Propellantless propulsion is believed to be the best option for interstellar travel. However, photon rockets or solar sails have thrusts so low that maybe only nano-scaled spacecraft may reach the next star within our lifetime using very high-power laser beams. Following into the footsteps of earlier breakthrough propulsion programs, we are investigating different concepts based on non-classical/revolutionary propulsion ideas that claim to be at least an order of magnitude more efficient in producing thrust compared to photon rockets. Our intention is to develop an excellent research infrastructure to test new ideas and measure thrusts and/or artefacts with high confidence to determine if a concept works and if it does how to scale it up. At present, we are focusing on two possible revolutionary concepts: The EMDrive and the Mach-Effect Thruster. The first concept uses microwaves in a truncated cone-shaped cavity that is claimed to produce thrust. Although it is not clear on which theoretical basis this can work, several experimental tests have been reported in the literature, which warrants a closer examination. The second concept is believed to generate mass fluctuations in a piezo-crystal stack that creates non-zero time-averaged thrusts. Here we are reporting first results of our improved thrust balance as well as EMDrive and Mach-Effect thruster models. Special attention is given to the investigation and identification of error sources that cause false thrust signals. Our results show that the magnetic interaction from not sufficiently shielded cables or thrusters are a major factor that needs to be taken into account for proper μN thrust measurements for these type of devices.
Advances in Satellite Conjunction Analysis with OR.A.SIAntonios Arkas
As the number of the manmade objects increases in space, so does the interest and the research effort on the critical and interesting issues of collision probability assessment and decision making for cases of close approach events.
New interesting theoretical analysis has been recently published by Michael Scott Balch, Ryan Martin and Scott Ferson, on the mathematical subtleties connecting the phenomenon of probability dilution with the fundamental difference between frequentist and Bayesian approaches in statistical inference, and inspirational work has been presented from CNES by F.Laporte through his papers which describe JAC software and his approach to covariance realism.
OR.A.SI, the Flight Dynamics software for GEO and LEO that I’ve been developing for the last 17 years in C++, has been endowed since 2012 with early close approach detection based on the TLE files released from JSpOC, calculation of collision probability (S.Alfano method) based on the secondary object details found in CDM (Conjunction Data Message), Middle Man features (processing and analysis of CDM batches released for the same event) and evasive manoeuvre computation.
This new presentation exposes the latest enhancements, of the already powerful OR.A.SI routines, with all these new exiting advances. In brief the contents of the attached presentation are the following:
1. CASI (Close Approach Simulator) – Development of an analytic simulator which produces close approach events for whatever regime (LEO, MEO and GEO), and renders the probabilistic study and analysis of such events independent from the need of a CDM.
2. Computation and visualization of the probability dilution area in the two dimensional space of Kp and Ks scale factors used for the computation of the scaled probability of collision.
3. Computation of the scale factor interval in order to increase covariance realism, based on hypothesis testing with the Kolmogorov-Smirnov test (F.Laporte - CNES).
4. Computation of the effect of evasive manoeuvres, parametrized in time and velocity increment, on the scaled probability of collision.
I welcome you to the subtle but beautiful world of probabilities and inferential statistics or else how we managed to harness our ignorance to precise science!
Advances in Satellite Conjunction Analysis with OR.A.SIAntonios Arkas
As the number of the manmade objects increases in space, so does the interest and the research effort on the critical and interesting issues of collision probability assessment and decision making for cases of close approach events.
New interesting theoretical analysis has been recently published by Michael Scott Balch, Ryan Martin and Scott Ferson, on the mathematical subtleties connecting the phenomenon of probability dilution with the fundamental difference between frequentist and Bayesian approaches in statistical inference, and inspirational work has been presented from CNES by F.Laporte through his papers which describe JAC software and his approach to covariance realism.
OR.A.SI, the Flight Dynamics software for GEO and LEO that I’ve been developing for the last 17 years in C++, has been endowed since 2012 with early close approach detection based on the TLE files released from JSpOC, calculation of collision probability (S.Alfano method) based on the secondary object details found in CDM (Conjunction Data Message), Middle Man features (processing and analysis of CDM batches released for the same event) and evasive manoeuvre computation.
This new presentation exposes the latest enhancements, of the already powerful OR.A.SI routines, with all these new exiting advances. In brief the contents of the attached presentation are the following:
1. CASI (Close Approach Simulator) – Development of an analytic simulator which produces close approach events for whatever regime (LEO, MEO and GEO), and renders the probabilistic study and analysis of such events independent from the need of a CDM.
2. Computation and visualization of the probability dilution area in the two dimensional space of Kp and Ks scale factors used for the computation of the scaled probability of collision.
3. Computation of the scale factor interval in order to increase covariance realism, based on hypothesis testing with the Kolmogorov-Smirnov test (F.Laporte - CNES).
4. Computation of the effect of evasive manoeuvres, parametrized in time and velocity increment, on the scaled probability of collision.
I welcome you to the subtle but beautiful world of probabilities and inferential statistics or else how we managed to harness our ignorance to precise science!
