Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “PRODUCTIVITY”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
DOE OSTI2011

Measurement of the B{sup 0} Production Cross Section in pp Collisions at {radical}(s)=7 TeV

Measurements of the differential production cross sections d{sigma}/dp{sub T}{sup B} and d{sigma}/dy{sup B} for B{sup 0} mesons produced in pp collisions at {radical}(s)=7 TeV are presented. The data set used was collected by the CMS experiment at the LHC and corresponds to an integrated luminosity of 40 pb{sup -1}. The production cross section is measured from B{sup 0} meson decays reconstructed in the exclusive final state J/{psi}K{sub S}{sup 0}, with the subsequent decays J/{psi}{yields}{mu}{sup +}{mu}{sup -} and K{sub S}{sup 0}{yields}{pi}{sup +}{pi}{sup -}. The total cross section for p{sub T}{sup B}>5 GeV and |y{sup B}|<2.2 is measured to be 33.2{+-}2.5{+-}3.5 {mu}b, where the first uncertainty is statistical and the second is systematic.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Strategies for the production of cell wall‐deconstructing enzymes in lignocellulosic biomass and their utilization for biofuel production

Summary Microbial cell wall‐deconstructing enzymes are widely used in the food, wine, pulp and paper, textile, and detergent industries and will be heavily utilized by cellulosic biorefineries in the production of fuels and chemicals. Due to their ability to use freely available solar energy, genetically engineered bioenergy crops provide an attractive alternative to microbial bioreactors for the production of cell wall‐deconstructing enzymes. This review article summarizes the efforts made within the last decade on the production of cell wall‐deconstructing enzymes in planta for use in the deconstruction of lignocellulosic biomass. A number of strategies have been employed to increase enzyme yields and limit negative impacts on plant growth and development including targeting heterologous enzymes into specific subcellular compartments using signal peptides, using tissue‐specific or inducible promoters to limit the expression of enzymes to certain portions of the plant or certain times, and fusion of amplification sequences upstream of the coding region to enhance expression. We also summarize methods that have been used to access and maintain activity of plant‐generated enzymes when used in conjunction with thermochemical pretreatments for the production of lignocellulosic biofuels.

09 BIOMASS FUELS↗
DOE OSTI2015

Chlamydomonas as a model for biofuels and bio‐products production

Summary Developing renewable energy sources is critical to maintaining the economic growth of the planet while protecting the environment. First generation biofuels focused on food crops like corn and sugarcane for ethanol production, and soybean and palm for biodiesel production. Second generation biofuels based on cellulosic ethanol produced from terrestrial plants, has received extensive funding and recently pilot facilities have been commissioned, but to date output of fuels from these sources has fallen well short of what is needed. Recent research and pilot demonstrations have highlighted the potential of algae as one of the most promising sources of sustainable liquid transportation fuels. Algae have also been established as unique biofactories for industrial, therapeutic, and nutraceutical co‐products. Chlamydomonas reinhardtii 's long established role in the field of basic research in green algae has paved the way for understanding algal metabolism and developing genetic engineering protocols. These tools are now being utilized in C. reinhardtii and in other algal species for the development of strains to maximize biofuels and bio‐products yields from the lab to the field.

Scranton, Melissa A.↗
DOE OSTI2018

Global carbon intensity of crude oil production

Producing, transporting, and refining crude oil into fuels such as gasoline and diesel accounts for ~15 to 40% of the “well-to-wheels” life-cycle greenhouse gas (GHG) emissions of transport fuels. Reducing emissions from petroleum production is of particular importance, as current transport fleets are almost entirely dependent on liquid petroleum products, and many uses of petroleum have limited prospects for near-term substitution (e.g., air travel). Better understanding of crude oil GHG emissions can help to quantify the benefits of alternative fuels and identify the most cost-effective opportunities for oil-sector emissions reductions. Yet, while regulations are beginning to address petroleum sector GHG emissions, and private investors are beginning to consider climate-related risk in oil investments, such efforts have generally struggled with methodological and data challenges. First, no single method exists for measuring the carbon intensity (CI) of oils. Second, there is a lack of comprehensive geographically rich datasets that would allow evaluation and monitoring of life-cycle emissions from oils. We have previously worked to address the first challenge by developing open-source oil-sector CI modeling tools [OPGEE, supplementary materials (SM) 1.1]. Furthermore, we address the second challenge by using these tools to model well-to-refinery CI of all major active oil fields globally—and to identify major drivers of these emissions.

