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NASA NTRS1985

Electromagnetic hot ion beam instabilities - Quasi-linear theory and simulation

This paper considers the quasi-linear theory of the right- and left-hand resonant electromagnetic instabilities driven by a hot ion beam streaming parallel to a magnetic field in a homogeneous Vlasov plasma. Using the single-mode approximation, the time evolutions of important parameters are obtained to show that for the range of parameters considered, reduction of the beam speed and formation of temperature anisotropies are the most significant factors in the quasi-linear stabilization process. Combining both instabilities in a quasi-linear study is found to produce a roughly equal mixture of both polarizations and relatively isotropic conditions for tenuous beam densities and low initial beam drift speeds. Computer simulations are used to compare with the quasi-linear results. The simulations justify the single-mode assumption, verify that quasi-linear changes are the means of saturation for the parameter range of concern, and check the nonlinear evolution of the system when both modes are present.

Rogers, B.↗

NASA NTRS1988

Long decoding runs for Galileo's convolutional codes

Decoding results are described for long decoding runs of Galileo's convolutional codes. A 1 k-bit/sec hardware Viterbi decoder is used for the (15, 1/4) convolutional code, and a software Viterbi decoder is used for the (7, 1/2) convolutional code. The output data of these long runs are stored in data files using a data compression format which can reduce file size by a factor of 100 to 1 typically. These data files can be used to replicate the long, time-consuming runs exactly and are useful to anyone who wants to analyze the burst statistics of the Viterbi decoders. The 1 k-bit/sec hardware Viterbi decoder was developed in order to demonstrate the correctness of certain algorithmic concepts for decoding Galileo's experimental (15, 1/4) code, and for the long-constraint-length codes in general. The hardware decoder can be used both to search for good codes and to measure accurately the performance of known codes.

Lahmeyer, C. R.↗

NASA NTRS1989

Molecular gas, the interstellar medium, and star formation in S0 and Sa galaxies

The results are presented of a survey for CO J = 1 - 0 emission from S0 and S0/a galaxies. The results show that molecular gas is abundant within some early-type disk galaxies, and that the range in the ratio of molecular gas to atomic gas mass is similar to those in other disk galaxies. In the S0 and S0/a galaxies studied, estimated rates of star formation are substantially smaller than, but efficiencies of star formation are roughly the same as, those in Sb or Sc galaxies. Although the rate of cooling of the hot, X-ray emitting gas may be close to the estimated stellar mass return rate in the sample, the star formation rate probably exceeds both by a significant factor.

Thronson, Harley A., Jr.↗

NASA NTRS1990

An atlas of mixed-morphology pairs

Current theories of galaxy formation imply that environment is the most important factor in deciding whether a collapsing region becomes a spiral galaxy or an elliptical galaxy. If this is the case, then isolated pairs comprising a galaxy of each morphology provide an especially interesting test, since, strictly speaking, they should not exist. The first phase of studying E-S pairs is to define a sample which is genuinely isolated and genuinely E-S. The catalog compiled by Karachentsev is the most useful Northern Hemisphere starting point, containing 603 pairs which obeyed certain well-defined angular isolation criteria. All of these pairs now have velocities, enabling further removal of at least some of the non-physical binaries. The conventional cutoff at 500 km s(exp -1) was used for this purpose. However, the morphological types were estimated from Palomar Sky Survey prints, and are consequently not very accurate. It was therefore decided to obtain good charge coupled device (CCD) images in the B-band of all pairs from the Karachentsev sample which were classified as either E-S (73 pairs) or E-SO (91 pairs), for a total of 164 pairs. This includes the 24 pairs with known redshift differences greater than 500 km s(exp -1) (9 E-S and 15 E-SO), which were also imaged in this survey, not only for completeness but also in case the criteria were later changed, or the redshifts were found to be in error. A total of 198 CCD frames were obtained between February 1986 and the present, with most of the observations being completed by the summer of 1987. A number of missing stragglers and replacements for poor quality images were taken more recently. Most observations used the number 1-0.9m telescope at Kitt Peak, with a few frames from the 2.1m. Some pairs required more than one image due to their separation. The morphological study did not require photometric conditions, but calibrations were made for almost all images anyway, and the weather was probably photometric at least half of the time, at least to an accuracy of around 0.1 magnitudes. The results of this first phase will be published in the form of an Atlas, from which any interested readers will be able to select their own sub-sample using their preferred morphological criteria.