Researched improvements on increasing efficiency of organic solar cells by utilizing and modifying the Purdue University researchers NanoMOS MATLAB simulations
https://nanohub.org/resources/1305?rev=1
Development of Seakeeping Test and Data Processing Systemijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
Time Domain Modelling of Optical Add-drop filter based on Microcavity Ring Re...iosrjce
IOSR Journal of Electronics and Communication Engineering(IOSR-JECE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of electronics and communication engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in electronics and communication engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Dynamics Behaviour of Multi Storeys Framed Structures by of Iterative Method AM Publications
Dynamics refers to the branch of mechanics that deals with the movement of objects and the forces that drive that movement. Structural analysis which covers the behaviour of structures subjected to dynamic (actions having high acceleration) loading. Dynamic loads include people, wind, waves, traffic, earthquakes, and blasts. Any structure can be subjected to dynamic loading. Dynamic analysis can be used to find dynamic displacements, time history, and the frequency content of the load. One analysis technique for calculating the linear response of structures to dynamic loading is a modal analysis. In modal analysis, we decompose the response of the structure into several vibration modes. A mode is defined by its frequency and shape. Structural engineers call the mode with the shortest frequency (the longest period) the fundamental mode. This paper presents a study on mode shape, inertia force, spring force and deflection of multi storied framed structures by comparison of stodola’s and Holzer method. This study involves in examination of theoretical investigations of multi storied framed structures. Overall four storey multi storied framed structures and two methods were analysed & comparison of all the mode shape, inertia force, spring force and deflection at the critical cross-section with same configuration loading by keeping all other parameters constant. The theoretical data are calculated using code IS 1893, IS 4326, IS 13920. The all storey mass and stiffens are analysed under the cantilever condition. The research project aims to provide which method is most accuracy to find the mode shape, spring force deflection and inertia force. The studies reveal that the theoretical investigations Stodola’s method is most accuracy compare to the Holzer method. The maximum mode shape, spring force, spring deflection and inertia force is 87.29%, 80 %, 89% and 72% is higher the Stodola’s method compare than Holzer method in same configuration.
In this day and age of connected living, it is critical for people to interface the wellbeing factors and health conditions into trends so as to picturize the state of health of an individual. In addition, it is essential to include the wearables and therapeutic gears to viably speedup up the treatment cycle. It is equally important to pull health records and scanned images from various systems which follow different standards and ensure that they interact appropriately. These interactions could either be driven from the clinics and hospitals, or performed as a part of awareness by the end users (patients and health conscious individuals). To understand these interactions, we have taken Diabetes management as our use case. Diabetes is turning into a lifestyle disease and hence is an ideal candidate since we need to monitor the health conditions of the patient continuously. The vital parameters of the body could either be monitored through medical devices and equipment, body sensors, mobile applications, or wearables.This paper analyses the solutions proposed so far for effective diabetes management using cloud technology. The paper also touches upon IoT-based solutions which could be used to treat chronic ailments from remote locations.
DESIGN, OPTIMIZATION AND DEVELOPMENT OF SOLAR THERMAL HEAT RECEIVER SYSTEM WI...Journal For Research
Against a backdrop of our world’s changing climate solar thermal power generation shows great potential to move global energy production away from fossil fuels to non-polluting sources. A parameter study was conducted based on the previous analysis to improve specific aspects of the initial design using a value of benefit analysis to evaluate the different design. This project focused on the design, analysis and verification of a high temperature solar receiver. Computational Fluid Dynamic (CFD) analysis of Radiation model is carried out with new geometry design of receiver. Discrete Transfer Radiation Model (DTRM) model is used for numerical simulation.
Similar to The SpaceDrive Project - First Results on EMDrive and Mach-Effect Thrusters (20)
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Gliese 12 b: A Temperate Earth-sized Planet at 12 pc Ideal for Atmospheric Tr...Sérgio Sacani
Recent discoveries of Earth-sized planets transiting nearby M dwarfs have made it possible to characterize the
atmospheres of terrestrial planets via follow-up spectroscopic observations. However, the number of such planets
receiving low insolation is still small, limiting our ability to understand the diversity of the atmospheric
composition and climates of temperate terrestrial planets. We report the discovery of an Earth-sized planet
transiting the nearby (12 pc) inactive M3.0 dwarf Gliese 12 (TOI-6251) with an orbital period (Porb) of 12.76 days.
The planet, Gliese 12 b, was initially identified as a candidate with an ambiguous Porb from TESS data. We
confirmed the transit signal and Porb using ground-based photometry with MuSCAT2 and MuSCAT3, and
validated the planetary nature of the signal using high-resolution images from Gemini/NIRI and Keck/NIRC2 as
well as radial velocity (RV) measurements from the InfraRed Doppler instrument on the Subaru 8.2 m telescope
and from CARMENES on the CAHA 3.5 m telescope. X-ray observations with XMM-Newton showed the host
star is inactive, with an X-ray-to-bolometric luminosity ratio of log 5.7 L L X bol » - . Joint analysis of the light
curves and RV measurements revealed that Gliese 12 b has a radius of 0.96 ± 0.05 R⊕,a3σ mass upper limit of
3.9 M⊕, and an equilibrium temperature of 315 ± 6 K assuming zero albedo. The transmission spectroscopy metric
(TSM) value of Gliese 12 b is close to the TSM values of the TRAPPIST-1 planets, adding Gliese 12 b to the small
list of potentially terrestrial, temperate planets amenable to atmospheric characterization with JWST.
Gliese 12 b, a temperate Earth-sized planet at 12 parsecs discovered with TES...Sérgio Sacani
We report on the discovery of Gliese 12 b, the nearest transiting temperate, Earth-sized planet found to date. Gliese 12 is a
bright (V = 12.6 mag, K = 7.8 mag) metal-poor M4V star only 12.162 ± 0.005 pc away from the Solar system with one of the
lowest stellar activity levels known for M-dwarfs. A planet candidate was detected by TESS based on only 3 transits in sectors
42, 43, and 57, with an ambiguity in the orbital period due to observational gaps. We performed follow-up transit observations
with CHEOPS and ground-based photometry with MINERVA-Australis, SPECULOOS, and Purple Mountain Observatory,
as well as further TESS observations in sector 70. We statistically validate Gliese 12 b as a planet with an orbital period of
12.76144 ± 0.00006 d and a radius of 1.0 ± 0.1 R⊕, resulting in an equilibrium temperature of ∼315 K. Gliese 12 b has excellent
future prospects for precise mass measurement, which may inform how planetary internal structure is affected by the stellar
compositional environment. Gliese 12 b also represents one of the best targets to study whether Earth-like planets orbiting cool
stars can retain their atmospheres, a crucial step to advance our understanding of habitability on Earth and across the galaxy.
