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There is limited evidence for the acceptability of various drug formulations holding the potential to improve medicines administration to children. Suitable formulations need to meet the requirements of pediatric patients. Previous studies have demonstrated the acceptance of mini-tablets. Oblong tablets may carry more active ingredient content per unit than mini-tablets and could be an important alternative when the drug substance requires administration of higher doses. The primary objective was to demonstrate non-inferiority of acceptability of oblong tablets in comparison to 3 ml glucose syrup in children aged 1 to 5 years. Secondary objectives were investigation of acceptability, swallowability and palatability of mini-tablets, oblong tablets and glucose syrup in children between 1 and 5 years.An open, randomized, single dose two-way cross-over design in two parallel study arms was applied. 280 children were stratified to one of five age groups and randomized to receiving one oblong tablet (2.5 × 6 mm) in comparison either to 3 ml glucose syrup or to three mini-tablets (2 × 2 mm). Acceptability and swallowability were assessed according to pre-defined evaluation criteria. The application of the formulations was video documented to evaluate the palatability.As primary objective, non-inferiority was observed regarding acceptability of the oblong tablet compared to syrup in all age groups (84.4% vs 80.1%, difference 4,29% points with 95% CI of -3.00%,11.57%). For swallowability, superiority of the oblong tablet compared to syrup could be shown (74.5% vs. 53.2%, difference 21.26% points, 95% CI of 11.29%, 31.23%). Regarding palatability,10% of children demonstrated unpleasant reaction after intake of the oblong tablet or mini-tablets as graded by both raters, however, in contrast up to 40% of children after intake of syrup.Oblong tablets are a promising, safe alternative to liquid drug formulations and administration of multiple mini-tablets in children.

Aim To describe the methods and feasibility of the nutritional intervention carried out within the SPRINTT Randomized cotrolled trial. We also illustrate how nutrition interventionists identified participants at risk of malnutrition and the lessons learnt from the nutrition intervention. Findings SPRINTT nutrition intervention was well-received by the majority of the participants. It was mainly carried out using tailored nutrition counselling, but also other means of delivering the intervention were successfully used. Compared with a standard nutrition prescription, an individualized protocol to diagnose malnutrition and follow-up by tailored nutrition counselling helped achieve nutritional targets more effectively in spite of diversity of population in nutritional habits and in some cases reluctance to accept changes. Message The SPRINTT nutrition intervention was feasible and allowed flexibility to the varying needs and cultural differences of this heterogeneous population of frail, older Europeans. It may serve as a model to educate and improve nutrition among community-dwelling older people at risk of mobility limitations. Supplementary Information The online version contains supplementary material available at 10.1007/s41999-020-00438-4., Background The “Sarcopenia and Physical Frailty in Older People: Multicomponent Treatment Strategies” (SPRINTT) project sponsored a multi-center randomized controlled trial (RCT) with the objective to determine the effect of physical activity and nutrition intervention for prevention of mobility disability in community-dwelling frail older Europeans. We describe here the design and feasibility of the SPRINTT nutrition intervention, including techniques used by nutrition interventionists to identify those at risk of malnutrition and to carry out the nutrition intervention. Methods SPRINTT RCT recruited older adults (≥ 70 years) from 11 European countries. Eligible participants (n = 1517) had functional limitations measured with Short Physical Performance Battery (SPPB score 3–9) and low muscle mass as determined by DXA scans, but were able to walk 400 m without assistance within 15 min. Participants were followed up for up to 3 years. The nutrition intervention was carried out mainly by individual nutrition counseling. Nutrition goals included achieving a daily protein intake of 1.0–1.2 g/kg body weight, energy intake of 25–30 kcal/kg of body weight/day, and serum vitamin D concentration ≥ 75 mmol/L. Survey on the method strategies and feasibility of the nutrition intervention was sent to all nutrition interventionists of the 16 SPRINTT study sites. Results Nutrition interventionists from all study sites responded to the survey. All responders found that the SPRINTT nutrition intervention was feasible for the target population, and it was well received by the majority. The identification of participants at nutritional risk was accomplished by combining information from interviews, questionnaires, clinical and laboratory data. Although the nutrition intervention was mainly carried out using individual nutritional counselling, other assisting methods were used as appropriate. Conclusion The SPRINTT nutrition intervention was feasible and able to adapt flexibly to varying needs of this heterogeneous population. The procedures adopted to identify older adults at risk of malnutrition and to design the appropriate intervention may serve as a model to deliver nutrition intervention for community-dwelling older people with mobility limitations. Supplementary Information The online version contains supplementary material available at 10.1007/s41999-020-00438-4.

In order to propose a more precise definition and explore how to reduce ethical losses in randomized controlled clinical trials (RCTs), we set out to identify trial participants who do not contribute to demonstrating that the treatment in the experimental arm is superior to that in the control arm. RCTs emerged mid-last century as the gold standard for assessing efficacy, becoming the cornerstone of the value of new therapies, yet their ethical grounds are a matter of debate. We introduce the concept of unnecessary participants in RCTs, the sum of non-informative participants and non-responders. The non-informative participants are considered not informative with respect to the efficacy measured in the trial in contrast to responders who carry all the information required to conclude on the treatment’s efficacy. The non-responders present the event whether or not they are treated with the experimental treatment. The unnecessary participants carry the burden of having to participate in a clinical trial without benefiting from it, which might include experiencing side effects. Thus, these unnecessary participants carry the ethical loss that is inherent to the RCT methodology. On the contrary, responders to the experimental treatment bear its entire efficacy in the RCT. Starting from the proportions observed in a real placebo-controlled trial from the literature, we carried out simulations of RCTs progressively increasing the proportion of responders up to 100%. We show that the number of unnecessary participants decreases steadily until the RCT’s ethical loss reaches a minimum. In parallel, the trial sample size decreases (presumably its cost as well), although the trial’s statistical power increases as shown by the increase of the chi-square comparing the event rates between the two arms. Thus, we expect that increasing the proportion of responders in RCTs would contribute to making them more ethically acceptable, with less false negative outcomes.

