Effective slip boundary conditions for flows over nanoscale chemical heterogeneities

We study slip boundary conditions for simple fluids at surfaces with nanoscale chemical heterogeneities. Using a perturbative approach, we examine the flow of a Newtonian fluid far from a surface described by a heterogeneous Navier slip boundary condition. In the far-field, we obtain expressions for an effective slip boundary condition in certain limiting cases. These expressions are compared to numerical solutions which show they work well when applied in the appropriate limits. The implications for experimental measurements and for the design of surfaces that exhibit large slip lengths are discussed.Comment: 14 pages, 3 figure

Surface Melting and Breakup of Metal Nanowires: Theory and Molecular Dynamics Simulations

We consider the surface melting of metal nanowires by solving a phenomenological two-parabola Landau model and by conducting molecular dynamics simulations of nickel and aluminium nanowires. The model suggests that surface melting will precede bulk melting when the spreading parameter $\Delta \gamma$ for the melt in contact with the solid surface is positive (i.e. if the melt wets or partially wets the surface) and the wire is sufficiently thick, as is the case for planar surfaces and sufficiently large nanoparticles. Surface melting does not occur if $\Delta \gamma$ is negative. We test this model, which assumes the surface energies of the wire are isotropic, using molecular dynamics simulations. For nickel, we observe the onset of anisotropic surface melting associated with each of the two surface facets present, but this gives way to uniform surface melting and the solid melts radially until the solid core eventually breaks up. For aluminium, while we observe complete surface melting of one facet, the lowest energy surface remains partially dry even up to the point where the melt completely penetrates the solid core.Comment: 11 pages, 13 figures, article submission preprin

Effect of Patterned Slip on Micro and Nanofluidic Flows

We consider the flow of a Newtonian fluid in a nano or microchannel with walls that have patterned variations in slip length. We formulate a set of equations to describe the effects on an incompressible Newtonian flow of small variations in slip, and solve these equations for slow flows. We test these equations using molecular dynamics simulations of flow between two walls which have patterned variations in wettability. Good qualitative agreement and a reasonable degree of quantitative agreement is found between the theory and the molecular dynamics simulations. The results of both analyses show that patterned wettability can be used to induce complex variations in flow. Finally we discuss the implications of our results for the design of microfluidic mixers using slip.Comment: 13 pages, 12 figures, final version for publicatio

Fetal ductus venosus Doppler as a predictor of pregnancy outcome

Background: The ductus venosus (DV) transports oxygenated blood to the developing heart and brain by avoiding the hepatic circulation. Due to the anatomical location of the DV, measurement of DV blood flow velocity waveforms indirectly disclose the cardiac functions and health of the foetus, which represents the pressure gradient between the umbilical vein and right atrium. The aim of this study was to evaluate the value of ductus venosus pulstality index of veins in early pregnancy in prediction of adverse pregnancy outcomes. Methods: 50 pregnant women with a single viable foetus between 13 and 24 weeks participated in this prospective cross-sectional study from 2021 to 2022 at Tanta University Hospital. Results: PI in normal group ranged from 0.80-1.20 with mean value 0.90±0.130 and in abnormal group ranged from 0.46-0.50 with mean value 0.522±0.069. S/a ration in normal group ranged from 1.74-3.18 with mean value 2.30±0.40 and in abnormal group ranged from 1.50-2.05 with mean value 1.833±0.212. There was statistically significant difference between outcomes of pregnancy with ultrasound findings (p<0.05). Conclusions: Numerous foetal disorders that might result in cardiovascular deterioration and other aberrant outcomes in newborns can be managed clinically and predicted perinatally using the DV Doppler examination

“Pengaruh Kualitas Produk, Promosi Dan Saluran Distribusi Terhadap Loyalitas Merek Diukur Melalui Kepuasan Pelanggan “ (Studi Kasus Pada Yamaha Mio Semarang Club)