The importance of continents, oceans and plate tectonics for the evolution of...Sérgio Sacani
Within the uncertainties of involved astronomical and biological parameters, the Drake Equation
typically predicts that there should be many exoplanets in our galaxy hosting active, communicative
civilizations (ACCs). These optimistic calculations are however not supported by evidence, which is
often referred to as the Fermi Paradox. Here, we elaborate on this long-standing enigma by showing
the importance of planetary tectonic style for biological evolution. We summarize growing evidence
that a prolonged transition from Mesoproterozoic active single lid tectonics (1.6 to 1.0 Ga) to modern
plate tectonics occurred in the Neoproterozoic Era (1.0 to 0.541 Ga), which dramatically accelerated
emergence and evolution of complex species. We further suggest that both continents and oceans
are required for ACCs because early evolution of simple life must happen in water but late evolution
of advanced life capable of creating technology must happen on land. We resolve the Fermi Paradox
(1) by adding two additional terms to the Drake Equation: foc
(the fraction of habitable exoplanets
with significant continents and oceans) and fpt
(the fraction of habitable exoplanets with significant
continents and oceans that have had plate tectonics operating for at least 0.5 Ga); and (2) by
demonstrating that the product of foc
and fpt
is very small (< 0.00003–0.002). We propose that the lack
of evidence for ACCs reflects the scarcity of long-lived plate tectonics and/or continents and oceans on
exoplanets with primitive life.
A Giant Impact Origin for the First Subduction on EarthSérgio Sacani
Hadean zircons provide a potential record of Earth's earliest subduction 4.3 billion years ago. Itremains enigmatic how subduction could be initiated so soon after the presumably Moon‐forming giant impact(MGI). Earlier studies found an increase in Earth's core‐mantle boundary (CMB) temperature due to theaccumulation of the impactor's core, and our recent work shows Earth's lower mantle remains largely solid, withsome of the impactor's mantle potentially surviving as the large low‐shear velocity provinces (LLSVPs). Here,we show that a hot post‐impact CMB drives the initiation of strong mantle plumes that can induce subductioninitiation ∼200 Myr after the MGI. 2D and 3D thermomechanical computations show that a high CMBtemperature is the primary factor triggering early subduction, with enrichment of heat‐producing elements inLLSVPs as another potential factor. The models link the earliest subduction to the MGI with implications forunderstanding the diverse tectonic regimes of rocky planets.
Climate extremes likely to drive land mammal extinction during next supercont...Sérgio Sacani
Mammals have dominated Earth for approximately 55 Myr thanks to their
adaptations and resilience to warming and cooling during the Cenozoic. All
life will eventually perish in a runaway greenhouse once absorbed solar
radiation exceeds the emission of thermal radiation in several billions of
years. However, conditions rendering the Earth naturally inhospitable to
mammals may develop sooner because of long-term processes linked to
plate tectonics (short-term perturbations are not considered here). In
~250 Myr, all continents will converge to form Earth’s next supercontinent,
Pangea Ultima. A natural consequence of the creation and decay of Pangea
Ultima will be extremes in pCO2 due to changes in volcanic rifting and
outgassing. Here we show that increased pCO2, solar energy (F⨀;
approximately +2.5% W m−2 greater than today) and continentality (larger
range in temperatures away from the ocean) lead to increasing warming
hostile to mammalian life. We assess their impact on mammalian
physiological limits (dry bulb, wet bulb and Humidex heat stress indicators)
as well as a planetary habitability index. Given mammals’ continued survival,
predicted background pCO2 levels of 410–816 ppm combined with increased
F⨀ will probably lead to a climate tipping point and their mass extinction.
The results also highlight how global landmass configuration, pCO2 and F⨀
play a critical role in planetary habitability.
Constraints on Neutrino Natal Kicks from Black-Hole Binary VFTS 243Sérgio Sacani
The recently reported observation of VFTS 243 is the first example of a massive black-hole binary
system with negligible binary interaction following black-hole formation. The black-hole mass (≈10M⊙)
and near-circular orbit (e ≈ 0.02) of VFTS 243 suggest that the progenitor star experienced complete
collapse, with energy-momentum being lost predominantly through neutrinos. VFTS 243 enables us to
constrain the natal kick and neutrino-emission asymmetry during black-hole formation. At 68% confidence
level, the natal kick velocity (mass decrement) is ≲10 km=s (≲1.0M⊙), with a full probability distribution
that peaks when ≈0.3M⊙ were ejected, presumably in neutrinos, and the black hole experienced a natal
kick of 4 km=s. The neutrino-emission asymmetry is ≲4%, with best fit values of ∼0–0.2%. Such a small
neutrino natal kick accompanying black-hole formation is in agreement with theoretical predictions.
Detectability of Solar Panels as a TechnosignatureSérgio Sacani
In this work, we assess the potential detectability of solar panels made of silicon on an Earth-like
exoplanet as a potential technosignature. Silicon-based photovoltaic cells have high reflectance in the
UV-VIS and in the near-IR, within the wavelength range of a space-based flagship mission concept
like the Habitable Worlds Observatory (HWO). Assuming that only solar energy is used to provide
the 2022 human energy needs with a land cover of ∼ 2.4%, and projecting the future energy demand
assuming various growth-rate scenarios, we assess the detectability with an 8 m HWO-like telescope.
Assuming the most favorable viewing orientation, and focusing on the strong absorption edge in the
ultraviolet-to-visible (0.34 − 0.52 µm), we find that several 100s of hours of observation time is needed
to reach a SNR of 5 for an Earth-like planet around a Sun-like star at 10pc, even with a solar panel
coverage of ∼ 23% land coverage of a future Earth. We discuss the necessity of concepts like Kardeshev
Type I/II civilizations and Dyson spheres, which would aim to harness vast amounts of energy. Even
with much larger populations than today, the total energy use of human civilization would be orders of
magnitude below the threshold for causing direct thermal heating or reaching the scale of a Kardashev
Type I civilization. Any extraterrrestrial civilization that likewise achieves sustainable population
levels may also find a limit on its need to expand, which suggests that a galaxy-spanning civilization
as imagined in the Fermi paradox may not exist.