Reliable pediatric pharmacotherapy in all age groups requires the availability of age-appropriate drug administration. Orodispersible films (ODF) are a promising pediatric oral dosage form. ODFs would meet relevant targets: one dosage form matching the full range of pediatric patients, a minimum of non-toxic excipients, a stable drug formulation easily to be produced. However, there is a lack of reliable data on ODFs' acceptability, swallowability and palatability, especially in young children. The primary objective was to demonstrate non-inferiority in acceptability of a drug-free ODF in comparison to glucose syrup in children aged below one year. Secondary objectives were swallowability and palatability of the two formulations.The study was performed in an open, randomized, two-way cross-over design with three age groups: 2-28 days, 29 days-5 months, 6-12 months. 150 children (N = 50 per age group) were randomized to the order of receiving the ODF (2 × 3 cm) and age-adapted amounts of glucose syrup (0.5-3 mL). Deglutition and swallowing were assessed according to predefined evaluation criteria. The application of the formulations was documented by video to evaluate the palatability.The primary objective was confirmed: Non-inferiority of the acceptability of an ODF compared to syrup was demonstrated, even superiority of the ODF was shown (p 0.0001). The secondary endpoints demonstrated positive results including the superior swallowability of the ODF in comparison to syrup (p 0.0001). The palatability assessments were in favor of the ODF.ODFs are a promising and safe alternative to liquid formulations, even for children of very young ages.

The autoignition timing of 1-hexene was controlled in a Homogeneous Charge Compression Ignition (HCCI) engine by reacting the fuel with ozone-containing air prior to its combustion. The experiments were conducted in a single cylinder research engine instrumented with a cylinder pressure sensor. The fuel was chemically characterised using Nuclear Magnetic Resonance (NMR) spectroscopy before and after its reaction with ozone. The NMR analyses showed that this preliminary reaction produced several oxygenated products within the fuel, and was likely to have resulted in the formation of ozonide molecules having a peroxidic structure with several oxygen molecules in series. To understand how this would affect the ignition reactions, the ignition process was modelled numerically using a single-zone chemical kinetic reactor model. The modelling suggested that peroxide molecules decomposed during the compression of the reactants in the engine and advanced ignition timing by promoting early decomposition of the fuel through the formation of radicals.

The challenges faced by the biopharmaceutical industry in its key role to overcome the bottlenecks in innovative medicines development are related to addressing the technical knowledge gaps, the limitations to clinical trial testing, and the lack of clarity in the global pathways and processes to efficient outcomes. It is postulated that the lack of an adequately sized and appropriately trained multi-professional workforce, both in the industry and in the clinical research field, to enable fulfillment of the demanding aims for medicines development is a significant part of the problem. The current global status of pharmaceutical medicine’s efforts to conduct education and training is seen as patchy, inadequate, and without recognition, direction or leadership. It is therefore proposed that the movement towards competency-based education (CBE) should be harnessed, and core competency job and role profiles and competency curricula should be developed. CBE presents a means of addressing the educational and training needs within medicines development, harmonizing the workforce and the requirement for increased inter-professional teamwork. An educational environment in which aspiring and established biomedical professionals could readily learn about the competencies they need to pursue a particular career path is envisioned. Utilizing competencies provides the building blocks to align and harmonize the desired learning outcomes for effective performance amongst a multi-professional workforce. The effective implementation of training programs as described here has the potential to transform drug development procedures into an efficient and integrated process; medical product life-cycle management would result in the availability of better and safer medicines more rapidly, for the benefit of patients and society.

To assess the acceptability and swallowability of several minitablets when administered as a unit dose compared with an equivalent dose of syrup in children aged 6 months to 5 years.The acceptability and swallowability of multiple drug-free minitablets in comparison with glucose syrup was assessed in 372 children of 2 age groups (186 in age group 1 [6-23 months of age] and 186 in age group 2 [2-5 years of age]) in a randomized, 3-way, single administration cross-over study. Age group 1 received 25 minitablets, 100 minitablets, and 5 mL syrup. Age group 2 received 100 minitablets, 400 minitablets, and 10 mL syrup.Superiority was demonstrated in age group 1 for acceptability (25 minitablets, P .017; 100 minitablets, P .0001) and swallowability (25 minitablets and 100 minitablets, both P .0001) compared with syrup. In age group 2, noninferiority of acceptability was found only for 400 minitablets (P .0003), not for 100 minitablets. Subgroup analysis revealed a strong sequential effect. For swallowability, noninferiority could be demonstrated for 100 minitablets (P .01) but not for 400 minitablets.Administration of ≥25 minitablets is well-tolerated, feasible, and safe in children aged from 6 months, and was superior to the equivalent dose of syrup. Children aged1 year accept ≤400 minitablets even better than the equivalent dose of syrup. Minitablets open the perspective for introducing small-sized solid drug formulations for all children, thus, further shifting the paradigm from liquid toward small-sized solid drug formulations.German Clinical Trials Register (DRKS): DRKS00008843.

