Eucalyptus trees may translocate Au from mineral deposits and support the use of vegetation (biogeochemical) sampling in mineral exploration, particularly where thick sediments dominate. However, ...biogeochemistry has not been routinely adopted partly because biotic mechanisms of Au migration are poorly understood. For example, although Au has been previously measured in plant samples, there has been doubt as to whether it was truly absorbed rather than merely adsorbed on the plant surface as aeolian contamination. Here we show the first evidence of particulate Au within natural specimens of living biological tissue (not from laboratory experimentation). This observation conclusively demonstrates active biogeochemical adsorption of Au and provides insight into its behaviour in natural samples. The confirmation of biogeochemical adsorption of Au, and of a link with abiotic processes, promotes confidence in an emerging technique that may lead to future exploration success and maintain continuity of supply.
This paper proposes a switched-capacitor based single-phase five-level inverter configuration that operates under boost operation and generates a voltage that is more than the DC source voltage. The ...proposed five-level inverter uses a capacitor and boots the output voltage. In this proposed inverter, capacitor gets charged in parallel while it discharges in series connections so that output voltage may attain higher magnitude than the DC source voltage. Sinusoidal Pulse Width Modulation-based techniques are considered to produce the required gate pulses for operating the switching devices of the inverter. The five-level switched-capacitor inverter is combined with the PV system via DC-DC boost converters to extract the maximum power using MPPT algorithm. To verify its capability, the PV-based system is further integrated to the utility grid. The operation and performance of the suggested switched-capacitor inverter coupled with the grid-connected PV system are also analyzed by developing its model in MATLAB/Simulink environment.
In this paper, we evaluate several criteria for the detection of turbulent/non-turbulent interface using direct numerical simulation and particle image velocimetry data of an axisymmetric turbulent ...jet. The possibility of identifying the interface from information available in wholefield velocity data alone is also explored. The present results using a Concentration thresholding technique compare well against available results obtained using a similar detection criterion. It is noted that Concentration and Vorticity criteria are difficult to apply with standard PIV data and therefore a new criterion based on azimuthal vorticity and streamwise velocity—quantities available from such data, is proposed. The proposed criterion scores over previously employed criteria in terms of its simplicity of evaluation, and can possibly be applied to other flows not tested here. The instantaneous location of the interface as detected from the different criteria differs substantially. However, the conditionally averaged streamwise velocity, azimuthal vorticity, and Reynolds shear stress across the interface obtained from the new criterion, as well as from the previous criteria, agree reasonably well against available results. The present work further suggests that different criteria, even with slightly sub-optimal threshold value, can provide quantitatively similar ensemble-averaged results.
Recently, demands of the prefabricated tailor-welded blanks (TWBs) are being increased in the manufacturing of the structures of the aircraft panels. TWBs eliminate several operations of assembly ...process and reduce the consumption of material, time and cost. To manufacture the TWBs, friction stir welding process is gaining popularity because it reduces the common defects of the convention welding method. However, welding of similar and dissimilar material having different thicknesses is challenging by friction stir welding process. In this work, an attempt has been made to join the dissimilar material with different thickness ratios and also evaluate the performance of the weld joint with effect of input process parameters using surface response methodology. The experiments were conducted on the basis of Box–Behnken method design of experiments, in which three input factors are tool welding speed, rotation speed and tilt angle, and tensile strength of the joint is output response. Adequacy of the design of experiments is investigated by ANOVA analysis, and mathematical model is developed to determine the trend of the response surfaces of tensile strength to input factors. Additionally, microstructures of the weld joint are studied to analyze the material deposition process in the weld joint of the different thicknesses of the work piece material. This analysis shows that the tool tilt angle is one of the important factors among all input process parameters. The trend of the response surfaces of the tensile strength of the weld joint substantially varies on slight variation in the tool tilt angle. The highest tensile strength 302 MPa of the weld joint is obtained at 8
0
tool tilt angle, 900 rpm and 63 mm/min welding speed. The average grain size in stir zone of highest tensile strength weld joint is 6.01 μm, and lowest tensile strength weld joint is 13.99 μm.