Sharp, N. A.↗

NASA NTRS1995

The Role of Chemically Depleted Mantle in the Formation of Coronae on Venus

Without extensive plate subduction to act as a recycling mechanism, a thick layer of buoyant, depleted mantle material may accumulate beneath the thermal lithosphere on Venus due to the pressure-release melting that occurs during crustal formation. Such a layer could be the key factor that allows coronae to form on Venus but not on Earth. Coronae are roughly circular volcano-tectonic features that are interpreted as a manifestation of small-scale upwelling and are unique to Venus. The topographic expression of coronae is highly variable, ranging from domes to plateaus, with or without moats or single or multiple outer rises. In addition to why coronae from on Venus but not on Earth, two outstanding questions in the study of coronae are how the full range of topographic profiles are produced and the relationship between topography and the annulus of fractures that characterize coronae.

Coronae↗

NASA NTRS2008

Crystallinity of Fe-Ni Sulfides in Carbonaceous Chondrites

The main long-term goal of this research is to understand the physical conditions in the early solar nebula through the detailed characterization of a key class of mineral present in all primitive materials: Fe-Ni sulfides [1&2]. Fe-Ni sulfides can take dozens of structures, depending on the temperature of formation, as well as other physico-chemical factors which are imperfectly understood. Add to this the additional varying factor of Ni content, and we have a potentially sensitive cosmothermometer [3]. Unfortunately, this tool requires exact knowledge of the crystal structure of each grain being considered, and there have been few (none?) studies of the detailed structures of sulfides in chondritic materials. We report here on coordinated compositional and crystallographic investigation of Fe-Ni sulfides in diverse carbonaceous chondrites, initially Acfer 094 (the most primitive CM2 [4]) Tagish Lake (a unique type C2 [5]), a C1 lithology in Kaidun [6], Bali (oxidized CV3 [7]), and Efremovka (reduced CV3 [7]).

Zolensky, Michael E.↗

NASA NTRS2019

The Omics of Stem Cell Mediated Regeneration: A Pilot Single Cell RNA-Seq Study of Mechanotransduction

Mechanical forces are potent modulators of stem cell based tissue regenerative mechanisms, inducing cell fate decisions and tissue specific commitment. A unique platform for investigating mechanotransduction is spaceflight, where microgravity and altered fluid mechanics provide a loading-null experimental condition. Seminal investigations of regenerative capacity in a wholly regenerative species, the newt model, and in a variety of totipotent and adult stem cell populations have demonstrated the detrimental effects of unloading on maintenance of stem cell based regeneration. Of particular interest is the observation that unloading interferes with the transition of stem cell pools from proliferative state to differentiation commitment. In this work we sought to test the hypothesis that gravity mechanotransduction regulates stem cell tissue regenerative processes by modulating stem cell proliferation and differentiation fates at specific cell cycle stages. To do this, clonally-derived ESCs were plated on a collagen matrix and expanded for 36 hours before re-plating on a non-adherent culture dish in the absence of leukemia inhibitory factor (LIF) to form spheroid aggregate EBs. After formation, the EBs were transferred to a collagen matrix coated culture dishes and given 4 days to allow implantation and outgrowth. In parallel, totipotent ESCs were plated 24 hours before mechanical stimulation on collagen matrix culture dishes in the presence of LIF to maintain totipotency and serve as un-differentiation committed controls. The EBs and ESCs were then subjected to either a 60 minute pulse of gravity (static loading) or 60 minutes of cyclic stretch (dynamic loading) mechanotransduction. Six hours post-stimulation, we used a 10X Genomics Single Cell controller to generate bar-coded single cell Illumina libraries and sequenced expressomes for 5,000 static loaded cells, representative of a change in gravity mechanotransduction, 5,000 dynamic loaded cells, representative of tissue loading associate with physiologic function, and 5,000 unstimulated 1g control cells. The comparison of these 3 libraries by cluster assignment based on like gene expression patterns show substantial alteration in cluster geometry due to mechanical loading. Specifically the mechanically loaded EB outgrowth cells to retain potency markers (PAX6, SOX2, CD34) and suppress early commitment markers (Dhh, VCAN, Igf1). Whereas the EBs cultured under the non-stimulated conditions display clear departure from the ESC expressome with lineage commitment markers upregulated and several tissue specific markers being expressed (BMP "early musculoskeletal development, Mesp1" early cardiovascular cell lineage). These markers are not seen in the mechano-stimulated cultures or the totipotent ESC cultures. Comparison of like clusters between our experimental conditions revealed an array of regenerative and stem cell genes are significantly mechano-regulated. Of particular importance CDKN1a/p21, a gene shown by previous investigation of our research team to be significantly upregulated in unloading, was suppressed in the static and dynamic loaded EBS. In addition to CDKN1a/p21 many genes related to cell cycle and transitory differentiation markers had elevated expression in the mechano-stimulated EBs, but surprisingly these trends were not observed in the ESC cultures. This study is the first of its kind investigating for mechano-signaling and mechano-regulated pathways, and has alre

