1,817 research outputs found
Qualitative and quantitative analysis of mixtures of compounds containing both hydrogen and deuterium
Method allows qualitative and quantitative analysis of mixtures of partially deuterated compounds. Nuclear magnetic resonance spectroscopy determines location and amount of deuterium in organic compounds but not fully deuterated compounds. Mass spectroscopy can detect fully deuterated species but not the location
Peramalan Pasang Surut Di Perairan Ujungnegoro Kabupaten Batang Jawa Tengah
Pantai Ujungnegoro memiliki luas kawasan 6.800 Ha.Sebagian besar penduduk di pesisir pantai ujungnegoro yang sebagian besar bermata pencaharian sebagai nelayan. Sebagai wilayah yang terpencil yang dikelilingi oleh laut, dan memiliki potensi wisata bahari yang sangat besar, wilayah ini tidak lepas dari pengaruh parameter oseanografi yaitu pasang surut. Pasang surut merupakan suatu fenomena pergerakan naik turunnya permukaan air laut secara berkala yang diakibatkan oleh kombinasi gaya gravitasi dan gaya tarik benda-benda astronomi terutama oleh bumi, bulan dan matahari. Tujuan dilakukannya penelitian ini adalah untuk meramalkan pasang surut di perairan pantai ujungnegoro karena pasang surut pada tiap perairan berbeda- beda.Analisis harmonik pasang surut menggunakan metode Admiralty. Tujuan perhitungan metode admiralty adalah untuk mendapatkan konstanta harmonik pasang surut yang meliputi Amplitudo, M2, S2, K1, O1, N2, K2, P1, M4, MS4. Hasil dari metode Admiralty diperoleh nilai Formzahl sebesar 1,57 cm maka pasang surut perairan Pantai Ujungnegoro adalah bertipe pasang surut harian tunggal dengan MSL = 64,3 cm, LLWL = 49 cm, dan HHWL = 80 cm.Peramalan Pasang Surut menggunakan software MIKE 21 yang memiliki nilai MRE sebesar 10,761
Analysis of Implementation Methodologies of Deadbeat Direct-Torque and Flux Control (DB-DTFC) for IPMSMs in Stationary and Rotatory Reference Frames
Deadbeat-control is a well-established control technique that uses the inverse machine model to determine the voltage commands required to achieve the desired torque and flux commands. Its classic implementation requires solving a quadratic equation with an extensive number of terms. Moreover, it can be only solved in the dq-reference frame. In this paper, two novel implementations are presented. The first methodology, in the dq-reference frame, reduces the algorithm's complexity and computation time. Moreover, it is immune to estimation errors of the permanent magnet flux. A second methodology based on the flux vector orientation is also presented. As opposed to the classic implementation, the proposed method does not require solving a quadratic equation; this reduces its complexity and computation time. Furthermore, the proposed methodology can be solved both in the dq and aß frames since it relies only on the stator flux's magnitude and angle. Up to date and to the best of the author's knowledge, DB-DTFC in the stationary frame has not been presented before for salient machines. DB-DTFC in the stationary frame reduces the reliance on the position observer and facilitates the implementation of overmodulation techniques and six-step operation. The proposed methodology can operate in the MTPF line without any adjustments and it shows an adequate dynamic performance. Simulation and experimental results validate the methodologies. Caveats regarding their implementation are also discussed
Resolution of diaschisis contributes to early recovery from post-stroke aphasia
Diaschisis is a phenomenon observed in stroke that is defined as neuronal dysfunction in regions spared by the infarction but connected to the lesion site. We combined lesion network mapping and task-based functional MRI in 71 patients with post-stroke aphasia to investigate, whether diaschisis and its resolution contribute to early loss and recovery of language functions. Language activation acquired in the acute, subacute and chronic phase was analyzed in compartments with high and low normative resting-state functional connectivity to the lesion site on an individual basis. Regions with high compared to regions with low lesion connectivity showed a steeper increase in language reactivation from the acute to the subacute phase. This finding is compatible with the assumption of resolution of diaschisis. Additionally, language performance in the subacute phase and improvement from the subacute to the chronic phase significantly correlated with the diaschisis effect and its resolution, respectively, suggesting a behavioral relevance of this effect. We therefore assume that undamaged but functionally connected regions become dysfunctional due to missing input from the lesion contributing to the aphasic deficit. Since these regions are structurally intact, dysfunction resolves over time contributing to the rapid early behavioral improvement observed in aphasic stroke patients. Our results demonstrate that diaschisis and its resolution might be a relevant mechanism of early loss and recovery of language function in acute stroke patients
Modeling magnetospheric fields in the Jupiter system
The various processes which generate magnetic fields within the Jupiter
system are exemplary for a large class of similar processes occurring at other
planets in the solar system, but also around extrasolar planets. Jupiter's
large internal dynamo magnetic field generates a gigantic magnetosphere, which
is strongly rotational driven and possesses large plasma sources located deeply
within the magnetosphere. The combination of the latter two effects is the