Glacial sediments have been thoroughly integrated into mineral exploration protocols in the Northern hemisphere (e.g., Canada and Fennoscandia), but have received less attention in Australia. In ...Western Australia (WA), Permo-Carboniferous diamictites, buried by younger Cenozoic sediments, cover scattered areas that have potential to host gold and nickel mineralization, in the NE of the Yilgarn Craton. A systematic stratigraphic, mineralogical and geochemical study was undertaken to determine whether diamictites in the Agnew–Lawlers gold province have properties that may help target concealed mineralization. At the Agnew–Lawlers District, rocks intersected in 31 drill holes NE of the Waroonga gold mine, were interpreted in terms of lithological, textural and paleolandscape, mineralogical and geochemical variations to select the best sampling media for mineral exploration and provenance assessment. The paleotopographic variation, asymmetry of the depositional basin, polymictic composition, matrix-supported, mixed angular and rounded and poorly sorted texture of the diamictite clasts indicate mechanical dispersal from proximal and distal, heterogeneous source rocks. Ferromagnesian minerals, chromite, Cr-magnetite, magnetite and Ni–Cu–Fe sulfides are abundant in the diamictite close to mafic–ultramafic source rocks. Monazite, apatite, zircon and clasts derived from pyrite-bearing quartz veins increase in abundance in the diamictite close to the Waroonga shear zone that separates granitoid/gneiss terrain from the Scotty Creek metasediments. Ilmenite is extensively distributed in diamictites throughout the study area and its Mn content can be used to differentiate between felsic and mafic source rocks. Alteration of ilmenite to titanite, monazite to apatite and thorite, and replacement and fracture-filling of pentlandite to monazite suggest felsic, intrusive-related hydrothermal alteration of the source rocks prior to mechanical weathering. Late Paleozoic tropical weathering associated with oscillation of water table and icehouse to greenhouse climatic shift has created paleoredox fronts in the Permo-Carboniferous sequence. Below the redox fronts, diamictites are unweathered, rich in detrital sulfide and opaque oxide minerals and can be used in provenance studies and tracing mineralization. These characteristics of unweathered diamictite are the optimal sampling medium target for provenance studies and mineral exploration. These are cemented mainly by calcareous cement where they overlie mafic–ultramafic rocks and by pyrite cement where they overlie the Scotty Creek metasediments. Above the redox fronts, diamictites are variably weathered to ferruginous and bleached kaolinitic saprolites which are stable under oxidizing, circum-neutral conditions. Ferruginous diamictites are rich in recycled redox-sensitive elements derived from oxidation of ferromagnesian, sulfide and opaque oxide heavy minerals. These weathering features can be used to identify weathered diamictite for sampling for hydromorphic metal dispersion studies.
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•Areas of deep transported cover are frustrating for mineral exploration.•Permo-Carboniferous diamictites have been investigated as a sampling medium for mineral exploration.•Heavy minerals of the unweathered diamictites are good for studying provenance.•Weathered diamictites can be used to show the hydromorphic dispersion through cover.
The easternmost Archaean Yamarna Terrane is the least explored terrane under transported cover in the Yilgarn Craton of Western Australia. Our aims are to understand the evolution of the ...paleolandscape, determine the weathering history and depositional processes, and the provenance, mineralogy and geochemistry of the Permian to Quaternary transported cover. This is a necessary step for selecting the appropriate sample media to vector towards buried mineral deposits in this terrane. The Permian cover was deposited in broad, structurally controlled valleys that were carved into and partly to completely truncate the previously weathered Archaean rocks. UPb dating of zircon grains indicates that the main provenance of the Permian cover on the Yamarna Terrane is the Albany-Fraser Orogen, with limited contribution from the Yilgarn Craton, Musgrave Province and Antarctica. The Permian cover of the paleovalleys wedges out laterally towards pre-existing, weathered basement paleohighs, capped by lateritic residuum. The Permian cover is deeply weathered, and consists of upper ferruginous (mottled, brecciated, pisolitic and nodular) and lower kaolinitic, poorly lithified sandstones and mudstones with a basal gravel at the bottom. Above the basal unconformity between the Permian and weathered Archaean, the Rb/Zr ratio decreases sharply and the Permian cover shows negative Eu anomalies (Eu/Eu*) compared to positive Eu/Eu* in the underlying weathered and fresh mafic Archaean rocks, suggesting distal felsic source rocks for the Permian cover. In places, where Au increases, the base of the Permian cover still shows positive Eu/Eu* anomalies, suggesting physical dispersion from proximal mineralized mafic rocks.