Jet reorientation in central galaxies of clusters and groups: insights from V...Sérgio Sacani
Recent observations of galaxy clusters and groups with misalignments between their central AGN jets
and X-ray cavities, or with multiple misaligned cavities, have raised concerns about the jet – bubble
connection in cooling cores, and the processes responsible for jet realignment. To investigate the
frequency and causes of such misalignments, we construct a sample of 16 cool core galaxy clusters and
groups. Using VLBA radio data we measure the parsec-scale position angle of the jets, and compare
it with the position angle of the X-ray cavities detected in Chandra data. Using the overall sample
and selected subsets, we consistently find that there is a 30% – 38% chance to find a misalignment
larger than ∆Ψ = 45◦ when observing a cluster/group with a detected jet and at least one cavity. We
determine that projection may account for an apparently large ∆Ψ only in a fraction of objects (∼35%),
and given that gas dynamical disturbances (as sloshing) are found in both aligned and misaligned
systems, we exclude environmental perturbation as the main driver of cavity – jet misalignment.
Moreover, we find that large misalignments (up to ∼ 90◦
) are favored over smaller ones (45◦ ≤ ∆Ψ ≤
70◦
), and that the change in jet direction can occur on timescales between one and a few tens of Myr.
We conclude that misalignments are more likely related to actual reorientation of the jet axis, and we
discuss several engine-based mechanisms that may cause these dramatic changes.
The solar dynamo begins near the surfaceSérgio Sacani
The magnetic dynamo cycle of the Sun features a distinct pattern: a propagating
region of sunspot emergence appears around 30° latitude and vanishes near the
equator every 11 years (ref. 1). Moreover, longitudinal flows called torsional oscillations
closely shadow sunspot migration, undoubtedly sharing a common cause2. Contrary
to theories suggesting deep origins of these phenomena, helioseismology pinpoints
low-latitude torsional oscillations to the outer 5–10% of the Sun, the near-surface
shear layer3,4. Within this zone, inwardly increasing differential rotation coupled with
a poloidal magnetic field strongly implicates the magneto-rotational instability5,6,
prominent in accretion-disk theory and observed in laboratory experiments7.
Together, these two facts prompt the general question: whether the solar dynamo is
possibly a near-surface instability. Here we report strong affirmative evidence in stark
contrast to traditional models8 focusing on the deeper tachocline. Simple analytic
estimates show that the near-surface magneto-rotational instability better explains
the spatiotemporal scales of the torsional oscillations and inferred subsurface
magnetic field amplitudes9. State-of-the-art numerical simulations corroborate these
estimates and reproduce hemispherical magnetic current helicity laws10. The dynamo
resulting from a well-understood near-surface phenomenon improves prospects
for accurate predictions of full magnetic cycles and space weather, affecting the
electromagnetic infrastructure of Earth.
Extensive Pollution of Uranus and Neptune’s Atmospheres by Upsweep of Icy Mat...Sérgio Sacani
In the Nice model of solar system formation, Uranus and Neptune undergo an orbital upheaval,
sweeping through a planetesimal disk. The region of the disk from which material is accreted by
the ice giants during this phase of their evolution has not previously been identified. We perform
direct N-body orbital simulations of the four giant planets to determine the amount and origin of solid
accretion during this orbital upheaval. We find that the ice giants undergo an extreme bombardment
event, with collision rates as much as ∼3 per hour assuming km-sized planetesimals, increasing the
total planet mass by up to ∼0.35%. In all cases, the initially outermost ice giant experiences the
largest total enhancement. We determine that for some plausible planetesimal properties, the resulting
atmospheric enrichment could potentially produce sufficient latent heat to alter the planetary cooling
timescale according to existing models. Our findings suggest that substantial accretion during this
phase of planetary evolution may have been sufficient to impact the atmospheric composition and
thermal evolution of the ice giants, motivating future work on the fate of deposited solid material.
Exomoons & Exorings with the Habitable Worlds Observatory I: On the Detection...Sérgio Sacani
The highest priority recommendation of the Astro2020 Decadal Survey for space-based astronomy
was the construction of an observatory capable of characterizing habitable worlds. In this paper series
we explore the detectability of and interference from exomoons and exorings serendipitously observed
with the proposed Habitable Worlds Observatory (HWO) as it seeks to characterize exoplanets, starting
in this manuscript with Earth-Moon analog mutual events. Unlike transits, which only occur in systems
viewed near edge-on, shadow (i.e., solar eclipse) and lunar eclipse mutual events occur in almost every
star-planet-moon system. The cadence of these events can vary widely from ∼yearly to multiple events
per day, as was the case in our younger Earth-Moon system. Leveraging previous space-based (EPOXI)
lightcurves of a Moon transit and performance predictions from the LUVOIR-B concept, we derive
the detectability of Moon analogs with HWO. We determine that Earth-Moon analogs are detectable
with observation of ∼2-20 mutual events for systems within 10 pc, and larger moons should remain
detectable out to 20 pc. We explore the extent to which exomoon mutual events can mimic planet
features and weather. We find that HWO wavelength coverage in the near-IR, specifically in the 1.4 µm
water band where large moons can outshine their host planet, will aid in differentiating exomoon signals
from exoplanet variability. Finally, we predict that exomoons formed through collision processes akin
to our Moon are more likely to be detected in younger systems, where shorter orbital periods and
favorable geometry enhance the probability and frequency of mutual events.
Emergent ribozyme behaviors in oxychlorine brines indicate a unique niche for...Sérgio Sacani
Mars is a particularly attractive candidate among known astronomical objects
to potentially host life. Results from space exploration missions have provided
insights into Martian geochemistry that indicate oxychlorine species, particularly perchlorate, are ubiquitous features of the Martian geochemical landscape. Perchlorate presents potential obstacles for known forms of life due to
its toxicity. However, it can also provide potential benefits, such as producing
brines by deliquescence, like those thought to exist on present-day Mars. Here
we show perchlorate brines support folding and catalysis of functional RNAs,
while inactivating representative protein enzymes. Additionally, we show
perchlorate and other oxychlorine species enable ribozyme functions,
including homeostasis-like regulatory behavior and ribozyme-catalyzed
chlorination of organic molecules. We suggest nucleic acids are uniquely wellsuited to hypersaline Martian environments. Furthermore, Martian near- or
subsurface oxychlorine brines, and brines found in potential lifeforms, could
provide a unique niche for biomolecular evolution.