Brand loyalty became measurement of how much customer possibility will move to other brand. It was the one brand equity element related to profit in the future. Brand loyalty assured customer won\u27t change to competitor\u27s brand, although that brand give cheaper price or better quality. Competition within transportation especially motorcycle, compelled producer created various brand and models to attract customer. Satisfaction and loyalty effort to customer always followed by evaluation to satisfaction level and loyalty reached by costumer. It was needed company management in order to determine marketing strategy which will used in the future properly. This research aimed to found how much influence of product quality, promotion and distribution system to brand distribution measured through customer satisfaction. Population from this research was motorcycle user of Yamaha Mio who joint within Yamaha Mio Semarang Club (YMSC) about 80 persons. This study include within census research, according to Arikunto Suharsini (1996:115) whereas including all of population members as research subject. Measurement scale used scale Likert. Within data analysis used simple linear regression test, double regression test and path analysis by SPSS 16.0 program

The impact of memory effect on space fractional strong quantum couplers with tunable decay behavior and its numerical simulation

The nontrivial behavior of wave packets in the space fractional coupled nonlinear Schrödinger equation has received considerable theoretical attention. The difficulty comes from the fact that the Riesz fractional derivative is inherently a prehistorical operator. In contrast, nonlinear Schrödinger equation with both time and space nonlocal operators, which is the cornerstone in the modeling of a new type of fractional quantum couplers, is still in high demand of attention. This paper is devoted to numerically study the propagation of solitons through a new type of quantum couplers which can be called time-space fractional quantum couplers. The numerical methodology is based on the finite-difference/Galerkin Legendre spectral method with an easy to implement numerical algorithm. The time-fractional derivative is considered to describe the decay behavior and the nonlocal memory of the model. We conduct numerical simulations to observe the performance of the tunable decay and the sharpness behavior of the time-space fractional strongly coupled nonlinear Schrödinger model as well as the performance of the numerical algorithm. Numerical simulations show that the time and space fractional-order operators control the decay behavior or the memory and the sharpness of the interface and undergo a seamless transition of the fractional-order parameters

Rigidly Rotating Strings in Stationary Spacetimes

In this paper we study the motion of a rigidly rotating Nambu-Goto test string in a stationary axisymmetric background spacetime. As special examples we consider the rigid rotation of strings in flat spacetime, where explicit analytic solutions can be obtained, and in the Kerr spacetime where we find an interesting new family of test string solutions. We present a detailed classification of these solutions in the Kerr background.Comment: 19 pages, Latex, 9 figures, revised for publication in Classical and Quantum Gravit

Surface-reconstructed Icosahedral Structures for Lead Clusters

We describe a new family of icosahedral structures for lead clusters. In general, structures in this family contain a Mackay icosahedral core with a reconstructed two-shell outer-layer. This family includes the anti-Mackay icosahedra, which have have a Mackay icosahedral core but with most of the surface atoms in hexagonal close-packed positions. Using a many-body glue potential for lead, we identify two icosahedral structures in this family which have the lowest energies of any known structure in the size range from 900 to 15000 lead atoms. We show that these structures are stabilized by a feature of the many-body glue part of the interatomic potential.Comment: 9 pages, 8 figure

Ipsilateral M1 transcranial direct current stimulation increases excitability of the contralateral M1 during an active motor task: Implications for stroke rehabilitation