The Post-Permian weathering and erosion processes produced an extensive layer of Au-bearing detrital ferruginous clasts derived from lateritic residuum and ferruginous pisoliths and nodules from the Permian cover. These ferruginous grains occur as loose or cemented by Fe oxides forming ferricrete. Ferricrete is not necessarily related to the underlying weathered dolerite compared to the lateritic residuum. This is shown, in some places, by a sharp decrease in the Ti/Zr ratio, high HFSE, negative Eu/Eu*, high LREE/HREE compared to the underlying weathered dolerite suggest an unconformity and physical dispersion from weathered felsic source rocks. The Au-enrichment in the ferricrete derived from the felsic rocks occurred after deposition as a result of hydromorphic dispersion by groundwater. The weathered Permian cover and Archaean rock are covered by aeolian sand within which Au is concentrated in authigenic pisoliths. These pisoliths were formed by periodical water saturation during seasonal water table fluctuation. The unconformities and the ferruginous regolith materials are relevant to Au exploration through cover in the Yamarna Terrane and are highly recommended for regional-scale systematic sampling.
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•The Yamarna Terrane is covered by thick Permian glacial and aeolian sand cover.•The Permian cover deposited between palaeohighs capped by lateritic residuum.•Gold is enriched in lateritic residuum and ferricrete developed within the cover.•Gold is high above the unconformities that are identified by chemical variations.•Age dating showed the Albany Fraser Orogen is the source of the Permian sediments.
Grover on SIMON Anand, Ravi; Maitra, Arpita; Mukhopadhyay, Sourav
Quantum information processing,
2020/9, Letnik:
19, Številka:
9
Journal Article
Recenzirano
Odprti dostop
For any symmetric key cryptosystem with
n
-bit secret key, the key can be recovered in
O
(
2
n
/
2
)
exploiting Grover search algorithm, resulting in the effective key length to be half. In this ...direction, subsequent work has been done on AES and some other block ciphers. On the other hand, lightweight ciphers like
S
I
M
O
N
was left unexplored. In this backdrop, we present Grover’s search algorithm on all the variants of
S
I
M
O
N
and enumerate the quantum resources to implement such attack in terms of NOT, CNOT and Toffoli gates. We also provide the
T
-depth of the circuits and the number of qubits required for the attack. We show that the number of qubits required for implementing Grover on
S
I
M
O
N
2
n
/
m
n
is
O
(
2
n
r
+
m
n
)
, where
r
is the number of chosen plaintext–ciphertext pairs. We run a reduced version of
S
I
M
O
N
in IBMQ quantum simulator and the 14-qubit processor as well. We found that where simulation supports theory, the actual implementation is far from the reality due to the infidelity of the gates and short decoherence time of the qubits. The complete codes for all version of
S
I
M
O
N
have also been presented.
Abstract
Background
The lack of adequate benefit with current 5HT2 / D2 antipsychotics in large proportions of schizophrenic patients suggests it is essential to modulate other mechanisms for ...improving symptoms of schizophrenia (SCZ). Increasing evidence implicates NMDAr hypofunction, and hippocampal hyperactivity, in the dysregulation not only of mesolimbic DA neurons but also of Glu neurons, leading to increasing synaptic activity of Glu in the PFC. Injection of NMDAr antagonists (PCP, ketamine) at doses that produce psychotomimetic effects lead to a downstream increase of Glu neurotransmission at non-NMDAr. The excessive firing and the hyper-glutamatergic tone represent alternative targets of treatment for SCZ ultimately affecting positive, negative, cognitive symptoms. The addition of Glu release inhibitors may augment the benefits of the antipsychotics in patients showing inadequate response.