Autoignition of hydrogen in air was studied in a turbulent flow reactor using OH*-chemiluminescence. High-speed imaging was used to visualise the formation of auto-ignition kernels in the flow, and to analyse the conditions under which temporary stabilisation of the flame kernels occurred. The experiments were carried out at temperatures of 800-850 K, pressures of 0.8-1.2 MPa and an equivalence ratio of phi = 0.25. Measurements of the autoignition delays yielded values in the range of tau = 210-447 ms. The autoignition delay results indicated that, over the range of conditions studied, ignition delays reduced with decreasing pressure. This observation contradicted homogeneous gas-phase kinetic calculations, which predicted an increase in autoignition delay with decreasing pressure. If the kinetic model was altered to include surface reactions at the reactor walls, the calculations could be qualitatively reconciled with the experimental data, suggesting that wall reactions had a significant influence on autoignition delays. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. (Less)

Autoignition of dimethyl ether in air was studied in a turbulent flow-reactor with optical access, at conditions relevant to micro gas turbine combustors. The ignition process was visualized using OH*-chemiluminescence imaging, showing the formation of multiple autoignition kernels along the central axis of the reactor. Ignition delays in the range of τ = 112–310 ms were measured at temperatures of T = 739–902 K, pressures of P = 0.2–0.4 MPa, equivalence ratios of ϕ = 0.225–0.675, and initial flow velocities of Ui = 8–46 m/s. The effect of adding nitrogen to the reactants as a diluent was investigated for mole fractions of additional nitrogen ranging from 0 < XN2 < 0.1. The experimental ignition delays were compared with homogeneous gas-phase chemical kinetic modeling. Comparison between the modeling and experiments showed significant discrepancies, but agreement was improved when heat transfer in the reactor was taken into account in the modeling.

Autoignition of propane in air was visualised in a turbulent flow reactor using natural OH*-chemiluminescence imaging. The spatial and temporal development of autoignition kernels was studied in an optically accessible tubular section of the reactor. Kernel nucleation, movement and growth affected the location and movement of subsequent autoignition sites, and resulted in stagnation of the incoming flow and flashback. The autoignition delays of the reactants were measured under various conditions of temperature, pressure and equivalence ratio, relevant to micro gas turbines: Temperature T= 803-903 K, pressure p = 0.4-0.6 MPa, equivalence ratio phi = 0.2-0.6, mass flow rate of reactants m(r) = 8-21 g/s, with ignition delays tau between 191 and 498 ms. The effect of diluting the propane + air mixtures with CO2 was investigated for mole fractions of 0

The removal of particulate emissions from gasoline injection engines is a new challenge within the exhaust aftertreatment system that will arise with the introduction of limits for particle number emitted by gasoline engines. Besides a possible adjustment of the engine management to lower the particulate emissions, catalyzed gasoline particulate filters (GPF) are conceivable as efficient pollution control devices. As an advantage, these catalyzed filters in addition could be able to support the conversion of all other regulated pollutants. Therefore, an emission study was carried out with systems consisting of a three-way catalyst and a catalyzed GPF and the impact of a dedicated washcoat on the filtration efficiency of the filter was analyzed. The conversion performance of the gasoline particulate filters was examined with regard to carbon monoxide, hydrocarbons and nitrous oxides emissions. Furthermore, the influence of the additional converter on fuel consumption and CO2 emissions over different driving cycles will be discussed. In a detailed exhaust system study a correlation between the distance of engine-outlet to GPF-inlet and the filtration efficiency of the system was observed.

The Precision Robotic Assembly Machine was developed to manufacture the small and intricate laser-driven fusion ignition targets that are being used in the National Ignition Facility. The machine e...

Inertial confinementfusion ignition experiments in the National Ignition Facility require a capsule containing deuterium-tritium fuel at cryogenic temperatures. To better understand how to produce and control the required uniform fuel ice layer, experimental layering targets are fabricated and assembled to be dimensionally similar to the ignition targets and vacuum leaktightat 18 K. Low production yield of these targets demanded a more quantitative understanding of the interfacial behavior of bonded joints and required the development of more deterministic assembly methods. Each sealing joint was individually analyzed, and target components, assembly processes, and tooling were modified as needed to make robust leaktight targets. The function, design, and assembly methods of experimental layering targets are described.

A small-scale combustor was set up to analyze the combustion of natural gas and two mixtures of partially reformed natural gas. The partially reformed mixtures can be formed using biomass to feed the endothermic reforming reactions. Before combusting these mixtures in a gas turbine, experimental work was done on a primary zone combustion chamber to examine the combustor behavior when switching from natural gas to the wet and dry hydrogen-rich mixtures. Temperature profiles, flame location and ignition limits have been investigated for a variety of stoichiometries and several air temperatures. Possible problems concerning blow-off, flashback, increased pollutant products and excessive liner wall temperatures were analyzed. It was concluded that the switch in operation from natural gas to these wet and/or dry partially reformed natural gas mixtures lowers the blow-off limits while maintaining similar liner wall temperature profiles. Furthermore, no significant changes in pollutant production were observed. Flame area, shape and position display considerable differences in combustion regime for the three tested fuel types.

Description and results of a novel apparatus for determining the flow conductance through a laser drilled hole in a spherical shell for inertial confinement fusion experiments are described. The instrument monitors the pressure of an enclosed volume containing the laser pressure drilled capsule as air bleeds through the hole into the shell. From these measurements one obtains the conductance of the fill hole. This system has proven to be a valuable tool for verifying the conduct conductance into the capsule in a timely and nondestructive manner.

An investigation on the central-pilot stage of a Siemens Industrial Turbomachinery 4th Generation DLE prototype test burner has been performed to understand the emission performance and operability. The core section, which is defined as RPL (Rich premixed lean) plays an important role for full burner combustion operation by stabilizing the main and pilot flames at different operating condition. Optimal fuel-air flow through the RPL is critical for multiple stages mixing and main flame anchoring. Heat and radical production from the central stage provides the ignition source and required heat for burning the main flame downstream of the RPL section. Surrounding the RPL outside wall cooling air has been blown through an annular passage. The cooling air protects the RPL wall from overheating and provides the oxygen source for the secondary combustion downstream of the RPL. At rich operation unburned hydrocarbon/radicals can pass the RPL and burns by the co-flow air entrainment. To determine the flame stabilization and operability, an atmospheric pressure test has been accomplished using methane as a fuel. Primary flame zone can be identified by a thermocouple placed outside the RPL wall and secondary combustion zone at the exit has been examined by chemiluminescence imaging. Emission measurement and LBO (Lean blow out) limits have been determined for different equivalence ratios from 1.8 to LBO limit. Co-flow air temperature was changed from 303 K to 573 K to evaluate the secondary combustion and RPL wall heat transfer effect on flame stability/emission. It is found that equivalence ratio has strong effect on the RPL flame stabilization (primary/secondary flame). Emissions/radical generation were also influenced by the chemical reaction inside the RPL. It can be noticed that co-flow air temperature has a significant role on emission, LBO and flame stabilization for the central-pilot stage burner due to the heat loss from the flame zone and RPL wall. A chemical kinetic network (Chemkin™) and CFD modelling approaches (Fluent) are employed to understand in detail the chemical kinetics, heat transfer effect and flow field inside the RPL (combustion and heat loss inside and emission capability). Experiment shows that the low CO and NOx levels can be achieved at lean and rich condition due to lower flame temperature. Present experimental results by changing equivalence ratio, residence time and co-flow temperature, creates a complete map for the RPL combustion, which is key input for full 4th Generation DLE burner design.

