579 research outputs found
An Experimental Investigation of the Shergottite NWA 6162
The Martian meteorite North West Africa 6162 (NWA 6162) is a shergottite found in Morocco in 2010. The meteorite has large olivine crystals with Mg-depleted rims as low as FO(sub 65) and Mg-rich cores of up to FO(sub 74). It is similar both in appearance and composition to another shergottite, SaU 005. Our objective is to determine if NWA 6162 represents a liquid or if it is a product of olivine accumulation. Olivine accumulation would leave the parent melt Mg-depleted and the complementary olivine cumulates would be Mg-enriched. Therefore, if NWA 6162 is a partial cumulate we would expect that liquidus olivines grown from this bulk composition would be more magnesium than olivines in the natural sample
Effect of Fluorine on Near-Liquidus Phase Equilibria of Basalts
Volatile species such as H2O, CO2, F, and Cl have significant impact in generation and differentiation of basaltic melts. Thus far experimental work has primarily focused on the effect of water and carbon dioxide on basalt crystallization, liquid-line of descent, and mantle melting [e.g., 1, 2] and the effects of halogens have received far less attention [3-4]. However, melts in the planetary interiors can have non-negligible chlorine and fluorine concentrations. Here, we explore the effects of fluorine on near-liquidus phase equilibria of basalt. We have conducted nominally anhydrous piston cylinder experiments using graphite capsules at 0.6 - 1.5 GPa on an Fe-rich model basalt composition. 1.75 wt% fluorine was added to the starting mix in the form of AgF2. Fluorine in the experimental glass was measured by SIMS and major elements of glass and minerals were analyzed by EPMA. Nominally volatile free experiments yield a liquidus temperature from 1330 C at 0.8GPa to 1400 at 1.6GPa and an olivine(Fo72)-pyroxene(En68)-liquid multiple saturation point at 1.25 GPa and 1375 C. The F-bearing experiments yield a liquiudus temperature from 1260 C at 0.6GPa to 1305 at 1.5GPa and an ol(Fo66)-pyx(En64)-MSP at 1 GPa and 1260 C. This shows that F depresses the basalt liquidus, extends the pyroxene stability field to lower pressure, and forces the liquidus phases to be more Fe-rich. KD(Fe-Mg/mineral-melt) calculated for both pyroxenes and olivines show an increase with increasing F content of the melt. Therefore, we infer that F complexes with Mg in the melt and thus increases the melt s silica activity, depressing the liquidus and changing the composition of the crystallizing minerals. Our study demonstrates that on a weight percent basis, the effect of fluorine is similar to the effect of H2O [1] and Cl [3] on freezing point depression of basalts. But on an atomic fraction basis, the effect of F on liquidus depression of basalts is xxxx compared to the effect of H. Future studies on kimberlitic and subduction zone magmas, which could have significant amount of fluorine, will need to consider the combined effects of F, Cl, and H on their stability and chemical evolution
Carbon Border Adjustment Mechanism Impact Assessment Report for Vietnam
The EUâs Carbon Border Adjustment Mechanism (CBAM) is evolving rapidly, with many uncertainties remaining regarding its long-term scope, embedded emissions calculation, and reactions of EU-trade partners. In its current form, the CBAM can affect Vietnamese enterprises exporting to EU although its direct impacts on Vietnamâs GDP are unlikely significant. If the CBAM is expanded to other trade-intensive sectors of Vietnam or taken up by other key trading partners of Vietnam, the impacts may grow quickly. Therefore, Vietnam should engage proactively with the CBAM and prepare for mitigation of potential impacts. One of the pro-active approaches is to accelerate and deepen the adoption of carbon pricing. This will facilitate energy transition, support achievement of Vietnamâs climate change mitigation target (NDC) under the Paris Agreement and long-term net-zero targets and would allow to harness co-benefits. It is also advisable for Vietnam to engage in constructive dialogues with the EU in order to negotiate a fair implementation of CBAM that takes into account Vietnamâs efforts. A key demand here should be the use of emissions credits instead of having to buy CBAM certificates
Dengue epidemic in southern Vietnam, 1998.