Single cell RNA-sequecing↗

NASA NTRS1984

Effects of simulated weightlessness on bone mineral metabolism

It is pointed out that prolonged space flight, bedrest, and immobilization are three factors which can produce a negative calcium balance, osteopenia, and an inhibition of bone formation. It is not known whether the effects of gravity on bone mineral metabolism are mediated by systemic endocrine factors which affect all bones simultaneously, or by local factors which affect each bone individually. The present investigation has the objective to test the relative importance of local vs. systemic factors in regulating the bone mineral response to conditions simulating weightlessness. Experiments were conducted with male Sprague-Dawley rats. The test conditions made it possible to compare the data from weighted and unweighted bones in the same animal. The obtained findings indicate that a decrease in bone mass relative to control value occurs rapidly under conditions which simulate certain aspects of weightlessness. However, this decrease reaches a plateau after 10 days.

Globus, R. K.↗

NASA NTRS1994

The Role of Crack Formation in Chevron-Notched Four-Point Bend Specimens

The failure sequence following crack formation in a chevron-notched four-point bend 1 specimen is examined in a parametric study using the Bluhm slice synthesis model. Premature failure resulting from crack formation forces which exceed those required to propagate a crack beyond alpha (min) is examined together with the critical crack length and critical crack front length. An energy based approach is used to establish factors which forecast the tendency of such premature failure due to crack formation for any selected chevron-notched geometry. A comparative study reveals that, for constant values of alpha (1) and alpha (0), the dimensionless beam compliance and stress intensity factor are essentially independent of specimen width and thickness. The chevron tip position, alpha (0) has its primary effect on the force required to initiate a sharp crack. Small values for alpha (0) maximize the stable region length, however, the premature failure tendency is also high for smaller alpha (0) values. Improvements in premature failure resistance can be realized for larger values of alpha (0) with only a minor reduction in the stable region length. The stable region length is also maximized for larger chevron based positions, alpha (1) but the chance for premature failure is also raised. Smaller base positions improve the premature failure resistance with only minor decreases in the stable region length. Chevron geometries having a good balance of premature failure resistance, stable region length, and crack front length are 0.20 less than or equal to alpha (0) is less than or equal to 0.30 and 0.70 is less than or equal to alpha (1) is less than or equal to 0.80.

Calomino, Anthony M.↗

NASA NTRS2002

Nutrition and renal stone disease in space

There is a growing body of evidence from the National Aeronautics and Space Administration and the Russian space program showing that humans exposed to the microgravity environment of space have a greater risk for developing renal stones. Increased bone resorption and the attendant hypercalciuria and hyperphosphaturia contribute significantly to raising the urinary state of saturation with respect to the calcium salts, namely calcium oxalate and calcium phosphate. In addition, other environmental and dietary factors may adversely affect urine composition and increase stone formation risk during space flight. For example, reductions in urinary volume, pH, and citrate contribute to raising stone formation risk. In addition to raising the risk for calcium stone formation, this metabolic profile is conducive to the formation of uric acid stones. Although observations to date have suggested that there may actually be a reduced food intake during the early phase of flight, crew members on longer-duration flights may increase food intake and be at increased risk for stone formation. Taken together, these findings support the use of nutritional recommendations for crew members that would serve to reduce the stone-forming propensity of the urinary environment. Pharmacologic intervention should be directed at raising urinary volumes, diminishing bone losses, and preventing reductions in urinary pH and citrate. Success in reducing the risk for stone formation in astronauts would also be of potential major benefit to the estimated 20 million Americans with nephrolithiasis.