02 PETROLEUM↗
DOE OSTI2012

Reduction of Photoautotrophic Productivity in the Cyanobacterium Synechocystis sp. Strain PCC 6803 by Phycobilisome Antenna Truncation

Truncation of the algal light-harvesting antenna is expected to enhance photosynthetic productivity. The wild type and three mutant strains of Synechocystis sp. strain 6803 with a progressively smaller phycobilisome antenna were examined under different light and CO 2 conditions. Surprisingly, such antenna truncation resulted in decreased whole-culture productivity for this cyanobacterium.

14 SOLAR ENERGY↗
DOE OSTI2016

Measurement of the differential cross-sections of prompt and non-prompt production of J / ψ and ψ (2S) in pp collisions at √s = 7 and 8 TeV with the ATLAS detector

The production rates of prompt and non-prompt J/ψ and ψ(2S) mesons in their dimuon decay modes are measured using 2.1 and 11.4 fb -1 of data collected with the ATLAS experiment at the Large Hadron Collider, in proton–proton collisions at √s=7 and 8 respectively. Production cross-sections for prompt as well as non-prompt sources, ratios of ψ(2S) to J/ψ production, and the fractions of non-prompt production for J/ψ and ψ(2S) are measured as a function of meson transverse momentum and rapidity. Lastly, the measurements are compared to theoretical predictions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Measurement of the prompt J /$\psi$ pair production cross-section in pp collisions at $\sqrt{s} = 8$ TeV with the ATLAS detector

The production of two prompt J/ψ mesons, each with transverse momenta p T > 8.5 GeV and rapidity |y| < 2.1, is studied using a sample of proton-proton collisions at $\sqrt{s} = 8$ TeV, corresponding to an integrated luminosity of 11.4 fb –1 collected in 2012 with the ATLAS detector at the LHC. The differential cross-section, assuming unpolarised J/ψ production, is measured as a function of the transverse momentum of the lower-p T J/ψ meson, di-J/ψp T and mass, the difference in rapidity between the two J/ψ mesons, and the azimuthal angle between the two J/ψ mesons. The fraction of prompt pair events due to double parton scattering is determined by studying kinematic correlations between the two J/ψ mesons. The total and double parton scattering cross-sections are compared with predictions. The effective cross-section of double parton scattering is measured to be σ eff = 6.3 ± 1.6(stat)±1.0(syst) mb.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Measurement of $WW/WZ \rightarrow \ell \nu q q^{\prime }$ production with the hadronically decaying boson reconstructed as one or two jets in $pp$ collisions at $\sqrt{s} =8~\text {TeV}$ with ATLAS, and constraints on anomalous gauge couplings

This paper presents a study of the production of WW or WZ boson pairs, with one W boson decaying to e? or µv and one W or Z boson decaying hadronically. The analysis uses 20.2fb -1 of s=8TeVpp collision data, collected by the ATLAS detector at the Large Hadron Collider. Cross-sections for WW / WZ production are measured in high-p T fiducial regions defined close to the experimental event selection. The cross-section is measured for the case where the hadronically decaying boson is reconstructed as two resolved jets, and the case where it is reconstructed as a single jet. The transverse momentum distribution of the hadronically decaying boson is used to search for new physics. Observations are consistent with the Standard Model predictions, and 95% confidence intervals are calculated for parameters describing anomalous triple gauge-boson couplings.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2019

Measurement of $W^\pm$ boson production in Pb+Pb collisions at $\sqrt{s_{\mathrm{NN}}} = 5.02~\text {Te}\text {V}$ with the ATLAS detector