This paper describes a Cassegrain optics-based chemiluminescence sensor (CS) for measurements in gas turbine combustors. The chemiluminescence sensor measures the equivalence ratio of reacting fuel and air mixtures, and can identify the flame location, in partially premixed flames. It has the potential for monitoring the degree of premixedness of reacting fuel and air in industrial gas turbine combustors, where operation with lean premixed mixtures is important for reduction of NO, emissions. The spatial resolution of the sensor is evaluated by comparing OH* chemiluminescence measurement from the CS with laser induced OH fluorescence, in the cone-shaped premixed flame of a Bunsen burner. The ability of the sensor to measure in a modified micro-gas turbine environment burning a methane/air, as well as, a methane/ water/air flame (humidified flame) is also demonstrated. (Less)

Flame flashback from the combustion chamber to the premixing section is a major operability issue when using high H2 content fuels in lean premixed combustors. Depending on the flow-field in the combustor, flashback can be triggered by different mechanisms. In this work, three flashback mechanisms of H2/CH4 mixtures were visualized in an atmospheric variable-swirl burner using high speed OH* chemiluminescence imaging. The H2 mole fraction of the tested fuel mixtures varied between 0.1 and 0.9. The flow-field in the combustor was varied by changing the swirl number from 0.0 to 0.66 and the total air mass-flow rate from 75 to 200 SLPM (standard liters per minute). The following three types of flashback mechanism were observed: Flashback caused by combustion induced vortex breakdown (CIVB) occurred at swirl numbers ≥0.53 for all of the tested fuel mixtures. Flashback in the boundary layer (BL) and flame propagation in the premixing tube caused by auto-ignition were observed at low swirl numbers and low total air mass-flow rates. The temporal and spatial propagation of the flame in the optical section of the premixing tube during flashback was studied and flashback speed for different mechanisms was estimated. The flame propagation speed during flashback was significantly different for the different mechanisms.

A patient in his late 50s who suffered from necrotising fasciitis is described in this case report. The patient first presented at the chest pain unit, where he reported of respiratory distress and showed systemic signs of an infection. Because of progressive skin lesions indicative of necrotising fasciitis on both the lower extremities, the patient was immediately rushed into surgery and was treated at the intensive care unit. Despite receiving immediate treatment, the patient died of this rapidly spreading infectious disease. Because of the fast advance of this disease, we would like to emphasise the importance of early recognition of symptoms.

The requirements for beam and target alignment for successful ignition experiments on the National Ignition Facility (NIF) are stringent: the average of beams to the target must be within 25 μm. Beam and target alignment are achieved with the Target Alignment Sensor (TAS). The TAS is a precision optical device that is inserted into target chamber center to facilitate both beam and target alignment. It incorporates two camera views (upper/lower and side) mounted on each of two stage assemblies (jaws) to view and align the target. It also incorporates a large mirror on each of the two assemblies to reflect the alignment beams onto the upper/lower cameras for beam alignment. The TAS is located in the chamber using reference features by viewing it with two external telescope views. The two jaws are adjusted in elevation to match the desired beam and target alignment locations. For some shot setups, a sequence of TAS positions is required to achieve the full setup and alignment. In this paper we describe the TAS, the characterization of the TAS coordinates for beam and target alignment, and summarize pointing shots that demonstrate the accuracy of beam-target alignment.

The National Ignition Facility (NIF) is a 192-beam high energy laser designed for Inertial Confinement Fusion (ICF), and High Energy Density (HED) and basic science experiments. In order to achieve ignition with an ICF target, the beam and target alignment must be performed within very tight specifications. At the same time, in order to be able to conduct the wide range of HED and basic science experiments, the facility must be able to meet the tight tolerances for both main and offset backlighter beams and targets. To diagnose the ignition event, many different target diagnostics are employed, including optical, x-ray, and nuclear diagnostics. These target diagnostics must also be positioned accurately and reliably within very tight specifications in order to ensure good data is acquired. In this paper, we describe the strategy for beam, target, and diagnostic alignment at NIF.

The National Ignition Facility (NIF) requires high resolution live images of regions inside the target chamber in order to align diagnostic instruments to fusion targets and to monitor target stability. To view the interior of the target chamber, we modified a commercial 11-inch Schmidt-Cassegrain telescope to develop the Opposed Port Alignment System (OPAS). There are two OPAS systems installed on the target chamber ports directly opposite the diagnostics. This paper describes the optical design, highlighting the two key modifications of the telescope. The first key modification was to reposition the Schmidt corrector plate and to uniquely mount the secondary mirror to a precision translation stage to adjust focus from 5.5 m to infinity. The stage is carefully aligned to ensure that the telescope’s optical axis lies on a straight line during focus adjustments. The second key modification was a custom three element lens that flattens the field, corrects residual aberrations of the Schmidt-Cassegrain and, with a commercial 1:1 relay lens, projects the final image plane onto a large format 50 mega-pixel camera. The OPAS modifications greatly extend the Schmidt-Cassegrain telescope’s field of view, producing nearly diffraction-limited images over a flat field covering ±0.4 degrees. Also discussed in the paper are the alignment procedure and the hardware layout of the telescope.

