2,278 research outputs found
Analytical continuum mechanics \`a la Hamilton-Piola: least action principle for second gradient continua and capillary fluids
In this paper a stationary action principle is proven to hold for capillary
fluids, i.e. fluids for which the deformation energy has the form suggested,
starting from molecular arguments, for instance by Cahn and Hilliard. Remark
that these fluids are sometimes also called Korteweg-de Vries or Cahn-Allen. In
general continua whose deformation energy depend on the second gradient of
placement are called second gradient (or Piola-Toupin or Mindlin or
Green-Rivlin or Germain or second gradient) continua. In the present paper, a
material description for second gradient continua is formulated. A Lagrangian
action is introduced in both material and spatial description and the
corresponding Euler-Lagrange bulk and boundary conditions are found. These
conditions are formulated in terms of an objective deformation energy volume
density in two cases: when this energy is assumed to depend on either C and
grad C or on C^-1 and grad C^-1 ; where C is the Cauchy-Green deformation
tensor. When particularized to energies which characterize fluid materials, the
capillary fluid evolution conditions (see e.g. Casal or Seppecher for an
alternative deduction based on thermodynamic arguments) are recovered. A
version of Bernoulli law valid for capillary fluids is found and, in the
Appendix B, useful kinematic formulas for the present variational formulation
are proposed. Historical comments about Gabrio Piola's contribution to
continuum analytical mechanics are also presented. In this context the reader
is also referred to Capecchi and Ruta.Comment: 52 page
ANALISIS STRUKTUR FISIK PUISI “KANGEN†KARYA W. S RENDRA
Literary work is the representative or outpouring of the heart of an author, can be poured in the form of oral and written. Poetry is the disclosure of ideas, ideas, or feelings of the heart using figurative language. Writing poetry is usually used to criticize or express an event. In poetry there is a physical structure and an inner structure. The author chose the poem by W. S Rendra entitled "Kangen" to be a research, it intends to know the physical structure of the poem. Both in terms of diction, Imaji, concrete words, figurative language, rhyme, and face. This research uses descriptive method, aims to make the description systematically, factually, and accurately about the physical structure of poetry. The physical structure of W.S Rendra's heartache is very different from the writing of poetry in general, W. S Rendra packs his poems freely with figurative words and diction choices that come out of the romantic path
Measurement of the Gravity-Field Curvature by Atom Interferometry
We present the first direct measurement of the gravity-field curvature based
on three conjugated atom interferometers. Three atomic clouds launched in the
vertical direction are simultaneously interrogated by the same atom
interferometry sequence and used to probe the gravity field at three equally
spaced positions. The vertical component of the gravity-field curvature
generated by nearby source masses is measured from the difference between
adjacent gravity gradient values. Curvature measurements are of interest in
geodesy studies and for the validation of gravitational models of the
surrounding environment. The possibility of using such a scheme for a new
determination of the Newtonian constant of gravity is also discussed.Comment: 5 pages, 3 figure
Quantum test of the equivalence principle for atoms in superpositions of internal energy eigenstates
The Einstein Equivalence Principle (EEP) has a central role in the
understanding of gravity and space-time. In its weak form, or Weak Equivalence
Principle (WEP), it directly implies equivalence between inertial and
gravitational mass. Verifying this principle in a regime where the relevant
properties of the test body must be described by quantum theory has profound
implications. Here we report on a novel WEP test for atoms. A Bragg atom
interferometer in a gravity gradiometer configuration compares the free fall of
rubidium atoms prepared in two hyperfine states and in their coherent
superposition. The use of the superposition state allows testing genuine
quantum aspects of EEP with no classical analogue, which have remained
completely unexplored so far. In addition, we measure the Eotvos ratio of atoms
in two hyperfine levels with relative uncertainty in the low ,
improving previous results by almost two orders of magnitude.Comment: Accepted for publication in Nature Communicatio
Sensitivity limits of a Raman atom interferometer as a gravity gradiometer
We evaluate the sensitivity of a dual cloud atom interferometer to the
measurement of vertical gravity gradient. We study the influence of most
relevant experimental parameters on noise and long-term drifts. Results are
also applied to the case of doubly differential measurements of the
gravitational signal from local source masses. We achieve a short term
sensitivity of 3*10^(-9) g/Hz^(-1/2) to differential gravity acceleration,
limited by the quantum projection noise of the instrument. Active control of
the most critical parameters allows to reach a resolution of 5*10^(-11) g after
8000 s on the measurement of differential gravity acceleration. The long term
stability is compatible with a measurement of the gravitational constant G at
