1,009 research outputs found
Personal Papers (MS 80-0002)
No full textLetter from Harris L. Kempner to Edward A. Janus requesting a reservation at the Statler Hotel for the 25th
Oral History Interview: Graf, Truman (1071)
No full textAbstract: In his 2009 interview with Edward Janus, Truman Graf traced his childhood on a Wisconsin dairy farm and his long career in the state?s dairy industry. He described obstacles facing his father and other farmers in the 1920s and through the Great Depression, while also detailing New Deal relief programs. Graf related his personal background to his career at UW-Madison and beyond, focusing primarily on cooperatives, milk pricing, and milk promotion. This interview was conducted for inclusion into the UW-Madison Oral History Program.
Keywords: agriculture; dairy farming; Manitowoc County; cows; Carnation; the Depression; cooperatives; Lake to Lake cooperative; Federal Land Grant Program; the New Deal; World War II; threshing; Negro league baseball; progressive farming; conservation; radio; Art Murphy; Federal Milk Order Program; milk orders; Battle of Cemetery Hill; UW-Madison College of Agriculture; National Farmers Organization (NFO); Rudy Froker; Cliff Hardin; Truman Torgerson; George Ruppel; Babcock test; supply and demand; Lyman McKee; Navy Air Corps; whey
Personal Papers (MS 80-0002)
No full textLetter from Edward A. Janus to Harris L. Kempner apologizing that their room will not be ready by 9 a.m
Letter from P. Edwd. Connor to Janus W. Segfield, 1854
No full textArrived 8 days from San Francisco. Met Beale at Los Angeles on his way to Colorado. Reports seeing no less than twenty five hundred acres of land sowed with wheat with six miles of irrigation. Estimates twenty five hundred Indians on the reservation. Produce cultivated, Corn, barley, wheat, potatoes, tropical fruits adapted to North American climate like Oranges, peaches, apples, apricots, pears, pomegranates. Compliments Beale's plan for the tribes. Predicts there will be enough crops to supply the Indians south of the Sacramento River
Simulation of diffusiophoresis force and the confinement effect of Janus particles with the continuum method
No full textThe Janus particle is a special class of colloidal particle that has different surface characteristics on its two hemispheres. In the microsystem field, an interesting application is the Janus particle's self-propulsion. Diffusiophoresis (DFP) provides one possible mechanism to explain this phenomenon. In this paper, we used the continuum model to simulate DFP and to study the confinement effect of Janus particles travelling on the substrate. In the experiment, we noticed a special quasi-1D motion, in which the DFP force is dominant and particles move at a constant velocity within a short interval approximately along a straight line. This enables us to adopt a reference frame to numerically study the distributions of the flow field and concentration field and hence to evaluate the different forces. Because the confinement effect has a great influence on the magnitude of forces, the gaps were calculated accurately according to the force balance principle. Meanwhile, the fitting coefficients to match the experimental and numerical results were suggested. This result may help us to get a better understanding of self-propulsion and is also beneficial for designing a DFP-based micro-device. (C) 2014 Author(s)
Synthesis and Use of Janus SiO2 Nanoparticles for Formulating Model Heavy Oil Macroemulsions
No full textJanus
nanoparticles have applications in many fields. Particularly, the oil industry
is interested in applying them for enhanced oil recovery. Within this context,
there is a need to understand the influence of the factors involved in the
formulation of crude oil type emulsions over their properties and rheological
behavior. In this contribution, spherical SiO2 Janus nanoparticles
of two different sizes were synthesized and used as surfactants for the
formulation of aqueous emulsions with two model oils: namely, squalane and
vacuum gas oil. Factorial experiments were designed and made to analyze the
effects of the particle size of the Janus nanoparticles, the water content, the
emulsification energy, and of the second and third order interactions between
these variables over the droplet size distributions, polydispersity, and
rheological profiles of the emulsions. On the one hand, it was found that the
used Janus nanoparticles produced either water in oil (for vacuum gas oil) or
oil in water (for squalane) depending on
the chemistry of the oil phase. On the other hand, it was demonstrated that
non-additive factors play an important role over the properties of the
emulsions; especially in the case of the water in oil ones. These effects also
implied non-additive correlations between the droplet size distributions of the
emulsions and their rheological behavior. Therefore, this work demonstrates
that simpler linear relationships do not suffice for finding the best
conditions for formulating crude oil type emulsions aimed for applications such
as enhanced oil recovery.</p
Janus particle microshuttle: 1D directional self-propulsion modulated by AC electrical field