A widespread epidemic of dengue hemorrhagic fever (DHF) occurred in southern Vietnam in 1998, with 438.98 cases/100,000 population and 342 deaths. The number of DHF cases and deaths per 100,000 population increased 152.4% and 151.8%, respectively, over a 1997 epidemic. Dengue viruses were isolated from 143 patient blood samples; DEN-3 virus was identified as the predominant serotype, although a resurgence of DEN-4 was noted
Efficient Security and Authentication for Edge-Based Internet of Medical Things
Internet of Medical Things (IoMT)-driven smart health and emotional care is revolutionizing the healthcare industry by embracing several technologies related to multimodal physiological data collection, communication, intelligent automation, and efficient manufacturing. The authentication and secure exchange of electronic health records (EHRs), comprising of patient data collected using wearable sensors and laboratory investigations, is of paramount importance. In this article, we present a novel high payload and reversible EHR embedding framework to secure the patient information successfully and authenticate the received content. The proposed approach is based on novel left data mapping (LDM), pixel repetition method (PRM), RC4 encryption, and checksum computation. The input image of size is upscaled by using PRM that guarantees reversibility with lesser computational complexity. The binary secret data are encrypted using the RC4 encryption algorithm and then the encrypted data are grouped into 3-bit chunks and converted into decimal equivalents. Before embedding, these decimal digits are encoded by LDM. To embed the shifted data, the cover image is divided into blocks and then in each block, two digits are embedded into the counter diagonal pixels. For tamper detection and localization, a checksum digit computed from the block is embedded into one of the main diagonal pixels. A fragile logo is embedded into the cover images in addition to EHR to facilitate early tamper detection. The average peak signal to noise ratio (PSNR) of the stego-images obtained is 41.95 dB for a very high embedding capacity of 2.25 bits per pixel. Furthermore, the embedding time is less than 0.2 s. Experimental results reveal that our approach outperforms many state-of-the-art techniques in terms of payload, imperceptibility, computational complexity, and capability to detect and localize tamper. All the attributes affirm that the proposed scheme is a potential candidate for providing better security and authentication solutions for IoMT-based smart health
Driving and Deterrent Factors Affecting Organic Food Consumption in Vietnam
This study aims to determine driving factors significantly influencing the purchase intention and to identify impediments creating the intention âbehavior gap regarding organic food consumption in Vietnam. The chosen driving factors affecting the organic food purchase intention in this study are health benefits, environmental awareness, and social norms, whereas trust, price, and convenience as well as availability are investigated as deterrent factors of the link between intention and behavior. A structured online questionnaire with snow-balling sampling method was distributed to collect a representative sample of 466 Vietnamese consumers nationwide. A five-point likert scale was used for the level of approval for 36 statements. Statistical tools of SPSS 22.0 including descriptive analysis, principal component analysis, and multiple regression analysis models were used for data analysis. The results showed that health benefits, environmental awareness, and social norms were facilitators of organic food purchase intention. Although high intention to purchase organic foods was identified in Vietnam, it was not translated into actual purchase behavior. The main barriers for the inconsistency were premium price and low availability of organic products or inconvenience to buy in the market. Lack of trust insignificantly impacted on organic food choices among Vietnamese consumers in this study. These empirical findings and suggestions are beneficial for all players across supply chains
Effectiveness of natural coagulant in coagulation process: A review
Natural coagulants have been increasingly popular in the past few years due to its benefits and the fact that it resolves mos t of the associated problems when using chemical coagulants. Plant-based natural coagulants perform coagulation either by polymer bridging or charge neutralization, it can be extracted from various plant components. Concerted research and development efforts have been conducted in discovering new plant species and constituents that can be used as natural coagulants, which further boosting the effectiveness of existing plant-based natural coagulants. The objective of this paper is to provide a mini review on studies done over the span of ten years regarding plant-based natural coagulants. This paper also includes advantages and disadvantages of natural coagulants prior to identify sever al potential research gaps to provide platform towards the need of further study
Lowest-lying Tetra-Quark Hadrons in Anisotropic Lattice QCD
We present a detailed study of lowest-lying hadrons in
quenched improved anisotropic lattice QCD. Using the and
diquark-antidiquark local and smeared operators, we attempt to isolate the
signal for and states in two flavour
QCD. In the chiral limit of light-quark mass region, the lowest scalar
state is found to have a mass, MeV, which is slightly
lower than the experimentally observed . The results from our
variational analysis do not indicate a signature of a tetraquark resonance in
I=1 and I=2 channels. After the chiral extrapolation the lowest
state is found to have a mass, MeV. We analysed the
static potential extracted form a tetraquark Wilson loop and illustrated
the behaviour of the state as a bound state, unbinding at some critical
diquark separation. From our analysis we conclude that scalar system
appears as a two-pion scattering state and that there is no spatially-localised
state in the light-quark mass region.Comment: 9 pages, 10 figure
Hamiltonian Study of Improved Lattice Gauge Theory in Three Dimensions
A comprehensive analysis of the Symanzik improved anisotropic
three-dimensional U(1) lattice gauge theory in the Hamiltonian limit is made.
Monte Carlo techniques are used to obtain numerical results for the static
potential, ratio of the renormalized and bare anisotropies, the string tension,
lowest glueball masses and the mass ratio. Evidence that rotational symmetry is
established more accurately for the Symanzik improved anisotropic action is
presented. The discretization errors in the static potential and the
renormalization of the bare anisotropy are found to be only a few percent
compared to errors of about 20-25% for the unimproved gauge action. Evidence of
scaling in the string tension, antisymmetric mass gap and the mass ratio is
observed in the weak coupling region and the behaviour is tested against
analytic and numerical results obtained in various other Hamiltonian studies of
the theory. We find that more accurate determination of the scaling
coefficients of the string tension and the antisymmetric mass gap has been
achieved, and the agreement with various other Hamiltonian studies of the
theory is excellent. The improved action is found to give faster convergence to
the continuum limit. Very clear evidence is obtained that in the continuum
limit the glueball ratio approaches exactly 2, as expected in a
theory of free, massive bosons.Comment: 13 pages, 15 figures, submitted to Phys. Rev.
Foot Bone in Vivo: Its Center of Mass and Centroid of Shape
This paper studies foot bone geometrical shape and its mass distribution and
establishes an assessment method of bone strength. Using spiral CT scanning,
with an accuracy of sub-millimeter, we analyze the data of 384 pieces of foot
bones in vivo and investigate the relationship between the bone's external
shape and internal structure. This analysis is explored on the bases of the
bone's center of mass and its centroid of shape. We observe the phenomenon of
superposition of center of mass and centroid of shape fairly precisely,
indicating a possible appearance of biomechanical organism. We investigate two
aspects of the geometrical shape, (i) distance between compact bone's centroid
of shape and that of the bone and (ii) the mean radius of the same density bone
issue relative to the bone's centroid of shape. These quantities are used to
interpret the influence of different physical exercises imposed on bone
strength, thereby contributing to an alternate assessment technique to bone
strength.Comment: 9 pages, 4 figure
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