A measurement of W ± boson production in Pb+Pb collisions at √s NN =5.02 TeV is reported using data recorded by the ATLAS experiment at the LHC in 2015, corresponding to a total integrated luminosity of 0.49nb -1 . The W ± bosons are reconstructed in the electron or muon leptonic decay channels. Production yields of leptonically decaying W ± bosons, normalised by the total number of minimum-bias events and the nuclear thickness function, are measured within a fiducial region defined by the detector acceptance and the main kinematic requirements. These normalised yields are measured separately for W + and W - bosons, and are presented as a function of the absolute value of pseudorapidity of the charged lepton and of the collision centrality. The lepton charge asymmetry is also measured as a function of the absolute value of lepton pseudorapidity. In addition, nuclear modification factors are calculated using the W ± boson production cross-sections measured in pp collisions. The results are compared with predictions based on next-to-leading-order calculations with CT14 parton distribution functions as well as with predictions obtained with the EPPS16 and nCTEQ15 nuclear parton distribution functions. No dependence of normalised production yields on centrality and a good agreement with predictions are observed for mid-central and central collisions. For peripheral collisions, the data agree with predictions within 1.7 (0.9) standard deviations for W - (W + ) bosons.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2014

Diboson production at LHC and Tevatron

This is a report at the conference Physics In Collision 2013. The experimental results on physics of diboson production are reviewed. The measurements use pp collision at the LHC with center-of-mass energy [Formula: see text] and 8 TeV, and [Formula: see text] collision at the Tevatron with [Formula: see text]. These include measurements of Wγ, Zγ, WW, WZ and ZZ production. The results are compared with Standard Model predictions, and are interpreted in terms of constraints on charged and neutral anomalous triple gauge couplings.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

Measurement of $WZ$ production and searches for anomalous top quark decays and Higgs boson production using tri-lepton final states in $p\bar{p}$ collisions at $\sqrt{s} = 1.96~\rm{TeV}$

We present the results of three analyses; a $WZ$ production cross section measurement, a search for new physics in anomalous top quark decays, and the search for the standard model Higgs boson, all with final states of three or more leptons -- either electrons or muons -- plus an imbalance of transverse momentum using Tevatron proton and anti-proton collisions at a center--of--mass energy of $\sqrt{s}$ = 1.96 TeV with the D0 detector at the Fermi National Accelerator Laboratory in Chicago, IL. The first analysis reports a measurement of the $WZ \rightarrow \ell^{\prime}\nu\ell\bar{\ell}$ cross section. Using 4.1 $fb^{-1}$ of integrated luminosity, we measure a cross section of 3.90$_{-0.85}^{+1.01}$($stat+syst$) $\pm$ 0.31($lumi$) pb, which is found to be in good agreement with the standard model prediction. The second analysis is an extension of the first, in which we use the same dataset and look for the flavor changing neutral current decay of $t \rightarrow Zq$ in $p\bar {p} \rightarrow t\bar{t} \rightarrow WbZq \rightarrow \ell^{\prime}\nu\ell\bar{\ell} + \rm{jets}$ decays. Here $q$ is considered to be either a $u$ or $c$ quark, and both the $q$ and $b$ quarks decay hadronically. We find no evidence of flavor changing neutral current production and set upper limits on the branching ratio of $BR(t \rightarrow Zq) < 3.2\%$ observed, with an expected limit of $< 3.8\%$, at the 95\% confidence level. Finally, we present a search for the standard model Higgs boson, using associated $WH$ and $ZH$ production, in the $ee\mu$ final state. Now using 9.7 $fb^{-1}$, the full dataset available at D0, we observe no excess above the standard model background prediction and extract limits on the Higgs boson production cross section times branching ratio for a Higgs boson mass range of $m_{H}$ = 100 -- 200 GeV/c$^2$, in intervals of 5 GeV/c$^2$.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2020

Integration of High-Z Converter into Full-scale Production Target for Accelerator-based Production of 99 Mo