Review↗

NASA NTRS2024

Comprehensive Observations and Geostatistics of Slope Streaks within the Olympus Mons Aureole

Slope streaks (SS) are enigmatic linear features characterized by relatively low-albedo features that appear and fade on high-albedo slopes on Mars. Despite numerous hypotheses proposed to explain their formation, the primary mechanism behind SS remains elusive. Here, we examine 702 SS features using 32 multitemporal Context Imager (CTX) images and mesoscale modeling data obtained from a site (centered at 31.230°N, 216.281°E) in the Olympus Mons Aureole region. Our investigation revealed several key findings that shed light on the dynamics of SS formation and fading. We discovered a significant preference for SS formation on south-facing (equator-facing) slopes compared to north-facing slopes, with SS being over seven times more likely to occur on the former. Furthermore, SS formation was found to be seasonal with significantly enhanced by a factor of ∼6 near the equinoxes (from solar longitude Ls 337°-42° and 136°-227°) compared to other times of the year. Our analysis also revealed a correlation between the rates of SS formation and fading, with scree slopes exhibited the fastest-fading SS also experiencing the highest rates of newly-formed SS. Additionally, we measured the median starting and stopping slopes of SS to be 23.4° and 14.9°, respectively, significantly below the angle of repose of sand. These low slopes suggest the necessity for an energetic trigger mechanism to initiate SS formation. Infrared spectroscopy revealed that the principal distinction between the material inside and outside of a SS lies in the reduced abundance of dust within the streak. Notably, this site demonstrates the highest rates of SS formation (a 29.6% increase in new SS per Mars year) and fading (a 12% fading of SS per Mars year) ever quantified. These elevated rates may be attributed to the site's topography, which facilitates calm surficial nighttime winds throughout the year, leading to widespread dust deposition. Daytime downhill winds near the ridgelines of S-facing slopes may then trigger movement of newly deposited dust aggregates or alternatively, a Knudsen pump phenomenon could serve as a potential trigger for SS. We propose that SS is inhibited during the northern summer solstice season due to the relatively clear aphelion atmosphere, which limits dust deposition. Similarly, the lack of triggering activity during the winter solstice is likely due to more moderate daytime winds. Overall, our findings are consistent with the wind-triggered dry avalanche hypothesis as a plausible explanation for SS formation.

D E Stillman↗

NASA NTRSDate not supplied

Genomic and Phenotypic Associations to Predict Human Sensitivity to SpaceRadiation

High-linear energy transfer (LET) ionizing radiation is a major health hazard for astronauts who will be exposed to galactic cosmic rays during upcoming lunar and Mars missions. Predicting and mitigating this risk requires understanding the factors underlying individual radiation sensitivity. We started to address this challenge by identifying the genomic and phenotypic associations with sensitivity to low and high-LET ionizing radiation ex vivo in over 750 healthy human donors. We exposed primary human blood mononuclear cells to simulated galactic cosmic ray components: 350MeV/n 28Si, 350MeV/n 40Ar and 600MeV/n 56Fe particles, at 1.1 and 3 particles/100 sq.m fluences, as well as 0.1 Gy and 1 Gy doses of gamma rays, and analyzed the outcomes at 4 and 24 hours post-irradiation. We quantified DNA damage and repair responses based on 53BP1+ radiation-induced foci formation, together with oxidative stress and changes in secreted factors including immune cytokines and exosomes. We also analyzed phenotypic associations with spontaneous DNA repair foci at baseline prior to irradiation. We identified an increase in spontaneous DNA repair associated with age and latent viral infection, and observed that human spontaneous DNA repair foci at baseline can serve as a negative predictor of DNA repair and immunoregulatory cytokine production after irradiation. Furthermore, we observed a wide variability of subject- and LET-dependent radiation responses, with radiation-induced DNA repair foci increasing by dose and LET, and high-LET particle radiation resulting in more residual DNA damage compared to low-LET particles and gamma rays. We have developed multiple metrics to quantify human radio sensitivity across the spectrum of conditions. Here we present their dependence on radiation quality and phenotypic variables, including an age-dependent decrease in DNA repair after irradiation, and genomic associations with radio sensitivity based on low-coverage whole genome sequencing. We anticipate that our work will pave the way for understanding the spectrum of human radio sensitivity and identifying targets for countermeasure development to reduce DNA and cellular damage and radiation carcinogenesis during deep space exploration.