Evenamide uniquely does not interact with monoaminergic (DA, 5-HT, NA, H) pathways affected by current antipsychotics, or with more than 130 different targets that are involved in CNS activity, except sodium channels. Preclinical data suggests that by the modulation of the firing abnormalities, evenamide normalizes the aberrant spread of Glu excitatory transmission that occurs in the brains of patients with SCZ. Evenamide showed efficacy in animal models relevant to SCZ (sensory motor gating, mania, psychosis, depression, impulse control, cognition, social interaction), in monotherapy and as an add on to first or second generation antipsychotics irrespective of whether impairment was either spontaneous, induced by amphetamine or NMDAr antagonists or stress. Evenamide, has also shown significant benefit in a p.c phase 2 trial as an add-on to risperidone and aripiprazole in patients worsening on dopaminergic/serotoninergic antagonist medication, suggesting it acts through other mechanisms. New animal data further confirm evenamide’s activity in reducing SCZ symptoms provoked by Glu alteration.
Methods
Effects of evenamide (EVE 1.25, 5, 15 mg/kg PO) to restore the impaired information processing (a deficit observed in SCZ), were evaluated in the rat model of the Pre-Pulse Inhibition (PPI) deficit induced by injection of the NMDAr antagonist ketamine (KET 6 mg/kg, SC). Clozapine (CLO 7.5 mg/kg, IP) was used as a positive control.
Results
PPI analysis showed significant main effects for KET to lower PPI levels F(1,264)=139.67, P<0.0001, for EVE F(3,264)=3.14, P<0.05 and CLO to enhance PPI levels F(1,98)=30.89, P<0.001. Notably, significant EVE x KET F(3,264)=2.79, P<0.05 and CLO x KET interactions F(1,98)=5.45, P<0.05 were found.
Post-hoc analyses (Tukey’s) revealed that KET significantly lowered PPI (P<0.0001) for each group; both EVE (5 mg/kg) and CLO significantly increased PPI in KET-treated rats (P=0.02; p<0.001).
Discussion
Evenamide as monotherapy has similar effect to clozapine in reversing ketamine- induced worsening of PPI. Together with previously demonstrated effects to reverse PCP-induced PPI and social interaction deficits, this further supports its potential to affect both positive and negative symptoms of SCZ by targeting altered Glu transmission.
Efficacy of evenamide as an add-on to antipsychotics would revolutionize development of novel antipsychotics that would target aberrant firing and Glu transmission in SCZ. Two clinical trials have been planned to support the hypothesis that the addition of evenamide should add a non-dopaminergic mechanism for augmenting antipsychotic efficacy in patients who are not responding adequately to current antipsychotic, and in patients with treatment resistant SCZ who are not responding/worsening on clozapine.
This article proposes a novel seven-level multilevel inverter (MLI) with integrated output voltage boosting functions. The inverter uses switched capacitors (SCs), a key component of a ...voltage-boosting approach, to achieve the goal of increasing the output voltage at the load end. Additionally, the MLI has the ability to automatically balance the capacitor voltages. The proposed inverter is more cost-effective and has lower conduction losses than those of its rivals since it has fewer components than competing designs. An inductor is used in the capacitor charging loop to both minimize dc source current spikes and enable quicker charging of the capacitor, thereby increasing the capacitor's lifespan. This article provides a number of waveforms, including output voltage and current, under various loading conditions and modulation indices. A laboratory model is also employed to support the viability of the proposed topology. The performance of the system is verified using MATLAB/Simulink. At long last, the maximum achievable experimental efficiency of 98.77% and total harmonic distortion (THD) for output voltage and current were 20.44% and 0.54%, respectively, at 300 V and 1.2 kW load.
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