NorthStar Medical Technologies is planning to produce the 99Mo isotope via the photonuclear route. The Rhodotron accelerator designed by IBA will be used as an electron-beam source. The Rhodotron is an efficient recirculating accelerator, providing low energy dispersion and a low-emittance electron beam. The nominal beam power is assumed to be 120 kW at 40 MeV. In photonuclear production of 99 Mo, a high-power electron beam impinges on a helium-cooled Mo disk target. Electrons are converted into photons through the Bremsstrahlung process. Consequently, high-energy photons interact with the target nuclei, producing 99 Mo through the 100 Mo(γ, n) 99 Mo reaction. Traditionally, photonuclear production is realized using high-Z material as the electron-to-photon converter. NorthStar plans not to use a high-Z converter in the initial production target design, but it may be interested in the increased production capabilities a high-Z converter can provide. The purpose of this report is to evaluate the advantages and disadvantages of incorporating a high-Z converter into the target design.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2025

Expansion of Carbon Calculator for Land Use and Land Management Change from Biofuels Production (CCLUB) to Address Induced Land Use Changes and Other Indirect Effects of Clean Fuel Production for R&D GREET ® 2024

Since the late 2000s, biofuel life-cycle analysis (LCA) has included induced land use change (ILUC) and other indirect effects (I-effects) of large-scale feedstock production for biofuels. In ILUC and I-effect emissions modeling, economic models are used to simulate the area of land conversion among different land types and other I-effects such as non-feedstock crop production and livestock production that are driven by the scenarios of biofuel production volume shocks. On the other hand, emission factors (EF) models estimate carbon stock changes and GHG emissions associated with these changes. Finally, the area and type of ILUC and I-effects are combined with the EFs to estimate the biofuel ILUC/I-effect GHG emissions in the unit of grams of CO 2 equivalent per MJ biofuel produced (g CO 2 e/MJ).

09 BIOMASS FUELS↗
DOE OSTI2019

A Customizable Approach for the Enzymatic Production and Purification of Diterpenoid Natural Products

Diterpenoids form a diverse class of small molecule natural products that are widely distributed across the kingdoms of life and have critical biological functions in developmental processes, interorganismal interactions, and environmental adaptation. Due to these various bioactivities, many diterpenoids are also of economic importance as pharmaceuticals, food additives, biofuels, and other bioproducts. Advanced genomics and biochemical approaches have enabled a rapid increase in the knowledge of diterpenoid-metabolic genes, enzymes, and pathways. However, the structural complexity of diterpenoids and the narrow taxonomic distribution of individual compounds in often only a single species remain constraining factors for their efficient production. Availability of a broader range of metabolic enzymes now provide resources for producing diterpenoids in sufficient titers and purity to facilitate a deeper investigation of this important metabolite group. Drawing on established tools for microbial and plant-based enzyme co-expression, we present an easily operated and customizable protocol for the enzymatic production of diterpenoids in either Escherichia coli or Nicotiana benthamiana, and the purification of desired products via silica chromatography and semi-preparative HPLC. Using the group of maize (Zea mays) dolabralexin diterpenoids as an example, we highlight how modular combinations of diterpene synthase (diTPS) and cytochrome P450 monooxygenase (P450) enzymes can be used to generate different diterpenoid scaffolds. Purified compounds can be used in various downstream applications, such as metabolite structural analyses, enzyme structure-function studies, and in vitro and in planta bioactivity experiments.

09 BIOMASS FUELS↗
DOE OSTI2026

Synthesis of ARM User Facility Surface Rainfall Datasets to Construct a Best Estimate Value Added Product (PrecipBE)