GWAS radiation human↗

DOE OSTI2021

Bi-fated tendon-to-bone attachment cells are regulated by shared enhancers and KLF transcription factors

The mechanical challenge of attaching elastic tendons to stiff bones is solved by the formation of a unique transitional tissue. Here, we show that murine tendon-to-bone attachment cells are bi-fated, activating a mixture of chondrocyte and tenocyte transcriptomes, under regulation of shared regulatory elements and Krüppel-like factors (KLFs) transcription factors. High-throughput bulk and single-cell RNA sequencing of humeral attachment cells revealed expression of hundreds of chondrogenic and tenogenic genes, which was validated by in situ hybridization and single-molecule ISH. ATAC sequencing showed that attachment cells share accessible intergenic chromatin areas with either tenocytes or chondrocytes. Epigenomic analysis revealed enhancer signatures for most of these regions. Transgenic mouse enhancer reporter assays verified the shared activity of some of these enhancers. Finally, integrative chromatin and motif analyses and transcriptomic data implicated KLFs as regulators of attachment cells. Indeed, blocking expression of both Klf2 and Klf4 in developing limb mesenchyme impaired their differentiation.

59 BASIC BIOLOGICAL SCIENCES↗

NASA NTRSDate not supplied

Genomic and Phenotypic Predictors of Human Ex Vivo Sensitivity to Simulated Deep Space Radiation

High-linear energy transfer (LET) ionizing radiation is a major health hazard for astronauts who will be exposed to galactic cosmic rays during upcoming lunar and Mars missions. Predicting and mitigating this risk requires understanding the factors underlying individual radiation sensitivity. We started to address this challenge by identifying the genomic and phenotypic associations with sensitivity to low and high-LET ionizing radiation ex vivo in over 750 healthy human donors. We exposed primary human blood mononuclear cells to simulated galactic cosmic ray components: 350 MeV/n 28Si, 350 MeV/n 40Ar and 600 MeV/n 56Fe particles, at 1.1 and 3 particles/100 sq.m fluences, as well as 0.1 Gy and 1 Gy doses of gamma rays, and analyzed the outcomes at 4 and 24 hours post-irradiation. We quantified DNA damage and repair responses based on 53BP1+ radiation-induced foci formation, together with oxidative stress and changes in secreted factors including immune cytokines and exosomes. We also analyzed phenotypic associations with spontaneous DNA repair foci at baseline prior to irradiation. We identified an increase in spontaneous DNA repair associated with age and latent viral infection, and observed that human spontaneous DNA repair foci at baseline can serve as a negative predictor of DNA repair and immunoregulatory cytokine production after irradiation. Furthermore, we observed a wide variability of subject- and LET-dependent radiation responses, with radiation-induced DNA repair foci increasing by dose and LET, and high-LET particle radiation resulting in more residual DNA damage compared to low-LET particles and gamma rays. We have developed multiple metrics to quantify human radiosensitivity across the spectrum of conditions. Here we present their dependence on radiation quality and phenotypic variables, including an age-dependent decrease in DNA repair after irradiation, and genomic associations with radiosensitivity based on low-coverage whole genome sequencing. We anticipate that our work will pave the way for understanding the spectrum of human radiosensitivity and identifying targets for countermeasure development to reduce DNA and cellular damage and radiation carcinogenesis during deep space exploration.