primary reason for Jupiter's main auroral ovals. Jupiter's moon Ganymede is the
only known moon with an intrinsic dynamo magnetic field, which generates a
mini-magnetosphere located within Jupiter's larger magnetosphere including two
auroral ovals. Ganymede's magnetosphere is qualitatively different compared to
the one from Jupiter. It possesses no bow shock but develops Alfv\'en wings
similar to most of the extrasolar planets which orbit their host stars within
0.1 AU. New numerical models of Jupiter's and Ganymede's magnetospheres
presented here provide quantitative insight into the processes that maintain
these magnetospheres. Jupiter's magnetospheric field is approximately
time-periodic at the locations of Jupiter's moons and induces secondary
magnetic fields in electrically conductive layers such as subsurface oceans. In
the case of Ganymede, these secondary magnetic fields influence the oscillation
of the location of its auroral ovals. Based on dedicated Hubble Space Telescope
observations, an analysis of the amplitudes of the auroral oscillations
provides evidence that Ganymede harbors a subsurface ocean. Callisto in
contrast does not possess a mini-magnetosphere, but still shows a perturbed
magnetic field environment. Callisto's ionosphere and atmospheric UV emission
is different compared to the other Galilean satellites as it is primarily been
generated by solar photons compared to magnetospheric electrons.Comment: Chapter for Book: Planetary Magnetis
Phonon and Elastic Instabilities in MoC and MoN
We present several results related to the instability of MoC and MoN in the
B1 (sodium chloride) structure. These compounds were proposed as potential
superconductors with moderately high transition temperatures. We show that the
elastic instability in B1-structure MoN, demonstrated several years ago,
persists at elevated pressures, thus offering little hope of stabilizing this
material without chemical doping. For MoC, another material for which
stoichiometric fabrication in the B1-structure has not proven possible, we find
that all of the cubic elastic constants are positive, indicating elastic
stability. Instead, we find X-point phonon instabilities in MoC (and in MoN as
well), further illustrating the rich behavior of carbo-nitride materials. We
also present additional electronic structure results for several transition
metal (Zr, Nb and Mo) carbo-nitride systems and discuss systematic trends in
the properties of these materials. Deviations from strict electron counting
dependencies are apparent.Comment: 5 pages and 4 trailing figures. Submitted to PR
The Postpartum Bonding Questionnaire: Validity evidence from the Brazilian version
The Postpartum Bonding Questionnaire is a self-report questionnaire designed to screen disorders of the mother-infant relationship, which has been adapted to several countries. The aim of this study was to investigate validity evidence of the Brazilian version of the Postpartum Bonding Questionnaire (PBQ-Br) based on its internal structure (dimensionality, reliability, and measurement invariance between mothers with and without depressive symptoms) and on relations to other variables (depression). The present study is part of the Ribeirão Preto and São Luís Brazilian Cohort Studies, encompassing data collected from February 2011 to September 2013. Data were available for 2207 mothers from the general population of Ribeirão Preto and São Luís cities, who were assessed using the PBQ and the Edinburgh Postnatal Depression Scale. Regarding internal structure, the results of confirmatory factor analyses did not support the original four-factor model, nor the alternative structures tested. Exploratory factor analysis suggested a one-factor model with eight items for the collected data, accounting for 38.7% of the total variance with good internal consistency (? = 0.83). Concerning validity evidence based on relations to other variables, the mean PBQ-Br score for mothers with depressive symptoms was significantly higher than for mothers with no depressive symptoms. In conclusion, we found good validity evidence and the PBQ-Br proved to be a useful tool for assessing the mother-infant relationship in the Brazilian general population rather than for its original purpose, i.e., assessing bonding disorders. The results also highlight the importance of developing cross-cultural studies in order to provide useful measures for specific populations.info:eu-repo/semantics/acceptedVersio
Ganymede MHD Model: Magnetospheric Context for Juno's PJ34 Flyby
On June 7th, 2021 the Juno spacecraft visited Ganymede and provided the first
in situ observations since Galileo's last flyby in 2000. The measurements
obtained along a one-dimensional trajectory can be brought into global context
with the help of three-dimensional magnetospheric models. Here we apply the
magnetohydrodynamic model of Duling et al. (2014) to conditions during the Juno
flyby. In addition to the global distribution of plasma variables we provide
mapping of Juno's position along magnetic field lines, Juno's distance from
closed field lines and detailed information about the magnetic field's
topology. We find that Juno did not enter the closed field line region and that
the boundary between open and closed field lines on the surface matches the
poleward edges of the observed auroral ovals. To estimate the sensitivity of
the model results, we carry out a parameter study with different upstream
plasma conditions and other model parameters
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