intensive chemotherapy, cavity healing (primary measure) occurred in 98% of the Test Group, but only in 69% of the Control Group. Furthermore, the Ziehl-Neelson sputum test was negative in 100% of the Test group, but only in 88% of the Control group. Resolution of respiratory compromise was higher in the Test group (87%) than in the Control group (78%). Furthermore, supplementation with vitamin/essential nutrients resulted in a significant decrease in the frequency and severity of adverse events from chemotherapy; only 11% in the Test group experienced adverse events while 46% did so in the Control group. In conclusion, clinical efficacy of chemotherapy was enhanced significantly with adjunctive use of nutrient supplementation. In addition, micronutrient supplementation decreased the frequency and severity of adverse effects from chemotherapy

Does health-related quality of life improve for advanced pancreatic cancer patients who respond to gemcitabine? Analysis of a randomized phase III trial of the cancer and leukemia group B (CALGB 80303)

Context: Gemcitabine for advanced pancreatic cancer (APC) is palliative and the prognosis is poor, making health-related quality of life (HRQOL) particularly important. Objectives: We evaluated HRQOL with the EuroQol (EQ-5D™) in patients with APC participating in Cancer and Leukemia Group B 80303, a multicenter, double-blind, randomized trial comparing overall survival (OS) between two treatment arms: gemcitabine with bevacizumab or gemcitabine with placebo. Methods: A consecutive subsample of patients was invited to complete the EQ-5D surveys. Because neither clinical nor HRQOL outcomes differed based on the study arm, analyses were pooled. Changes in mean scores from baseline to eight weeks and the prognostic value of the EQ-5D were evaluated. Results: Mean index scores remained stable (0.78 at baseline [n = 267], 0.79 at eight weeks [n = 186], P = 0.34, Wilcoxon signed rank test), attributable to a modest deterioration of physical function domain scores coincident with small improvements in pain and anxiety/depression scores. A small decline in visual analogue scale scores was observed (70.7 vs. 68.2, P = 0.026). HRQOL changes within chemotherapy response strata revealed stable index scores but a trend of worsened physical function among patients with disease progression compared with those with stable or improved disease. Visual analogue scale scores trended downward over time irrespective of chemotherapy response status, with a statistically meaningful deterioration in patients who progressed (68.9 vs. 64.4, P = 0.029). Baseline scores from both EQ-5D scales were significant predictors of OS in Cox proportional hazard models. Conclusion: Response to gemcitabine treatment in APC is not associated with appreciable improvement of global HRQOL. Small improvements in pain and mood are observed despite progressive functional decline. Those who respond to gemcitabine may experience a slight slowing of functional deterioration