Continuum emission from within the plunging region of black hole discsSérgio Sacani
The thermal continuum emission observed from accreting black holes across X-ray bands has the potential to be leveraged as a
powerful probe of the mass and spin of the central black hole. The vast majority of existing ‘continuum fitting’ models neglect
emission sourced at and within the innermost stable circular orbit (ISCO) of the black hole. Numerical simulations, however,
find non-zero emission sourced from these regions. In this work, we extend existing techniques by including the emission
sourced from within the plunging region, utilizing new analytical models that reproduce the properties of numerical accretion
simulations. We show that in general the neglected intra-ISCO emission produces a hot-and-small quasi-blackbody component,
but can also produce a weak power-law tail for more extreme parameter regions. A similar hot-and-small blackbody component
has been added in by hand in an ad hoc manner to previous analyses of X-ray binary spectra. We show that the X-ray spectrum
of MAXI J1820+070 in a soft-state outburst is extremely well described by a full Kerr black hole disc, while conventional
models that neglect intra-ISCO emission are unable to reproduce the data. We believe this represents the first robust detection of
intra-ISCO emission in the literature, and allows additional constraints to be placed on the MAXI J1820 + 070 black hole spin
which must be low a• < 0.5 to allow a detectable intra-ISCO region. Emission from within the ISCO is the dominant emission
component in the MAXI J1820 + 070 spectrum between 6 and 10 keV, highlighting the necessity of including this region. Our
continuum fitting model is made publicly available.
WASP-69b’s Escaping Envelope Is Confined to a Tail Extending at Least 7 RpSérgio Sacani
Studying the escaping atmospheres of highly irradiated exoplanets is critical for understanding the physical
mechanisms that shape the demographics of close-in planets. A number of planetary outflows have been observed
as excess H/He absorption during/after transit. Such an outflow has been observed for WASP-69b by multiple
groups that disagree on the geometry and velocity structure of the outflow. Here, we report the detection of this
planet’s outflow using Keck/NIRSPEC for the first time. We observed the outflow 1.28 hr after egress until the
target set, demonstrating the outflow extends at least 5.8 × 105 km or 7.5 Rp This detection is significantly longer
than previous observations, which report an outflow extending ∼2.2 planet radii just 1 yr prior. The outflow is
blueshifted by −23 km s−1 in the planetary rest frame. We estimate a current mass-loss rate of 1 M⊕ Gyr−1
. Our
observations are most consistent with an outflow that is strongly sculpted by ram pressure from the stellar wind.
However, potential variability in the outflow could be due to time-varying interactions with the stellar wind or
differences in instrumental precision.
X-rays from a Central “Exhaust Vent” of the Galactic Center ChimneySérgio Sacani
Using deep archival observations from the Chandra X-ray Observatory, we present an analysis of
linear X-ray-emitting features located within the southern portion of the Galactic center chimney,
and oriented orthogonal to the Galactic plane, centered at coordinates l = 0.08◦
, b = −1.42◦
. The
surface brightness and hardness ratio patterns are suggestive of a cylindrical morphology which may
have been produced by a plasma outflow channel extending from the Galactic center. Our fits of the
feature’s spectra favor a complex two-component model consisting of thermal and recombining plasma
components, possibly a sign of shock compression or heating of the interstellar medium by outflowing
material. Assuming a recombining plasma scenario, we further estimate the cooling timescale of this
plasma to be on the order of a few hundred to thousands of years, leading us to speculate that a
sequence of accretion events onto the Galactic Black Hole may be a plausible quasi-continuous energy
source to sustain the observed morphology
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Body fluids_tonicity_dehydration_hypovolemia_hypervolemia.pptx
The SpaceDrive Project - First Results on EMDrive and Mach-Effect Thrusters
1. See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/325177082
The SpaceDrive Project - First Results on EMDrive and Mach-Effect
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The SpaceDrive Project – First Results on EMDrive and Mach-Effect Thrusters
BARCELO RENACIMIENTO HOTEL, SEVILLE, SPAIN / 14 – 18 MAY 2018
Martin Tajmar(1)
, Matthias Kößling(2)
, Marcel Weikert(3)
and Maxime Monette(4)
(1-4) Institute of Aerospace Engineering, Technische Universität Dresden, Marschnerstrasse 32, 01324
Dresden, Germany, Email: martin.tajmar@tu-dresden.de
KEYWORDS: Breakthrough Propulsion, Propellant-
less Propulsion, EMDrive, Mach-Effect Thruster
ABSTRACT:
Propellantless propulsion is believed to be the
best option for interstellar travel. However, photon
rockets or solar sails have thrusts so low that maybe
only nano-scaled spacecraft may reach the next star
within our lifetime using very high-power laser
beams. Following into the footsteps of earlier
breakthrough propulsion programs, we are
investigating different concepts based on non-
classical/revolutionary propulsion ideas that claim to
be at least an order of magnitude more efficient in
producing thrust compared to photon rockets. Our
intention is to develop an excellent research
infrastructure to test new ideas and measure thrusts
and/or artefacts with high confidence to determine if
a concept works and if it does how to scale it up. At
present, we are focusing on two possible
revolutionary concepts: The EMDrive and the Mach-
Effect Thruster. The first concept uses microwaves in
a truncated cone-shaped cavity that is claimed to
produce thrust. Although it is not clear on which
theoretical basis this can work, several experimental
tests have been reported in the literature, which
warrants a closer examination. The second concept
is believed to generate mass fluctuations in a piezo-
crystal stack that creates non-zero time-averaged
thrusts. Here we are reporting first results of our
improved thrust balance as well as EMDrive and
Mach-Effect thruster models. Special attention is
given to the investigation and identification of error
sources that cause false thrust signals. Our results
show that the magnetic interaction from not
sufficiently shielded cables or thrusters are a major
factor that needs to be taken into account for proper
µN thrust measurements for these type of devices.