GWAS↗

NASA NTRS2004

Bone and Calcium Metabolism During Space Flight

Understanding bone loss during space flight is one of the most critical challenges for maintaining astronaut health on space exploration missions. Flight and ground-based studies have been conducted to better understand the nature and mechanisms of weightlessness-induced bone loss, and to identify a means to counteract the loss. Maintenance of bone health requires a balance between bone formation and bone resorption. Early space research identified bone loss as a critical health issue, but could not provide a distinction between the bone formation and breakdown processes. The recent identification of collagen crosslinks as markers of bone resorption has made possible a clear understanding that a decrease in bone resorption is an important effect of space flight, with bone formation being unchanged or only slightly decreased. Calcium regulatory factors have also been studied, in an attempt to understand their role in bone loss. The lack of ultraviolet light exposure and insufficient dietary sources of vitamin D often lead to reduced vitamin D stores on long-duration flights. Serum parathyroid hormone (PTH) concentrations are decreased during flight compared to before flight, although small subject numbers often make this hard to document statistically. As expected, reduced PTH concentrations are accompanied by reduced 1,25-dihydroxyvitamin D concentrations. Calcium kinetic studies during space flight confirm and extend the information gained from biochemical markers of bone metabolism. Calcium kinetic studies demonstrate that bone resorption is increased, bone formation is unchanged or decreased, and dietary calcium absorption is reduced during space flight. Evaluations have also been conducted of countermeasures, including dietary, exercise, and pharmacological treatments. In recent studies, many potential countermeasures show promise at mitigating bone loss in ground-based analogs of weightlessness (e.g., bed rest), but require further ground and flight testing to ensure that the beneficial effects are seen in space flight. As we begin to plan for missions to go back to the Moon, and even off to Mars, many questions are yet to be answered. Maintaining bone is one of the greatest challenges, but with a better understanding of the mechanical processes of bone loss, countermeasures can be designed more efficiently, and the solution (or solutions) may be just over the horizon.

Smith, Scott M.↗

NASA NTRSDate not supplied

Genomic and phenotypic predictors of human ex vivo sensitivity to simulated deep space radiation

High-linear energy transfer (LET) ionizing radiation is a major health hazard for astronauts who will be exposed to galactic cosmic rays during upcoming lunar and Mars missions. Predicting and mitigating this risk requires understanding the factors underlying individual radiation sensitivity. We started to address this challenge by identifying the genomic and phenotypic associations with sensitivity to low and high-LET ionizing radiation ex vivo in over 750 healthy human donors. We exposed primary human blood mononuclear cells to simulated galactic cosmic ray components: 350MeV/n (28)Si, 350MeV/n (40)Ar and 600MeV/n (56)Fe particles, at 1.1 and 3 particles/100µm^(2) fluences, as well as 0.1 Gy and 1 Gy doses of gamma rays, and analyzed the outcomes at 4 and 24 hours post-irradiation. We quantified DNA damage and repair responses based on 53BP1^(+) radiation-induced foci formation, together with oxidative stress and changes in secreted factors including immune cytokines and exosomes. We also analyzed phenotypic associations with spontaneous DNA repair foci at baseline prior to irradiation. We identified an increase in spontaneous DNA repair associated with age and latent viral infection, and observed that human spontaneous DNA repair foci at baseline can serve as a negative predictor of DNA repair and immunoregulatory cytokine production after irradiation. Furthermore, we observed a wide variability of subject- and LET-dependent radiation responses, with radiation-induced DNA repair foci increasing by dose and LET, and high-LET particle radiation resulting in more residual DNA damage compared to low-LET particles and gamma rays. We have developed multiple metrics to quantify human radiosensitivity across the spectrum of conditions. Here we present their dependence on radiation quality and phenotypic variables, including an age-dependent decrease in DNA repair after irradiation, and genomic associations with radiosensitivity based on low-coverage whole genome sequencing. We anticipate that our work will pave the way for understanding the spectrum of human radiosensitivity and identifying targets for countermeasure development to reduce DNA and cellular damage and radiation carcinogenesis during deep space exploration.