Objective To explore the acceptance of uncoated drug-free mini-tablets 2 mm in diameter in children aged 0.5–6 years and their ability to swallow the mini-tablets. Methods 60 children aged 0.5–6 years (10 subjects per year of life) were enrolled in our prospective, open random, two-way cross-over exploratory pilot study. The children were administered either an uncoated drug-free mini-tablet 2 mm in diameter with a beverage of their choice or 3 ml of glucose syrup 15% followed by the other formulation. Deglutition was visually assessed for the two different dosage forms using a predefined criteria list. Results The study hypothesis was that children would accept the liquid formulation better than the solid mini-tablets. Surprisingly, the authors found that the acceptance of the mini-tablets, defined as immediate swallowing or chewing first with subsequent swallowing, was higher or at least equal to that of the syrup. Very young children (6–12 months) were fully capable of swallowing the mini-tablets and may even accept them better than the sweet liquid formulation. Some children aged between 2 and 4 years chewed the tablets before swallowing, but still accepted them quite well. The acceptance rate of the mini-tablets in the different age groups was much higher than expected. Conclusions Uncoated mini-tablets seem to be a very promising alternative to liquid formulations and could be used at an earlier age in paediatric drug therapy than previously anticipated.

Summary form only given. We have installed the National Ignition Facility Neutron Imaging System. The imaging system provides information about the areal density of fuel in the various regions of the capsule implosion. A long line of sight enables imaging both the primary 14 MeV neutrons as well as the down-scattered neutrons with energies in the range of 9-12 MeV. The imager is a pinhole camera where the pinhole is located 325 mm from the target and the imaging plane is located 28 m from the target. The long absorption length of neutrons requires precise alignment of these extended imager components in order to have high detection efficiency and strong background rejection. The imaging plane is a 150 mm square scintillating fiber bundle 50 mm thick. The bundle consists of 250 μm square fibers. The fiber bundle is aligned such that the fibers point at the target. The pointing is accomplished using a retro reflection of a laser alignment device aligned to the imager line of sight. The 200 mm long pinhole is aligned to the imager line of sight using the Opposed Port Alignment System. The imager line of sight was registered to the alignment system to calculate the precise position of the pinhole. The ability of the positioning manipulator to both place and maintain the precise location of the pinhole, were monitored using the positioning imaging system as well as laser alignment device. Here we describe the various aspects of the imaging system alignment to enable the acquisition of neutron images as well as the estimated pointing errors of the first shot imaged.

We demonstrate the hohlraum radiation temperature and symmetry required for ignition-scale inertial confinement fusion capsule implosions. Cryogenic gas-filled hohlraums with 2.2 mm-diameter capsules are heated with unprecedented laser energies of 1.2 MJ delivered by 192 ultraviolet laser beams on the National Ignition Facility. Laser backscatter measurements show that these hohlraums absorb 87% to 91% of the incident laser power resulting in peak radiation temperatures of T(RAD)=300 eV and a symmetric implosion to a 100 μm diameter hot core.

The lean stability limit of a prototype syngas burner is investigated. The burner is a three sector system, consisting of a separate igniter, stabilizer and Main burner. The ignition sector, Rich-Pilot-Lean (RPL), can be operated with both rich or lean equivalence values, and serves to ignite the Pilot sector which stabilizes the Main combustion sector. The RPL and Main sectors are fully premixed, while the Pilot sector is partially premixed. The complexity of this burner design, especially the ability to vary equivalence ratios in all three sectors, allows for the burner to be adapted to various gases and achieve optimal combustion. The gases examined are methane and a high H2 model syngas (10% CH4, 22.5% CO, 67.5% H2). Both gases are combusted at their original compositions and the syngas was also diluted with N2 to a low calorific value fuel with a Wobbe index of 15 MJ/m3. The syngas is a typical product of gasification of biomass or coal. Gasification of biomass can be considered to be CO2 neutral. The lean stability limit is localized by lowering the equivalence ratio from stable combustion until the limit is reached. To get a comparable blowout definition the CO emissions is measured using a non-dispersive infrared sensor analyzer. The stability limit is defined when the measured CO emissions exceed 200 ppm. The stability limit is measured for the 3 gas mixtures at atmospheric pressure. The RPL equivalence ratio is varied to investigate how this affected the lean blowout limit. A small decrease in stability limit can be observed when increasing the RPL equivalence ratio. The experimental values are compared with values from a perfectly stirred reactor modeled (PSR), under burner conditions, using the GRI 3.0 kinetic mechanism for methane and the San Diego mechanism for the syngas fuels.

The emission composition is measured for a prototype burner while varying the equivalence ratio in discrete portions of the burner. The burner is a three sector system, consisting of a separate igniter, pilot/stabilizer and main burner. The design allows for discrete control of equivalence ratio in each of the three sectors. The ignition sector, designated RPL (Rich-Pilot-Lean), operates from rich to lean equivalence values, and serves to ignite the pilot sector, which, in turn, stabilizes the main combustion sector. All three burner sections are premixed. The burner is operated at atmospheric pressure with inlet flows heated to 650 K (±8 K). Tests were performed for three gases: methane, a model syngas (10% CH4, 22.5% CO, 67.5% H2), and dilute syngas. The dilute gas includes sufficient nitrogen to lower the heating value to 15 MJ/m3. The model syngas and diluted syngas are representative of fuels produced by gasification process. The burner emissions, specifically, CO, CO2, O2 and NOx, are measured while holding the RPL equivalence value constant and varying the equivalence ratio of the pilot and main sectors. The equivalence ratios for pilot and main sectors are chosen such that the total burner equivalence ratios remain constant during a test sequence. The target total equivalence ratio for each gas is chosen such that all experiments should have the same flame temperature.