1. INTRODUCTION
Interstellar travel is one of mankind’s biggest
dream and challenge. Rockets routinely put
spacecraft into Earth’s orbit, however Tsiolkovsky’s
equation puts a strong limit on the achievable v if
onboard propellant is used, even using advanced
materials and futuristic engines. For example, even
nuclear propulsion with a specific impulse of 10,000
s or more (nuclear pulse, combined electric/nuclear,
fusion propulsion, etc.) requires a propellant mass on
the order of the mass of our sun to propel a
spacecraft to our nearest star within our lifetime [1].
Recent efforts therefore concentrate on using
propellantless laser propulsion. For example, the
proposed Breakthrough Starshot project plans to use
a 100 GW laser beam to accelerate a nano-
spacecraft with the mass of a few grams to reach our
closest neighbouring star Proxima Centauri in around
20 years [2]. The technical challenges (laser power,
steering, communication, etc.) are enormous but
maybe not impossible [3]. Such ideas stretch the
edge of our current technology. However, it is
obvious that we need a radically new approach if we
ever want to achieve interstellar flight with spacecraft
in size similar to the ones that we use today. In the
1990s, NASA started its Breakthrough Propulsion
Physics Program, which organized workshops,
conferences and funded multiple projects to look for
high-risk/high-payoff ideas [4]. The project
culminated in a book that summarized the ideas
studied and presented a roadmap with unexplored
areas to follow up [5].
Within the SpaceDrive project [6], we are currently
assessing the two most prominent thruster
candidates that promise propellantless propulsion
much better than photon rockets: The so-called
EMDrive and the Mach-Effect thruster. In addition, we
are performing complementary experiments that can
provide additional insights into the thrusters under
investigation or open up new concepts. In order to
properly test the thruster candidates, we are
constantly improving our thrust balance facility as
well as checking for thruster-environment
interactions that can lead to false thrust
measurements.
Our goal is to falsify if these thrusters work as
claimed and to identify and understand the working
mechanisms that could enable to upscale them
towards flight applications. This paper will review the
first results so far.
2. SpaceDrive Project
2.1 Thrust Balance
Testing of propellantless propulsion concepts
requires a highly sophisticated thrust balance that
must be able to reliably detect very small thrust with
a resolution down to the nano-Newton range, block
electromagnetic interactions as much as possible
and limit any balance-vacuum chamber wall
interactions. Vibration and thermal expansion/drifts
are the two most important artefacts that must be
carefully isolated to obtain reliable measurements.
3. SP2018_016
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The basis for our measurements is a torsion
balance in our large vacuum chamber (0.9 m
diameter, 1.5 m length) that has undergone various
improvements over more than 4 years. A thrust
produces an angular displacement that can be
measurement by a laser interferometer. We use two
C-flex E-20 torsion springs with a high enough
sensitivity (2x0.0033 Nm/) to achieve sub-µN
resolution while supporting enough weight on the
balance arms. The vacuum chamber uses a vibration
isolated Edwards XDS35i scroll pump and a Pfeiffer
2300 L turbo pump to reach a vacuum down to the
10-7 mbar range. For the tests on the EMDrive and
Mach-Effect thruster, only the scroll pump was used
with a vacuum level of 10-2 mbar, which was sufficient
to suppress buoyancy for quicker turnaround times.
The vacuum chamber is fixed to a separate concrete
block that is mounted with vibration isolation to
decouple it from the vibrations in the building’s
foundation (see Fig. 1). Based on our prior
experiments with Mach-Effect and EMDrive
thrusters, an upgraded balance has been built with
the following features:
- A total weight of up to 25 kg of thruster and
electronics can be installed on the balance.
There are two separately-shielded boxes on
each side: one for the thruster assembly and one
for the electronics and data acquisition.
- Thrust noise reduced to the nano-Newton range
with a sub-Nanonewton resolution. We use the
attocube IDS 3010 laser displacement sensor
with pm resolution to digitally read out the
balance position.
- Variable damping using eddy-currents and
permanent magnets. A stepper motor can
change the position of a copper disc to adapt the
strength of damping.
- Stepper motors to level the balance once it is
completely set-up inside the vacuum chamber.
- Stepper motors to change the orientation of the
thruster. This enables us to investigate e.g. shifts
in the center of gravity due to thermal expansion
by changing the thruster direction from forward to
backward and observing the change in the thrust
measurement. All this can be done inside the
vacuum chamber without breaking vacuum and
changing any cables that can influence the
analysis.
- Two different calibration techniques, one using a
voice coil and one using electrostatic combs that
provide constant thrusts by applying a defined
current (coil) or voltage (comb) which was
calibrated with a dedicated setup using a
Sartorius AX224 balance.
- Complete shielding of the balance arm and
thruster/electronics boxes using high
permeability Mu-metal.
- Wireless control of experiment by on-board data
acquisition using either Weeder modules or a
LabJack T7 Pro using an infrared serial port. This
allows analog input/output, digital control of
relays as well as temperature measurements on
the balance. In addition, we added infrared
cameras that can detect overheating of the
electronics and the thruster.
- Four pairs of liquid-metal-contacts with twisted,
paired cables to supply the balance and
experiments with power and other data signals
(see Fig. 2).
- LabView program that can operate and control
the complete vacuum facility, thrust balance and
experiments. A script language is used to
automate the whole experiment, from calibration
to measurement. This procedure ensures
repeatable measurements and allows to check
the validity of the balance calibration and perform
signal averaging and filter operation to obtain
very low noise signals.
A picture of the vacuum chamber as well as the
schematic of the balance is shown in Fig. 1. All
calibration and thruster experiments are executed
using profiles with a down-time (sector 1), a ramp-up
(sector 2), a constant thrust (sector 3), a ramp-down
(sector 4) and again down-time (sector 5) interval.