GWAS↗

NASA NTRS1998

Joint ASRS and NASA Callback on FANS-1 Datalink Operational Incidents

The recent certification and implementation of the Future Air Navigation System (FANS- 1) was based on the benefits of reduced separation minima, ability to optimize flight plans enroute, and the prompt transmission and reception of messages between oceanic controllers and 747-400 aircraft transiting the Pacific. In addition, FANS was intended to supersede High Frequency (HF) radio which has been the staple, yet problematic, long distance communication link for years. However, in the three initial years of operation, FANS has revealed its own unique operational issues. Although some technical and engineering problems have been studied and addressed, little research has been conducted on human factors issues associated with the use of FANS on the flight deck. This lack of prior data on the operational use of FANS prompted a joint NASA/Aviation Safety Reporting System (ASRS) inquiry into FANS datalink. In addition, two foreign air carriers and their respective safety agencies were recruited to participate. This international FANS research effort consisting of three aviation safety agencies and three international commercial air-carriers has provided a unique opportunity for conducting human factors research in an operational environment. An ASRS 'callback' format was chosen for the study as a practical and viable method for capturing FANS events on the flight deck. Initially, 747-400 pilots were encouraged to submit reports to their respective safety agencies if they had experienced any positive or negative incidents with the use of FANS. Upon receipt of a report, it was evaluated and if deemed pertinent to the study, a telephone interview or 'callback' was conducted on the FANS incident to elicit further details, capture the key events, and gather contextual information. Once the operational data collection phase was completed, the reports and interviews were analyzed with two purposes in mind: primarily to identify and address problematic human factors issues with current FANS technology, and, secondarily, to provide 'lessons learned' for future datalink systems and implementation.

Moses, John↗

DOE OSTI2020

Techno-Economic Impact of Diesel Fuel, Labor, and Interest Rates on Bulk-Format and Round Bale Logistics Expenses for Switchgrass

Highlights System-wide sensitivity of bulk-format and round bale logistics responded to different degrees of expense inputs. Biomass size-reduction expenses for bulk-format were consistently less than round-bale chopping. Stack/reclaim operations with high-density-capacity equipment for bulk-format were the highest expenses. Clean-sheet design of stacker/reclaimer and self-compacting bulk trailer may significantly reduce expenses. Abstract . Deterministic cost analyses were conducted for a harvest, storage, preprocessing, and supply system providing 371,870 dry Mg (dMg) year-1 of milled switchgrass (SG) to a biorefinery from 21,929 ha of production fields within 72 km of the biorefinery. Varied input costs of diesel fuel, labor, and interest rate were input into a highly detailed cost analysis for bulk-format and baseline round bale logistics. These operational input factors, potentially reflecting an evolving economic climate or paradigm shift, were examined to provide insight into the cost to deliver preprocessed biomass feedstock for centralized commercial-scale conversions. Total annual costs per dry unit of SG were determined for all combinations of diesel fuel prices of $0.53 L-1, $0.92 L-1, and $1.32 L-1; total labor costs of $20.00 h-1, $28.85 h-1, and $40.00 h-1 singly and uniformly applied across all labor inputs; and three representative interest rates of 6%, 8%, and 12%. Increases in total cost most depended on increases in diesel fuel cost, followed by labor rate, and finally interest rate. Increases in fuel costs from $0.53 L-1 to $1.32 L-1 yielded a total cost increase of about $11.56 dMg-1 and $13.36 dMg-1 for bulk-format and round bale logistics, respectively, for all combinations of labor and interest rates. The overall increase in labor rate ($20.00 h-1 to $40.85 h-1) resulted in increased total costs of about $10.32 dMg-1 for bulk-format logistics and $9.94 dMg-1 for round bale logistics for all fuel and interest rates. The overall increase in interest rate (6% to 12%) resulted in increased total costs of about $6.72 dMg-1 for bulk-format logistics and $4.21 dMg-1 for round bale logistics for all fuel and labor rates. Increases in total costs for combined increases in fuel cost, labor rate, and interest rate were $28.60 dMg-1 and $27.48 dMg-1, yielding maximum total costs of $87.87 dMg-1 and $86.53 dMg-1 for bulk-format and round bale logistics, respectively. Costs were determined for existing equipment systems, including novel use of waste compaction and ejector semi-trailers. The highest potential for cost reductions may require clean-sheet equipment designs specifically tailored for SG, such as forage harvesters that direct-cut standing SG, mobilized stacker-reclaimer technology to not inhibit stack-area footprint, self-compacting ejector trailer technology, and bale grinding technology incorporating controlled mass feeding and shear failure elements. Keywords: Bales, Bioenergy, Bulk-format, Densification, Field chop, Logistics, Transportation

Agriculture↗