No full textA catalytic Janus particle is capable of gaining energy from the surrounding fuel solution to drive itself to move continuously, which has an important impact in different fields, especially the field of micro-systems. However, the randomness of self-propulsion at the microscale restricts its use in practice. Achieving a directed self-propelled movement would greatly promote the application of the Janus particle. We proved experimentally that an AC electric field was an effective way to suppress Brownian motion and control the direction of self-propelled movement. The self-propulsion and dielectrophoretic response of a 2μm Janus particle were observed and the related basic data were collected. Interdigital electrodes, 20 μm in width, were energized in pulsed style to modulate the self-propulsion, which resulted in a shuttle-style motion in which a single Janus particle moved to and fro inside the strip electrode. The change of direction depends on its unique position: the catalyst side is always pointed outward and the orientation angle relative to the electrode is about 60°. Numerical simulation also proved that this position is reasonable. The present study could be beneficial with regard to self-propulsion and AC electrokinetics of the Janus particle
Hollow Janus cylinders at liquid interfaces
No full textIn this dissertation, capillary-induced interactions and self-assembly behavior of amphiphilic hollow Janus cylinders at an air-water interface is numerically investigated. First, preferred orientation of a single hollow Janus cylinder is determined as a function of amphiphilicity and aspect ratio. When the cylinder is horizontal (long axis parallel to the interface), the shape of the deformed interface and the resulting capillary-induced interactions between a pair of cylinders is examined. In addition, preferred tip-to-tip or side-by-side assembly behavior of a pair of cylinders is determined by minimizing the total interfacial energy of the system. The preferred assembly behavior of a pair of hollow Janus cylinders is side-by-side for higher amphiphilicities, but as the amphiphilicity is reduced, tip-to-tip orientation becomes similarly preferable. The case of hollow Janus cylinders is also compared with their homogeneous counterparts as well as with solid homogeneous and solid Janus cylinders. The significant difference between Janus and homogeneous hollow cylinders is that the preferred orientation of a homogeneous hollow cylinder is horizontal with respect to the interface for given contact angles and at large aspect ratios. Meanwhile hollow Janus cylinders with large aspect ratios and amphiphilicities (beta≥ 20) prefer a vertical orientation (piercing the interface). The preferred orientation of a single solid Janus cylinder behaves similarly to its hollow counterpart except it prefers a vertical orientation at higher amphiphilicities. In comparison, single hollow and solid homogeneous cylinders have almost similar preferred orientation. The outcome of this study may provide insight on self-assembly behavior of model hollow particles, such as carbon nanotubes, at liquid interfaces for fabrication of functional monolayers or for use as interface stabilizers in foam and emulsions.M.S.Includes bibliographical referencesby Robert Wei
Note on generalized Janus configurations
No full textWe study several aspects of generalized Janus configuration, which includes a theta term. We investigate the vacuum structure of the theory and find that unlike the Janus configuration without theta term there is no nontrivial vacuum. We also discuss BPS soliton configuration both by supersymmetry analysis and from energy functional. The half BPS configurations could be realized by introducing transverse (p,q)-strings in original brane configuration corresponding to generalized Janus configuration. It turns out the BPS soliton could be taken as modified dyon. We discuss the solution of half BPS equations for the sharp interface case. Moreover we construct less supersymmetric Janus configuration with theta term.Physics, Particles & FieldsSCI(E)2ARTICLE2nul
Orientation of Spherical Janus Nanoparticles: Force and Torque Calculations due to an External Electric Field
No full textJanus particles are colloidal particles for which one half of the surface has different attributes than the other half. One property of a spherical dielectric particle with half of its surface covered by a layer of another dielectric or metal is that it has a non-uniform scattering pattern when exposed to light. However, the angle with which the light is shone on the particle has a large effect on the scattering pattern produced. Thus it is important that we are able to orient these Janus particles. The orientation can be controlled if we apply an electric field to the particle for example. The movement of colloidal particles with an electric field is widely studied and this field is called dielectrophoresis. For a Janus particle, the calculations for the force and torque become complicated. The movement and rotation of these particles have been studied, however, no analytic solution has been found. In this report, we derive a semi-analytic description of the force and torque due to an external electric field on a spherical Janus particle. For this, first the potential due to an external electric field is determined and then the force and torque are calculated with two methods: the dipole approximation and the Maxwell Stress Tensor method. In the dipole approximation, there is no force on the Janus particle. But, there is a torque on the particle in the dipole approximation. Due to this torque, the Janus particle will orient itself such that its cap points in the direction perpendicular to the applied field. For the torque calculated with the Maxwell Stress Tensor, we get a similar result as in the dipole approximation. On the other hand, according to the calculations with the stress tensor, there is a relatively small force on the particle.Applied Mathematics | Applied Physic
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