the level of 10^(-4) after an integration time of about 100 hours.Comment: 19 pages, 20 figure
Distribución y relaciones sistemáticas entre poblaciones del género Ctenomys (Rodentia, Ctenomydae) de la provincia de Mendoza (Argentina)
Adherence to the mediterranean diet in association with self-perception of diet sustainability, anthropometric and sociodemographic factors: A cross-sectional study in italian adults
The adoption of sustainable dietary models, such as the Mediterranean Diet (MD), can be a valuable strategy to preserve ecosystems and human health. This study aims to investigate in an Italian adult representative sample the adherence to the MD and to what extent it is associated with the self-perceived adoption of a sustainable diet, the consideration of the MD as a sustainable dietary model, and anthropometric and sociodemographic factors. By applying an online survey (n = 838, 18–65 years, 52% female), an intermediate level of MD adherence (median: 4.0, IR: 3.0–4.0) in a 0–9 range was observed. Only 50% of the total sample confirmed the MD as a sustainable dietary model, and 84% declared no or low perception of adopting a sustainable diet. Being female, having a higher income and education level, considering the MD as a sustainable dietary model, as well as the perception of having a sustainable diet were the most relevant factors influencing the probability of having a high score (≥6) of adherence to the MD. This study suggests a gradual shift away from the MD in Italy and supports the need to address efforts for developing intervention strategies tailored to adults for improving diet quality. Furthermore, a public campaign should stress the link between a diet and its environmental impact to foster nutritionally adequate and eco-friendly dietary behaviors
The functional milk
Introduction - In addition to providing all the essential nutrients for the neonate, milk is also a vector of a wide range of immune effector molecules. It has been recently observed that milk IgA can be successfully used for prophylactic or therapeutic treatment against infections by Candida albicans and Helicobacter pylori, which represent serious risk for the health of the digestive system. IgA is the major immunoglobulin present in human milk, but it is 4-5 times less abundant in bovine milk. Since bovine milk is the most consumed milk worldwide, the detection of factors affecting the level of IgA in bovine milk offers great potential to add value to the dairy products.
Aim - The present study aimed at evaluating the effect of day in milk and parity on IgA level in colostrum and milk of dairy cows.
Materials and methods - Seven primiparous and 7 multiparous healthy Fresian cows were studied for 3 months after calving. All the cows were fed the same experimental diet, over the study period. On day 0, 1, 3, 7, 30, 60 and 90 of lactation, milk yield was recorded, colostrum and milk samples were taken. Colostrum and milk samples were obtained mixing morning and evening milkings and then tested for protein, fat, lactose, casein and urea content, somatic cell count and total bacterial count (TBC). Skimmed colostrum and milk were tested for IgA by ELISA. Data were evaluated by ANOVA.
Results - Maximum milk production was observed on day 30 for multiparous cows (43.3 L/d) and on day 60 for the primiparous ones (40.5 L/d). In both groups, the highest levels of IgA were found at calving. The day after, colostrum IgA concentration dramatically decreased, remaining at low levels for the rest of the study period. On calving, IgA level was higher in the colostrum from multiparous than primiparous cows (782 vs. 640 \ub5g/ml; P<0.01). On day 0, 60 and 90, TBC was higher in milk from multiparous than primiparous cows (P=0.06). Between 7 and 90 days of lactation, TBC was negatively correlated whether with milk IgA levels (r = -0.506, P<0.01; r = -0.396, P<0.05 for multiparous and primiparous cows, respectively) and with milk IgA daily yield (r = -0.504, P<0.01; r = -0.501, P<0.01).
Conclusions - This research gives a description of the pattern of IgA in colustrum and milk of dairy cows, during the first months of lactation, providing valuable information to maximize the positive effects of milk consumption on consumer health
Penerapan Teknik Blind Source Separation Untuk Memisahkan Noise Dari Sinyal Akustik Yang Non Gaussian
Pada sistem komunikasi bawah air, seringkali sinyal yang diterima oleh sensor berasal dari hasil pencampuran sumber sinyal dengan sinyal-sinyal akustik lain di lingkungan bawah air. Hal ini menjadikan sinyal yang didapatkan menjadi tidak sesuai dengan yang diinginkan. Teknik Blind Source Separation (BSS) dipakai di sini untuk memisahkan sinyal-sinyal yang bercampur tersebut. Dalam tugas akhir ini, dilakukan pemisahan sinyal akustik dengan menggunakan Natural Gradient ICA berdasarkan Generalized Gaussian Model yang didapat dari karakteristik distribusi sumber sinyal akustik non-gaussian yakni ship radiated noise dan sea ambient noise. Pemisahan sinyal akustik dilakukan sebanyak tiga kali yakni dengan simulasi, toolbox ICALABS V3, dan menggunakan pemisahan sinyal akustik dari data riil pengukuran. Dari hasil simulasi menunjukkan pemisahan dengan algoritma Natural Gradien ICA berdasarkan Generalized Gaussian Model berjalan dengan baik. Hal ini ditunjukkan dengan nilai SIR shrimp.wav = 48.9946 dB dan ferry.wav = 46.9309. dB. Sedangkan rata-rata MSE shrimp.wav = 1.2605 x 10-5 dan ferry.wav = 2.0272 x 10 -5
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