Gas turbine systems are predominantly designed to be fuelled with gaseous fuels within a limited Wobbe index range (typically HHV = 45–55 MJ/Nm3 or 1200–1480 Btu/scf). When low calorific fuel gases are fired, the engine will be forced to operate outside its design envelope. The added mass flow will typically raise the cycle pressure ratio and in two-shaft designs also raise the gas generator shaft speed. In this study, the response of a natural gas fired simple cycle two-shaft gas turbine operating at full firing temperature is investigated. A model based on the Volvo Aero Corp. VT4400 gas turbine (originally Dresser Rand DR990) characterized by one compressor and two expander maps is considered. The free turbine is operated at fixed physical speed. Different amounts of N2 or CO2 are added to the fuel path. These two inerts are typically found in large quantities in medium and low calorific fuels. The fuels lower heating value is thus gradually changed from 50 MJ/kg (21.5 kBtu/lb) to 5MJ/kg (2.15 kBtu/lb). Emphasis has been put on predicting the compressor behavior in different resizing scenarios. The full ‘firing temperature’ operating point in the compressor map is tracked as the compressor size is reduced up to 7.5%, high pressure turbine size is increased up to 20%, low pressure turbine size is changed ±7.5% or up to 10% of steam (c.f. design point compressor air mass flow) is injected between the turbines. Different re-matching schemes are discussed where one turbomachinery component size is fixed and the two other component sizes are changed such that the compressor design point is restored. Finally a re-optimized turbine flow path is computed in a fixed compressor size scenario. Results are, as far as possible, given as non-dimensional parameter groups for easy comparison with other machines.Copyright © 2009 by ASME

Gas turbine systems are predominantly designed to be fuelled with gaseous fuels within a limited Wobbe index range (typically HHV = 45–55 MJ/Nm3 or 1200–1480 Btu/scf). When low calorific fuel gases are fired, the engine will be forced to operate outside its design envelope. The added mass flow will typically raise the cycle pressure ratio and in two-shaft designs also raise the gas generator shaft speed. Typical constraints to be considered due to the altered fuel composition are pressure loads, shaft torques, shaft overspeeds, centrifugal overloading of disks and blades, combustor flameout, surge and flutter limits for the turbomachinery. This poses limitations to usable fuel choices. In this study, the response of a natural gas fired simple cycle two-shaft gas turbine is investigated. A lean premixed combustor is also included in the model. Emphasis has been put on predicting the turbomachinery and combustor behavior as different amounts of N2 or CO2 are added to the fuel path. These two inerts are typically found in large quantities in medium and low calorific fuels. The fuels lower heating value is thus gradually changed from 50 MJ/kg (21.5 kBtu/lb) to 5MJ/kg (2.15 kBtu/lb). A model, based on the Volvo Aero Corp. VT4400 gas turbine (originally Dresser Rand DR990) characterized by one compressor and two expander maps is considered. The free turbine is operated at fixed physical speed. The operating point is plotted in the compressor map and the turbine maps at three distinct firing temperatures representing turndown from full load to bleed opening point. Gas generator speed and shaft power are shown. Surge margin and power turbine power is plotted. Overall efficiency is computed. The behavior of the Volvo lean premixed combustor is also discussed. Air split, primary zone equivalence ratio and temperature is plotted. Combustor loading, combustion intensity and pressure drop is graphed. Results are, as far as possible, given as non-dimensional parameter groups for easy comparison with other machines.Copyright © 2009 by ASME

When low calorific value gases are fired, the performance and stability of gas turbines may deteriorate due to a large amount of inertballast and changes in working fluid properties. Since it is rather rare to have custom-built gas turbines for low lower heating value (LHV) operation, the engine will be forced to operate outside its design envelope. This, in turn, poses limitations to usable fuel choices. Typical restraints are decrease in Wobbe index and surge and flutter margins for turbomachinery. In this study, an advanced performance deck has been used to quantify the impact of firing low-LHV gases in a generic-type recuperated as well as unrecuperated gas turbine. A single-shaft gas turbine characterized by a compressor and an expander map is considered. Emphasis has been put on predicting the off-design behavior. The combustor is discussed and related to previous experiments that include investigation of flammability limits, Wobbe index, flame position, etc. The computations show that at constant turbine inlet temperature, the shaft power and the pressure ratio will increase; however, the surge margin will decrease. Possible design changes in the component level are also discussed. Aerodynamic issues (and necessary modifications) that can pose severe limitations on the gas turbine compressor and turbine sections are discussed. Typical methods for axial turbine capacity adjustment are presented and discussed.

Summary form only given. Planned cryogenic ignition experiments at the National Ignition Facility (NIF) are expected to use a fill tube to introduce liquid DT into the capsule prior to solid layer formation. During the implosion, this fill tube is expected to form a hydrodynamic jet at deceleration that could quench ignition if this jet is sufficiently large and penetrates the core early enough. We have begun the first indirect-drive experiments to explore the hydrodynamic effects of fill tubes on implosion performance. In these experiments, we have concentrated on developing diagnostic techniques by replacing the fill tube with a bump on the outer shell surface. This bump is hydrodynamically similar to a fill tube but much easier to fabricate and simulate. We present experimental data and calculations for various bump diameters and heights obtained from two techniques: emission imaging of Ti-doped shell material that has been swept into the core at times near peak compression, and backlit imaging of the bump at early times

Aviation fuel is a petroleum product that fulfills the Standard Specification for Aviation Turbine Fuels. Crude oil has been the raw material for production of aviation fuels for many years. Since the availability of crude oil is predicted to be limited in the future, alternative raw materials for aviation fuels are highly desirable. A Swedish company, Oroboros AB, has developed a novel clean synthetic jet fuel, LeanJet®. The fuel is produced synthetically from synthesis gas (Syngas) by the Fischer-Tropsch process. A comparative experimental investigation of combustion properties has been performed, comparing the synthetic jet fuel with Jet A1. The following parameters were investigated in an atmospheric combustor, which was originally designed for a Volvo Aero turbine (VT40): • Emissions of NOx, CO and HC; • Ignition and extinction points; • Liner temperatures; • Soot levels in the combustor. The emission measurements showed good combustion efficiency with low HC and CO for both fuels. With very lean mixtures, however, both the CO and the HC levels increased for the synthetic fuel. The nitrous oxides for the synthetic jet fuel were reduced over the operation conditions investigated. Qualitative reduction of soot levels was also seen for the synthetic jet fuel. The fuels showed no difference in material temperature along the combustor wall. Small differences in ignition characteristics were found, but no differences in extinction were observed.