IntroductionAnodal transcranial direct current stimulation (a-tDCS) of the primary motor cortex (M1) elicits an increase in cortical excitability that outlasts the period of stimulation. However, little is known about effects of a-tDCS on the contralateral M1 during and after ipsilateral M1 stimulation. Therefore, we investigated the changes in corticospinal excitability and inhibition of the left M1 during and after 20min of a-tDCS to the right M1.Material and methodsEight healthy participants received real (2mA) and SHAM a-tDCS to the right M1 randomized across 2 testing sessions. Single- and paired-pulse transcranial magnetic stimulation (TMS) was applied to the left M1 to measure changes motor-evoked potential (MEP) amplitude from the right extensor carpi radialis (ECR) at 130% of resting and active motor threshold, cortical silent period (CSP) and short-interval cortical inhibition (SICI). Active motor threshold was measured during a wrist extension contraction that was less than 5% of maximal electromyographic activation of the ECR. TMS measurements were recorded at baseline, every 5min for 20min during and 10min after a-tDCS.ResultsThe results showed a significant (P<0.05) increase in left M1 MEP amplitude and reduction in CSP duration during (10 and 15min) and after (immediately and 10min post) a-tDCS to the right M1, only during the active motor task. A significant reduction (P<0.05) in SICI during the active task was also found immediately and 10min post a-tDCS. No significant changes in MEP amplitude, CSP and SICI were observed in the resting or active task during SHAM tDCS.DiscussionThe increase in left M1 MEP amplitude and reduction in CSP and SICI during and after 20min of right M1 a-tDCS is most likely to be attributed to a reduction in interhemispheric inhibition that is modulated by a-tDCS during the performance of an active task. Our findings may have significant implications for stroke rehabilitation whereby the application of a-tDCS on the contralesional M1 during neurorehabilitation of the paretic limb may be beneficial for inducing neuroplasticity of the ipsilesional M1 to improve motor function

Analisis Tingkat Kemacetan Lalu-Lintas dengan Memanfaatkan Citra Satelit Ikonos dan Sistem Informasi Geografis di Ruas Jalan Ahmad Yani, Jalan Slamet Riyadi, dan Jalan Oerip Sumoharjo Kota Surakarta

Penelitian ini dilakukan di Kota Surakarta Provinsi Jawa Tengah dengan tujuan untuk mengetahui kondisi tingkat pelayanan jalan Ahmad Yani, jalan Slamet Riyadi, dan jalan Oerip Sumoharjo serta menganalisis tingkat kemacetan yang terjadi pada ketiga ruas jalan tersebut berdasarkan hasil dari kondisi tingkat pelayanan yang ada pada jalan Ahmad Yani, jalan Slamet Riyadi, dan jalan Oerip Sumoharjo. Metode penelitian yang digunakan dalam penelitian ini adalah metode survei. Sedangkan metode survei yang digunakan adalah metode sampling dimana sampel yang diambil pada saat survei meliputi volume kendaraan, penggunaan lahan, pengukuran luas jalan efektif. Sedangkan persamaan yang digunakan dalam penentuan nilai tingkat pelayanan ruas jalan menggunakan persamaan tingkat pelayanan ruas jalan yang mengacu kepada Manual Kapasitas Jalan Indonesia (MKJI) tahun 1997. Perhitungan dan pengamatan tingkat pelayanan ruas jalan dilakukan pada tiga kali dalam satu hari yaitu pada jam sibuk aktifitas manusia pada jam puncak pagi pukul 07.00 – 09.00, jam puncak siang hari pukul 12.00 – 14.00, dan jam puncak sore hari pada pukul 16.00 – 18.00. Hasil penelitian menunjukan tingkat kemacetan yang terjadi berdasarkan dari hasil pengamatan tingkat pelayanan ruas jalan yang terjadi pada pagi, siang dan sore hari. Tingkat kemacetan jalan yang terjadi pada ruas jalan Ahmad Yani, jalan Slamet Riyadi, dan jalan Oerip Sumoharjo memiliki tiga kelas tingkat kemacetan. Tingkat kemacetan jalan dengan intensitas rendah terjadi pada ruas jalan Ahmad Yani ruas B, ruas jalan dengan intensitas sedang terdapat pada ruas jalan Ahmad Yani ruas A, B dan jalan Slamet Riyadi, sedangkan ruas jalan dengan intensitas kemacetan tinggi berada pada ruas jalan Oerip Sumoharjo