Each profile can be checked individually and data
processing like drift compensation or filtering can be
applied. Drift compensation can be done with many
different options like using a linear or polynomial fit
through sector 1 and 5 and subtraction from the
profile. Since the thrusters heated up during testing,
a thermal drift compensation technique was used
where first a linear fit is performed in sector 1 and 5
and a straight line is used to connect the end of sector
1 to the beginning of sector 5 to account for any
thermal drifts (see Fig. 5). Profiles can be repeated
many times and a signal averaged plot can be
computed that can drastically reduce noise and
increase signal confidence.
An example of a one µN calibration pulse is shown
in Fig. 3 using our voice coil. The low noise (<10 nN)
as well as the damping and drift elimination is clearly
evident. We performed calibration pulses along a
wide range with small steps as shown in Fig. 4 that
shows the high linearity of our balance. This figure
also shows how the calibration constant (µN/µm)
changes for different setups with different weights. A
calibration is automatically performed before and
after each thrust measurement to check for any
changes in the balance sensitivity.
2.1 EMDrive
The EMDrive is a concept developed by Shawyer
[7] in which microwaves are directed into a truncated
resonator cavity/frustum which is claimed to produce
thrust. He believes that the radiation pressure is
different at the small and large ends which results in
a net thrust force [8]. This was highly criticized as not
being compatible with electromagnetism and
conservation laws [9]. Alternative theories have
appeared [10]–[12], however, the community
4. SP2018_016
Page 3
remains highly sceptical on the theoretical grounds of
this concept.
On the other hand, there is a significant amount of
experimental data available with tests both on a
normal/knife-edge [13],[14] as well as on a torsion
balance [15]–[17]. Initial concern concentrated on
buoyancy effects due to testing in air, however, the
more recent tests in high vacuum [17], especially
NASA’s latest test results by White et al [16] revealed
that air is not an issue. Several experimental artefacts
still need to be examined and higher quality thrust
data must be obtained in order to validate the
production of thrust. Thermal drifts were especially
significant in the latest reported test by White et al.
[16] and possible magnetic interaction with feeding
cables has yet to be assessed.
We built a frustum cavity with the same inner
dimensions as in White et al [16], however, instead of
hand-cut copper sheets and copper plated PCBs, our
cavity geometry was manufactured from 1.5 mm thick
copper sheets that were pressed into the correct
geometry (see Fig. 6). Afterwards, the inner surfaces
were polished. We used standard SMA/N-Type
connectors throughout all components. A picture of
our loop antenna (1.5 mm wire, 15 mm radius) is also
shown in Fig. 6 as well as the complete EMDrive with
cavity and all related electronics on one side of the
torsion balance. Because of the size of the cavity, we
could not encapsulate it yet with Mu-metal sheets to
reduce possible magnetic interactions. This will be
crucial in the next step as we will explain below.
The resonance frequencies and Q-factors of the
cavity were analysed using an Anritsu MS46121B
vector network analyser. Using a Maury 1878B 3-
stub tuner, we matched a frequency of 1865 MHz and
obtained Q-factors from 20,000 – 300,000+
(unloaded) depending on the peak (see Fig. 7). This
is similar and even higher than the values reported
by White et al [16] and should lead to at least similar
thrust values if not more as the Q-factor is believed
to be directly related to the generated thrust [7].
COMSOL simulations were carried out to simulate
the generated modes within the cavity and to find the
optimum position for the antenna (see Fig. 8).
The EMDrive setup is shown in Fig. 9 which
consists of a frequency generator/oscillator (Mini-
Circuits ZX95-2041-S+), a voltage-controlled
attenuator (Mini-Circuits ZX73-2500-S+), a 50 W
amplifier (RF Systems EMPower 1164), a bi-
directional coupler (Mini-Circuits ZGBDC35-93HP+)
with power-meters for input and reflected output
(Mini-Circuits ZX47-40-S+), an optional fixed 40 dB
attenuator (Mini-Circuits BW-40N100W+), the Maury
3-stub tuner and the cavity. All these components
could be operated in vacuum without modification (a
small venting hole was present in the cavity and one
screw was removed from the Mini-Circuits
components), however, we were cautiously operating
them only up to a power of 2 Watts to prohibit
overheating (several thermocouples are used to
monitor the temperature). The optional 40 dB
attenuator allows to reduce the power by a factor of
10,000 that goes into the cavity without changing
cables or setup. This provides a powerful “zero-
thrust” measurement capability. Our software
features resonance frequency tracking to
compensate for frequency shifts during operation.
Using the stepper motor, we could rotate the
thruster on our balance such that it points in different
directions. In our setup, 0° direction means a positive
thrust direction (going from the large back area on the
cavity to the smaller front area), 180° direction means
a reversed or negative thrust direction and 90° means
that the thruster points parallel to the balance arm,
which should result in zero thrust.
Fig. 10 shows thrust measurements for our
EMDrive in all directions with around 4 µN at an
amplifier power level of 2 Watts, which corresponds
to an amplifier current of around 2.5 A. The maximum
temperature on the amplifier was going up to 75
degrees. The Q factor in this case was 50,000
(unloaded). This leads to a thrust-to-power ratio of
around 2 mN/kW, which is nearly double compared
to White et al [16] who measured 1.3 mN/kW for a Q
factor of 40,900 (their absolute thrust value was 80
µN for 60 W of power). The thrust direction also
seems to reverse for the 180° direction. However, at
90° we see a similar thrust as in the 180° direction,
where we should expect zero thrust. Even more
importantly, if we keep the 0° direction but use the 40
dB attenuator to reduce the power that goes into the
cavity by 5 orders of magnitude, the thrust signal
nearly remains the same as without the 40 dB
attenuator.
This clearly indicates that the “thrust” is not
coming from the EMDrive but from some
electromagnetic interaction. Although we used
twisted or coaxial cables as much as possible, some
magnetic fields will eventually leak through our
cables and connectors. Considering the magnetic
field strength of the Earth’s magnetic field of 48 µT
with an inclination of 70° in middle Europe, a few
centimeters of cables and a current of 2 A (similar to
what is needed to power the amplifier), we obtain
Lorentz forces of a few µN, which is similar to our
observed “thrust” values. We therefore suspect, that
the interaction of the power feeding for the amplifier
with the Earth’s magnetic field masked any real
thrusts that could be below our observed value. In a
next setup, we are enlarging our experiment box such
that the cavity and amplifier configuration can be
completely shielded with Mu-metal sheets to greatly
reduce this artefact. However, such shielding was not
present in any of the previous tests (e.g. in White et
al [16]) which should be carefully re-analysed [18].