Recently we were asked to produce target capsules with bumps on the surface. The bumps were to test the effects of fill tubes in future targets. The bumps desired were to be Gaussian in shape and from 60 to 40 {micro}m in diameter and from 1 to 6 {micro}m high. The capsules had a nominal diameter of 500 {micro}m. The approach we used was to align a precision aperture to the capsule and coat through the aperture onto the capsule surface using plasma polymer coating. The bumps were characterized using optical microscopy, Wyko interferometry, and AFM sphere mapping.

A modern gas turbine compressor, with its highly aerodynamically loaded blades, is sensitive to changes in profile shape and to surface roughness. Fouling is inevitable, despite highly efficient filtration systems. The remedy to this problem is washing. There are two different approaches, on-line or off-line washing. The off-line wash is the most effective one, whilst on-line washing only prolongs the interval between off-line washes. Most findings in this field are highly empirical, being based on some 50 years of industrial gas turbine operation. This paper is an investigation of the two-phase flow in the bellmouth of the compressor during off-line washing conditions. The unit under study was the GTX100 turbo-set. Computational fluid dynamics (CFD) is used in this paper to perform a detailed study of the flow field. The main emphasis has been on studying the characteristics of the injected spray used for cleaning of the compressor. The benefit of heating this fluid is of special interest, since if this heating can be avoided, the outage time for the off-line compressor wash can be shortened. To provide the CFD computations with accurate boundary conditions for the spray, laser-based measurements of a spray, originating from an authentic wash nozzle, have been conducted. The commercial CFD program Star-Cd has been used for all computations. The computations show that the water injected, regardless of its inlet temperature, is cooled down to ambient air temperature well before the spray reaches the inlet guide vanes. This indicates that heating of the wash fluid can be abolished. The airflow seems not to be to influenced by the injected fluid to any great extend.

For more than ten years, we have been working on R&D for X-band accelerator structures for the JLC/NLC linear collider. Several types of Detuned (DS) and Damped Detuned Structures (DDS) have been successfully designed and fabricated. They have been experimentally tested at both low power and high power to characterize their mechanical and electrical properties. Recently we started developing a new type of damped detuned structure with optimized round-shaped cavities (RDDS). This paper discusses the special specifications, design methods, fabrication procedures, measurement technologies, and anticipated future improvements for all these structures.

Steady flow in axial one-stage turbines is assessed numerically and experimentally. The simulations are performed on coarse meshes using a standard numerical approach (3D, steady state, kε-turbulence model, wall function at solid boundaries). In order to allow for conclusions drawn from these rapid numerical studies, the approach was compared with an explicit LDA (Laser Doppler anemometry) mapping of the velocity field downstream the rotor on a representative turbine stage. A two-component LDA system allowed for measurements of axial and tangential velocity components at varying depth (radius) in the flow channel, Measurements thus correspond to a full plane at constant axial position in the rotating frame of reference of the rotor. Comparison between LDA velocity mapping and CFD results shows good agreement. A series of subsequent simulations is thus used to judge the impact of varied blade/stage design parameters. Two turbine layouts are defined for identical operating conditions and shaft power. The flow in the unshrouded rotor blade row is analyzed for the influence of varying tip clearance size and the dependency on stage velocity triangles. – Known correlations for tip clearance losses (typically used in mean line predictions) are used, though the blade row geometry considered is beyond the limits the correlations are intended for. The absolute loss level found in CFD simulations differs significantly from what is expected when using loss correlations. Still the variation with tip gap size is predicted well by some of the investigated models. As dependency of tip clearance losses on stage velocity triangles is considered, none of the tested correlations gives results consistent with the numerical simulations. The use of standard correlations ‘beyond the limits’ is thus considered to introduce high uncertainty. Due to the good consistency between LDA and numerical results, the conclusions are considered to be valid for stage designs similar to the ones analyzed.

Experiments that characterize and develop a high energy-density half-hohlraum platform for use in benchmarking radiation hydrodynamics models have been conducted at the National Ignition Facility (NIF). Results from the experiments are used to quantitatively compare with simulations of the radiation transported through an evolving plasma density structure, colloquially known as an N-wave. A half-hohlraum is heated by 80 NIF beams to a temperature of 240 eV. This creates a subsonic diffusive Marshak wave, which propagates into a high atomic number Ta2O5 aerogel. The subsequent radiation transport through the aerogel and through slots cut into the aerogel layer is investigated. We describe a set of experiments that test the hohlraum performance and report on a range of x-ray measurements that absolutely quantify the energetics and radiation partition inside the target.