Surface precipitation measurements are essential for Earth system model (ESM) evaluation and understanding cloud processes. An ever-growing need for robust, temporally evolving, and easy-to-use statistical datasets provides motivation for a baseline ground-based precipitation properties data product. The U.S. Department of Energy Atmospheric Radiation Measurement (ARM) user facility operates an extensive suite of precipitation instruments with various sensitivities and operating mechanisms, which render the decision of which instrument to use based on one or more fixed thresholds challenging and prone to errors and bias. Using a long-term instrument inter-comparison from a unique per-precipitation event perspective, rather than instantaneous sample comparison, we demonstrate that ARM rainfall-measuring instruments are generally consistent with each other at the statistical level. Inter-instrument deviations at the single event level can be large, especially for specific rainfall event properties such as maximum precipitation rates. A machine-learning (ML) analysis using a random forest regressor indicates that in some cases, depending on instrument, local site climatology, and/or specific deployment configuration, certain atmospheric state variables influence the measured quantities in an unpredictable manner. Thus, a-priori weighting of different instruments does not necessarily lead to more accurate and less biased synthesis of instrument data. These results motivate the design of the ARM precipitation best-estimate (PrecipBE) value-added product, which incorporates all valid precipitation data while considering data quality and other instrument limitations. PrecipBE consists of time series and tabular statistics datasets in an easy-to-use and insightful per-precipitation event format. It provides a large set of precipitation event properties supplemented with ancillary data from ARM datasets that correspond to the detected precipitation events. We describe the PrecipBE algorithm and demonstrate its use via the examination of a single-day output as well as a long-term trend analysis of precipitation events at the ARM Southern Great Plains (SGP) site, covering more than 30 years of data. The trend analysis tentatively suggests a long-term temporal tendency for mainly shorter and less intense precipitation events at the SGP site, but a long-term increase in annual rainfall by more than 36 mm (5 %) per decade. This rainfall trend is catalyzed primarily by more extreme event properties of relatively rare, intense precipitation events, with event total and 1 min maximum precipitation rate at a 1 year timeframe increasing up to 5 mm and 9 mm h −1 (several percent) per decade, respectively. While the currently available PrecipBE datasets (at https://adc.arm.gov/discovery/, last access: 8 December 2025) cover rainfall from multiple ARM deployments up to March 2025, PrecipBE is planned to be expanded to include solid-phase precipitation and will soon become an operational product with a several-day lag from real-time. We invite the ARM user community to leverage this new product and welcome user feedback to further enhance the dataset.

Silber, Israel [Pacific Northwest National Laborat↗
DOE OSTI2016

Climate change impacts on net primary production (NPP) and export production (EP) regulated by increasing stratification and phytoplankton community structure in the CMIP5 models

Abstract. We examine climate change impacts on net primary production (NPP) and export production (sinking particulate flux; EP) with simulations from nine Earth system models (ESMs) performed in the framework of the fifth phase of the Coupled Model Intercomparison Project (CMIP5). Global NPP and EP are reduced by the end of the century for the intense warming scenario of Representative Concentration Pathway (RCP) 8.5. Relative to the 1990s, NPP in the 2090s is reduced by 2–16 % and EP by 7–18 %. The models with the largest increases in stratification (and largest relative declines in NPP and EP) also show the largest positive biases in stratification for the contemporary period, suggesting overestimation of climate change impacts on NPP and EP. All of the CMIP5 models show an increase in stratification in response to surface–ocean warming and freshening, which is accompanied by decreases in surface nutrients, NPP and EP. There is considerable variability across the models in the magnitudes of NPP, EP, surface nutrient concentrations and their perturbations by climate change. The negative response of NPP and EP to increasing stratification reflects primarily a bottom-up control, as upward nutrient flux declines at the global scale. Models with dynamic phytoplankton community structure show larger declines in EP than in NPP. This pattern is driven by phytoplankton community composition shifts, with reductions in productivity by large phytoplankton as smaller phytoplankton (which export less efficiently) are favored under the increasing nutrient stress. Thus, the projections of the NPP response to climate change are critically dependent on the simulated phytoplankton community structure, the efficiency of the biological pump and the resulting levels of regenerated production, which vary widely across the models. Community structure is represented simply in the CMIP5 models, and should be expanded to better capture the spatial patterns and climate-driven changes in export efficiency.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1986

Characterization and optimization of hydrogen production by a salt water blue-green alga Oscillatoria sp. Miami BG 7. II - Use of immobilization for enhancement of hydrogen production

The technique of cellular immobilization was applied to the process of hydrogen photoproduction of nonheterocystous, filamentous marine blue-green alga, Oscillatoria sp. Miami BG 7. Immobilization with agar significantly improved the rate and longevity of hydrogen production, compared to free cell suspensions. Rates of H2 production in excess of 13 microliters H2 mg dry/wt h were observed and hydrogen production was sustained for three weeks. Immobilization also provided some stabilization to environmental variability and was adaptable to outdoor light conditions. In general, immobilization provides significant advantages for the production and maintenance of hydrogen photoproduction for this strain.

Phlips, E. J.↗