Note that we did not implement a dielectric disc
in our cavity so far which was used in the
configuration from White et al [16], although positive
tests were claimed to have been carried without such
discs too. After our setup improvement, we will try a
dielectric disc configuration, different geometries as
well as higher power levels.
5. SP2018_016
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2.2 Mach-Effect Thruster
The second concept to be studied in detail is the
so-called Mach-Effect thruster which is being
developed by J.F. Woodward since the 1990s and
more recently by H. Fearn [19]–[22]. It is based on
one interpretation of Mach’s principle (inertia here is
due to mass out there), that inertial mass is due to the
gravitational interaction with the whole universe [23].
Woodward and others showed that linearized general
relativity theory with time-varying solutions and
Sciama’s analysis altogether leads to mass
fluctuations that can be up to 11 orders of magnitude
higher for typical devices than classically expected
from E=m.c² [24].
In the Mach-Effect thruster, a stack of clamped
piezo crystals is excited using a frequency in the tens
of kHz range. According to Woodward, this energy
oscillations leads to transient Machian-mass
variations that can lead to time-averaged stationary
thrusts if they are properly pushed and pulled with the
correct frequency and phase. This is believed to
happen thanks to the piezoelectric and
electrostrictive material properties of piezo crystals.
Although at much smaller amplitudes, electrostriction
happens at twice the applied frequency and at a 90°
phase shift, which is required for stationary thrust
[22],[24]. A large brass reaction mass can amplify this
effect. A schematic sketch of the thruster as well as
an actual thruster and a corresponding ANSYS
model is shown in Fig. 11. We are working on
analytical as well as finite element models to
accurately predict the oscillation movements on the
thruster (verified using laser vibrometry) in order to
predict and enhance the thrust produced.
In order to operate the thruster, we built an
amplifier based on the Apex PA04 amplifier that has
a frequency range of up to 180 kHz (measured in our
setup), 150 W and a voltage capability of 150 Vpp
(voltage and power may be doubled using two
amplifiers in bridge mode). This is significantly better
compared to the audio amplifiers used so far that cut
the power close to the thruster operating frequencies
(35 kHz) [22],[25].
Fig. 12 shows the frequency response spectrum
for a recent thruster supplied to us by Woodard and
Fearn. The first resonance frequency is at 31 kHz.
Our software can control the amplifier with various
options such as using arbitrary waveforms (sine wave
or e.g. mixed signals with single- and double-
frequency signals at a proper phase shift) using a
Picoscope 2405A oscilloscope that has an arbitrary
waveform output. The current, voltage and phase
signals are read back into the computer. Most
importantly, we implemented a tracker that adapts
the frequency e.g. to track for maximum current
(=power). We can therefore operate always at
resonance even if the thruster warms up during
operation, which causes resonance frequency shifts.
The thruster was mounted inside the
measurement box with Mu-metal shielding. The
amplifier electronics were outside, and a liquid-metal
feedthrough was used to power the thruster on the
balance. Fig. 13 shows thrust results in all three
directions (0°, 90° and 180°) for 150 Vpp and an
applied sine wave at 31 kHz in vacuum. The apparent
thrust has a value of 0.6 µN and indeed reverses for
180° and moreover also vanishes at 90° as expected.
However, when we moved the thruster box back to
the 0° direction and manually flipped only the thruster
to 180°, while leaving all power cables the same, the
thruster signal remained the same as in the 0°
direction. This again indicates that there must be
some electromagnetic interaction or thermally
induced center of mass shift that is masking any real
thrust value.
Woodward measured a steady thrust with this
thruster of around -1.2 µN for 400 Vpp as well as
large switching thrust transients during on-off.
Previous data suggests a V4 scaling of thrust with
applied voltage [21]. We therefore expect only 0.02
µN which may be present in our thrust data but
masked by electromagnetic/thermal issues. In a next
step, we need to increase our voltage and reduce our
thermal and electromagnetic interactions to safely
assess this thrust range.
3. Conclusions
The SpaceDrive project aims at developing
cutting-edge measurement equipment to thoroughly
test the latest EMDrive and Mach-Effect thruster
models, the two most promising revolutionary
thruster concepts that are presently under
investigation at various labs. Our thrust balances
shall provide the necessary resolution and
investigate electromagnetic and thermal artefacts to
obtain reliable measurements in order to confirm or
refute the claimed thrusts.
First measurement campaigns were carried out
with both thruster models reaching thrust/thrust-to-
power levels comparable to claimed values.
However, we found that e.g. magnetic interaction
from twisted-pair cables and amplifiers with the
Earth’s magnetic field can be a significant error
source for EMDrives. We continue to improve our
measurement setup and thruster developments in
order to finally assess if any of these concepts is
viable and if it can be scaled up.
In addition, a number of complementary
experiments are carried out to investigate e.g.
Machian-mass variations with an alternative rotary
setup [6].
At least, SpaceDrive is an excellent educational
project by developing highly demanding test setups,
evaluating theoretical models and possible
experimental errors. It’s a great learning experience
with the possibility to find something that can drive
space exploration into its next generation.
Acknowledgements
We gratefully acknowledge the support for
SpaceDrive by the German National Space Agency
DLR (Deutsches Zentrum fuer Luft- und
6. SP2018_016
Page 5
Raumfahrttechnik) by funding from the Federal
Ministry of Economic Affairs and Energy (BMWi) by
approval from German Parliament (50RS1704). We
would also like to acknowledge the support from J.
Heisig, W. Stark, C. Holzapfel, J. Woodward and H.
Fearn for their contributions to the ongoing
experiments.
References
[1] Tajmar, M., Advanced Space Propulsion
Systems, Vienna: Springer Vienna, 2003.
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