An experimental and computational study of the near-wall combustion in a Homogeneous Charge Compression Ignition (HCCI) engine has been conducted by applying laser based diagnostic techniques in combination with numerical modeling. Our major intent was to characterize the combustion in the velocity- and thermal boundary layers. The progress of the combustion was studied by using fuel tracer LIF, the result of which was compared with LDA measurements of the velocity boundary layer along with numerical simulations of the reacting boundary layer. Time resolved images of the PLIF signal were taken and ensemble averaged images were calculated. In the fuel tracer LIF experiments, acetone was seeded into the fuel as a tracer. It is clear from the experiments that a proper set of backgrounds and laser profiles are necessary to resolve the near-wall concentration profiles, even at a qualitative level. Partial resolution of the velocity boundary layer was enabled by using a slightly inclined LDA probe operated in back-scatter mode. During these conditions, it was possible to acquire velocity data within 0.2 mm from the wall. A one-dimensional model of the flow field was devised to make the connection between the thermal and the velocity boundary layer. The investigations suggest that wall interaction is not the responsible mechanism for the rather high emissions of unburned hydrocarbons from HCCI engines. It is believed that the delayed oxidation, indicated by the fuel tracer LIF experiments and numerical simulations, is due to the thermal boundary layer. From the data at hand, it is concluded that the thermal boundary layer is on the order of 1 mm thick. In this boundary layer the reactions are delayed but not quenched. (Less)

Turbulent flame speeds have been measured in a single cylinder S.I. engine and in a stationary atmospheric burner. One- and two-point LDA has been used to measure turbulence intensities and integral length scales. Stretching, in terms of Karlovitz numbers could be estimated from these measurements. The influence of moving average filtered turbulence on the flame speed in the S.I. engine is in agreement with the burner experiments. Previously reported signs of quenching of small flames in the S.I. engine, due to excessive turbulence could not be found for larger flames.

A 1.8 m X-band damped-detuned structure (DDS-3) has been fabricated and characterized as part of the structure development program towards a TeV-scale e/sup +/e/sup -/ linear collider. In this joint venture, the Cu cells were precision-fabricated by LLNL, diffusion-bonded into a monolithic structure by KEK, and the structure completed and tested by SLAC. The overall process constitutes a baseline for future high-volume structure manufacture.

A joint development project to design a new photolithography steeping machine capable of 150 nanometer overlay accuracy was completed by Ultratech Stepper and the Lawrence Livermore National Laboratory. The principal result of the project is a next-generation product that will strengthen the US position in step-and-repeat photolithography. The significant challenges addressed and solved in the project are the subject of this report. Design methods and new devices that have broader application to precision machine design are presented in greater detail while project specific information serves primarily as background and motivation.

The first inertial confinement fusion implosion experiments with equimolar deuterium-tritium thermonuclear fuel have been performed on the National Ignition Facility. These experiments use 0.17 mg of fuel with the potential for ignition and significant fusion yield conditions. The thermonuclear fuel has been fielded as a cryogenic layer on the inside of a spherical plastic capsule that is mounted in the center of a cylindrical gold hohlraum. Heating the hohlraum with 192 laser beams for a total laser energy of 1.6 MJ produces a soft x-ray field with 300 eV temperature. The ablation pressure produced by the radiation field compresses the initially 2.2-mm diameter capsule by a factor of 30 to a spherical dense fuel shell that surrounds a central hot-spot plasma of 50 μm diameter. While an extensive set of x-ray and neutron diagnostics has been applied to characterize hot spot formation from the x-ray emission and 14.1 MeV deuterium-tritium primary fusion neutrons, thermonuclear fuel assembly is studied by m...

An approach and development plan for the production of replicated variable line spacing X-ray reflection gratings on lightweight substrates is described. The gratings will be arrayed in spectrometers to analyze the soft X-rays gathered by the telescopes flown aboard the European Space Agency (ESA) "X-ray Multi- Mirror Mission" (XMM). The mission requires about 750 gratings to form 3 arrays. Each array provides a grating area of approximately 5 square meters. From relatively few master gratings, the low blaze angle gratings will be replicated onto 55 gram substrates having an equivalent length/thickness aspect ratio s40. We will describe the criteria used for selecting the substrate design and material. A multi-phased study to solve identified technical problems associated with the replication of these gratings is also described. We will report on the present status of the substrates and replication process.

The Reflection Grating Spectrometer Experiment (RGS), which has been selected for flight on the European Space Agency's X-Ray Multi-Mirror Mission (XMM), includes two arrays of reflection gratings that are placed in the X-ray optical path behind two separate grazing incidence X-ray telescopes. Each of the grating arrays picks off roughly half the X-ray light emanating from its telescope and diffracts it to a dedicated strip of charge-coupled device (CCD) detectors offset from the telescope focal plane. The arrays contain 224 100 mm X 200 mm gratings, each mounted at a graze angle of 1.58° to the incident beam. The gratings are produced by epoxy replication of a common master onto very thin substrates. Both the gratings and the detectors are mounted on a Rowland circle which also includes the telescope focus. In this paper, we review the current state of both the engineering and the optical designs for the grating arrays.

Recent advances in cryogenic layering include improved surface roughness characterization of many layers formed using 'slow-cool' and 'rapid-cool' protocols. At 0.25 K below the melt, slow-cooled layers meet the NIF smoothness requirement. However, at 1.5 K below the melt grain-boundary misalignments dominate the layer roughness and cause it to exceed the smoothness specification. Rapid-cool of the layer to 1.5 K below the melt shows promise for meeting the ignition requirements. Much of the current research effort is aimed at characterizing the onset of roughness during rapid cooling and determining the scale of the resulting roughness.

The notion of using a narrow bore fill tube to charge an ignition capsule in situ with deuterium-tritium (DT) fuel is very attractive because it eliminates the need for cryogenic transport of the target from the filling station to the target chamber, and in principle is one way of allowing any material to be considered as an ablator. We are using the radiation hydrocode HYDRA [M. M. Marinak et al., Phys. Plasmas 8, 2275 (2001)] in two dimensions to study the effect of fill tubes on graded copper-doped Be ignition capsule implosions. The capsule is ∼1.1-mm radius and driven at ∼300eV. Fill tubes are made of glass and range in diameter from 10–20μm. These are inserted between 5 and 40μm into the ablator surface, and a glue layer around the capsule ∼2-μm thick is included. The calculations are unusually demanding in that the flow is highly nonlinear from the outset, and very high angular resolution is necessary to capture the initial evolution of the tube, which is complex. Despite this complexity, the net r...