918 research outputs found
Soil fertility, fertilizer, and the maize green revolution in East Africa
This paper investigates the reasons for the low application of external fertilizers on farms in Kenya and Uganda. The analysis uses a large panel of household data with rich soil fertility data at the plot level. The authors control for maize seed selection and household effects by using a fixed-effects semi-parametric endogenous switching model. The results suggest that Kenyan maize farmers have applied inorganic fertilizer at the optimal level, corresponding to the high nitrogen-maize relative price, in one of the two survey years and also responded to the price change over time. In Uganda, even the low application of inorganic fertilizer is not profitable because of its high relative price. The authors conclude that policies that reduce the relative price of fertilizer could be effective in both countries, while the efficacy of policies based on improving farmers'knowledge about fertilizer use will be limited as long as the relative price of fertilizer remains high.Crops&Crop Management Systems,Climate Change and Agriculture,Climate Change Mitigation and Green House Gases,Fertilizers,Food Security
Development of PVE Refrigeration Lubricants for R32
A New-PVE lubricant was developed for use with R32 refrigerant. R32 has been proposed as an alternative refrigerant for R410A refrigerant, to reduce global warming. In this report, we evaluated the relationship between the New-PVE lubricant and R32 and R410A refrigerants. The evaluation items were physical properties (miscibility, solubility, mixture viscosity and volumetric resistivity) and thermal stability and lubricity. In addition, a New-PVE was also developed to improve miscibility with R32 refrigerant
Evaluation of Friction and Wear on PVE Refrigeration Lubricants for HFC Refrigerants
For the prevention of global warming, it is important for home electric appliance to improve the energy saving performance. Air-conditioner is one of home electric appliances, and the improvement of energy consumption efficiency is being performed by various ways. Lubricant for air-conditioner is used to protect sliding surfaces of a compressor. The low friction coefficient lubricant is considered to improve the friction coefficient between rotor and vane of the rotary-type compressor. We evaluated the friction and the wear on PVE refrigeration lubricants for HFC refrigerants. The friction coefficient and wear were measured by using the hermetic type block-on-ring tester. The evaluation items were physical properties (miscibility, solubility, mixture viscosity and volumetric resistivity) and thermal stability
Neutrino-driven massive stellar explosions in 3D fostered by magnetic fields via turbulent -effect
We investigate the influence of magnetic field amplification on the
core-collapse supernovae in highly magnetized progenitors through
three-dimensional simulations. By considering rotating models, we observe a
strong correlation between the exponential growth of the magnetic field in the
gain region and the initiation of shock revival, with a faster onset compared
to the non-rotating model. We highlight that the mean magnetic field
experiences exponential amplification as a result of -effect in the
dynamo process, which works efficiently with the increasing kinetic helicity of
the turbulence within the gain region. Our findings indicate that the
significant amplification of the mean magnetic fields leads to the development
of locally intense turbulent magnetic fields, particularly in the vicinity of
the poles, thereby promoting the revival of the shock by neutrino heating.Comment: 6 pages, 4 figures, submitted to MNRAS Letter
Properties of lubricants for refrigeration system with the low GWP refrigerants
For the prevention of global warming, various low GWP refrigerants (R1234yf, R1234ze, R448A, R449A, R452A, R452B, R454B etc.) were proposed as the alternative to HFC refrigerants for refrigeration system. In this report, the combinations of the low GWP refrigerants and lubricants were evaluated. The evaluation items are physical properties (miscibility, solubility, viscosity, and electric property)and thermal stability
Predominant formation of aromatic aldehyde and acid from a dimeric ÎČ-O-4-type lignin model compound under hydrogen peroxide bleaching conditions with high pH levels
Disk-Driven Rotating Bipolar Outflow in Orion Source I
One of the outstanding problems in star-formation theory concerns the
transfer of angular momentum such that mass can accrete onto a newly born young
stellar object (YSO). From a theoretical standpoint, outflows and jets are
predicted to play an essential role in angular momentum transfer and their
rotation motions have been reported for both low- and high-mass YSOs. However,
little quantitative discussion on outflow launching mechanisms have been
presented for high-mass YSOs due to a lack of observational data. Here we
present a clear signature of rotation in the bipolar outflow driven by Orion
Source I, a high-mass YSO candidate, using the Atacama Large
Millimeter/Submillimeter Array (ALMA). A rotational transition of silicon
monoxide (Si18O) reveals a velocity gradient perpendicular to the outflow axis
which is consistent with that of the circumstellar disk traced by a
high-excitation water (H2O) line. The launching radii and outward velocity of
the outflow are estimated to be >10 au and 10 km s-1, respectively. These
parameters rule out a possibility that the observed outflow is produced by
entrainment of a high-velocity jet, and that contribution from stellar-wind or
X-wind which have smaller launching radii are significant in the case of Source
I. Thus, present results provide a convincing evidence of a rotating outflow
directly driven by the magneto-centrifugal disk wind launched by a high-mass
YSO candidate.Comment: 16 pages, 8 figures. Accepted version of the manuscript before
editing by Nature Astronomy. Published version is available on the SharedIt
link; http://rdcu.be/AfT
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