Capillarity-Driven Flows at the Continuum Limit

We experimentally investigate the dynamics of capillary-driven flows at the nanoscale, using an original platform that combines nanoscale pores and microfluidic features. Our results show a coherent picture across multiple experiments including imbibition, poroelastic transient flows, and a drying-based method that we introduce. In particular, we exploit extreme drying stresses - up to 100 MPa of tension - to drive nanoflows and provide quantitative tests of continuum theories of fluid mechanics and thermodynamics (e.g. Kelvin-Laplace equation) across an unprecedented range. We isolate the breakdown of continuum as a negative slip length of molecular dimension.Comment: 5 pages; 4 figure

Event-Horizon-Telescope Evidence for Alignment of the Black Hole in the Center of the Milky Way with the Inner Stellar Disk

Observations of the black hole in the center of the Milky Way with the Event Horizon Telescope at 1.3 mm have revealed a size of the emitting region that is smaller than the size of the black-hole shadow. This can be reconciled with the spectral properties of the source, if the accretion flow is seen at a relatively high inclination (50-60 degrees). Such an inclination makes the angular momentum of the flow, and perhaps of the black hole, nearly aligned with the angular momenta of the orbits of stars that lie within 3 arcsec from the black hole. We discuss the implications of such an alignment for the properties of the black hole and of its accretion flow. We argue that future Event-Horizon-Telescope observations will not only refine the inclination of Sgr A* but also measure precisely its orientation on the plane of the sky.Comment: To appear in the Astrophysical Journa

Mediating Effect of Dynamic Capabilities on Human Capital as a Driver of Research Productivity of Academic Staff in Kenyan Universities

Research productivity is increasingly being recognised as a key measure of achievement and is therefore a basis for promotion and tenure for academic staff as well as an important component in the global ranking of universities. However, research productivity of academic staff in Kenyan universities is characterised by limited publications, resulting in the low positioning of Kenyan universities in global rankings. The purpose of this study was to investigate the influence of human capital and dynamic capabilities on research productivity of academic staff in Kenyan universities. This study adopted a correlational research design and sampled 392 academic staff members. Both regression and bootstrap analyses were used to test the hypotheses. The findings revealed that human capital has a significant influence on research productivity of academic staff in Kenyan universities; however, the influence of human capital is not direct, but is partially mediated by dynamic capabilities. The outcomes of the study provide insight to academic staff to invest heavily in both human capital and dynamic capabilities to foster research productivity. Additionally, the results of the study provide an understanding to the university management on possible strategic choices that can boost the research productivity of academic staff

Initial Data Identication in Space Dependent Conservation Laws and Hamilton-Jacobi Equations

Consider a Conservation Law and a Hamilton-Jacobi equation with a ux/Hamiltonian depending also on the space variable. We characterize rst the attainable set of the two equations and, second, the set of initial data evolving at a prescribed time into a prescribed prole. An explicit example then shows the deep dierences between the cases of x-independent and x-dependent uxes/Hamiltonians

AKTIVITAS KOMUNIKASI PEMASARAN PADA MEDIA SOSIAL INSTAGRAM COSAN DALAM MEMBENTUK BRAND IMAGE

Teknologi yang berkembang pesat, dapat memudahkan bagi mereka yang mau belajar maupun menyusahkan bagi mereka yang malas akan kemajuan. Di era digital ini, produk tidak hanya disebarluaskan menggunakan metode penjualan langsung saja, melainkan dapat menggunakan metode pemasaran melalui internet, khususnya media sosial Instagram. Memaksimalkan kegiatan atau aktivitas komunikasi pemasaran merupakan jalan yang dilakukan untuk mencapai hal tersebut. Kegiatan komunikasi pemasaran tersebut meliputi: Advertising, Direct Marketing, Sales Promotion, Internet Marketing, Personal Selling dan Public Relation. Pada penelitian ini, peneliti berfokus pada aktivitas komunikasi pemasaran pada media sosial Instagram Cosan dalam membentuk brand image mereka. Pendekatan yang digunakan dalam penelitian ini adalah deskriptif kualitatif dengan wawancara dan studi dokumen sebagai pengumpulan data. Terdapat 3 (tiga) narasumber dalam penelitian ini yang merupakan pemilik usaha sekaligus Marketing Manager dan Manajer Operasional Cosan, serta seorang konsumen Cosan. Ketiga narasumber berperan penting dalam setiap kegiatan aktivitas komunikasi pemasaran Cosan, khususnya pada media sosial Instagram. Hasil penelitian ini menunjukkan bahwa Cosan dalam aktivitas komunikasi pemasarannya menggunakan media sosial. Penggunaan media sosial ini masuk dalam salah satu kategori bauran pemasaran promosi yang masuk dalam internet marketing, bagian dari aktivitas komunikasi pemasaran. Internet marketing yaitu mengenai bagaimana perusahaan Cosan memanfaatkan internet (media sosial) untuk melakukan aktivitas komunikasi pemasaran

Monitoring of a Large Cracked Concrete Sample with Non-Linear Mixing of Ultrasonic Coda Waves

International audienceA high precision can be achieved with ultrasonic coda waves to monitor the mechanical properties of concrete material (~10-5 in relative). This high sensitivity can be used to detect damage initiation and to closely follow concrete mechanical properties evolution with time. This advantage is counterbalance by the influence of environmental conditions making reproducibility of any experiment in concrete a challenging issue especially when in situ measurements are performed. Indeed thermal and water gradients present in the thickness of the structures (several decimetres) cannot be controlled and must be compensated. In this paper a protocol to remove environmental bias is proposed. Furthermore, to follow the apparition of a tensile crack in a metric size structure, non-linear mixing of coda wave via frequency-swept pump waves is tested. It is shown that, when the crack is closed (by pre-stressing cables), it is still possible to detect its presence. The non-linearity of the cracked zone remains at a high level, comparable to the case when the crack was open

Direct Interactions in Relativistic Statistical Mechanics

Directly interacting particles are considered in the multitime formalism of predictive relativistic mechanics. When the equations of motion leave a phase-space volume invariant, it turns out that the phase average of any first integral, covariantly defined as a flux across a $7n$-dimensional surface, is conserved. The Hamiltonian case is discussed, a class of simple models is exhibited, and a tentative definition of equilibrium is proposed.Comment: Plain Tex file, 26 page