Letter to nephew, 05/16/1881

Letter from Daniel D. Whedon to nephew. One of two dated May 16, 1881.

The formulation, testing and stability of 16% fat cream liqueurs

Cream liqueurs manufactured by a one-step process, where alcohol was added before homogenisation, were more stable than those processed by a two -step process which involved addition of alcohol after homogenisation. Using the one-step process, it was possible to produce creaming-stable liqueurs by using one pass through a homogeniser (27.6 MPa) equipped with "liquid whirl" valves. Test procedures to characterise cream liqueurs and to predict shelf life were studied in detail. A turbidity test proved simple, rapid and sensitive for characterising particle size and homogenisation efficiency. Prediction of age thickening/gelation in cream liqueurs during incubation at 45 °C depended on the age of the sample when incubated. Samples that gelled at 45 °C may not do so at ambient temperature. Commercial cream liqueurs were similar in gross chemical composition, and unlike experimentally produced liqueurs, these did not exhibit either age-gelation at ambient or elevated temperatures. Solutions of commercial sodium caseinates from different sources varied in their calcium sensitivity. When incorporated into cream liqueurs, caseinates influenced the rate of viscosity increase, coalescence and, possibly, gelation during incubated storage. Mild heat and alcohol treatment modified the properties of caseinate used to stabilise non-alcoholic emulsions, while the presence of alcohol in emulsions was important in preventing clustering of globules. The response to added trisodium citrate varied. In many cases, addition of the recommended level (0.18%) did not prevent gelation. Addition of small amounts of NaOH with 0.18 % trisodium citrate before homogenisation was beneficial. The stage at which citrate was added during processing was critical to the degree of viscosity increase (as opposed to gelation) in the product during 45 °C incubation. The component responsible for age-gelation was present in the milk-solids non fat portion of the cream and variations in the creams used were important in the age-gelation phenomenon Results indicated that, in addition to possibly Ca++, the micellar casein portion of serum may play a role in gelation. The role of the low molecular weight surfactants, sodium stearoyl lactylate and monodiglycerides in preventing gelation, was influenced by the presence of trisodium citrate. Clustering of fat globules and age-gelation were inhibited when 0.18 % citrate was included. Inclusion of sodium stearoyl lactylate, but not monodiglycerides, reduced the extent of viscosity increase at 45 °C in citrate containing liqueurs.

Artificial opal photonic crystals and inverse opal structures - fundamentals and applications from optics to energy storage

Photonic crystals (PhCs) influence the propagation of light by their periodic variation in dielectric contrast or refractive index. This review outlines the attractive optical qualities inherent to most PhCs namely the presence of full or partial photonic band gaps and the possibilities they present towards the inhibition of spontaneous emission and the localization of light. Colloidal self-assembly of polymer or silica spheres is one of the most favoured and low cost methods for the formation of PhCs as artificial opals. The state of the art in growth methods currently used for colloidal self-assembly are discussed and the use of these structures for the formation of inverse opal architectures is then presented. Inverse opal structures with their porous and interconnected architecture span several technological arenas - optics and optoelectronics, energy storage, communications, sensor and biological applications. This review presents several of these applications and an accessible overview of the physics of photonic crystal optics that may be useful for opal and inverse opal researchers in general, with a particular emphasis on the recent use of these three-dimensional porous structures in electrochemical energy storage technology. Progress towards all-optical integrated circuits may lie with the concepts of the photonic crystal, but the unique optical and structural properties of these materials and the convergence of PhC and energy storage disciplines may facilitate further developments and non-destructive optical analysis capabilities for (electro)chemical processes that occur within a wide variety of materials in energy storage research.

Multiscale optics for enhanced light collection from a point source.

High-efficiency collection of photons emitted by a point source over a wide field of view (FoV) is crucial for many applications. Multiscale optics offer improved light collection by utilizing small optical components placed close to the optical source, while maintaining a wide FoV provided by conventional imaging optics. In this work, we demonstrate collection efficiency of 26% of photons emitted by a pointlike source using a micromirror fabricated in silicon with no significant decrease in collection efficiency over a 10 mm object space.

Enhancing imaging systems using transformation optics.

We apply the transformation optical technique to modify or improve conventional refractive and gradient index optical imaging devices. In particular, when it is known that a detector will terminate the paths of rays over some surface, more freedom is available in the transformation approach, since the wave behavior over a large portion of the domain becomes unimportant. For the analyzed configurations, quasi-conformal and conformal coordinate transformations can be used, leading to simplified constitutive parameter distributions that, in some cases, can be realized with isotropic index; index-only media can be low-loss and have broad bandwidth. We apply a coordinate transformation to flatten a Maxwell fish-eye lens, forming a near-perfect relay lens; and also flatten the focal surface associated with a conventional refractive lens, such that the system exhibits an ultra-wide field-of-view with reduced aberration.

Instrument independent diffuse reflectance spectroscopy.

Diffuse reflectance spectroscopy with a fiber optic probe is a powerful tool for quantitative tissue characterization and disease diagnosis. Significant systematic errors can arise in the measured reflectance spectra and thus in the derived tissue physiological and morphological parameters due to real-time instrument fluctuations. We demonstrate a novel fiber optic probe with real-time, self-calibration capability that can be used for UV-visible diffuse reflectance spectroscopy in biological tissue in clinical settings. The probe is tested in a number of synthetic liquid phantoms over a wide range of tissue optical properties for significant variations in source intensity fluctuations caused by instrument warm up and day-to-day drift. While the accuracy for extraction of absorber concentrations is comparable to that achieved with the traditional calibration (with a reflectance standard), the accuracy for extraction of reduced scattering coefficients is significantly improved with the self-calibration probe compared to traditional calibration. This technology could be used to achieve instrument-independent diffuse reflectance spectroscopy in vivo and obviate the need for instrument warm up and post∕premeasurement calibration, thus saving up to an hour of precious clinical time.

Superresolution: an ill-posed problem in Fourier optics

info:eu-repo/semantics/published

On the problems of object restoration and image extrapolation in optics

In this paper we consider the problems of object restoration and image extrapolation, according to the regularization theory of improperly posed problems. In order to take into account the stochastic nature of the noise and to introduce the main concepts of information theory, great attention is devoted to the probabilistic methods of regularization. The kind of the restored continuity is investigated in detail; in particular we prove that, while the image extrapolation presents a Hölder type stability, the object restoration has only a logarithmic continuity. © 1979 American Institute of Physics.

On the regularization of linear inverse problems in Fourier optics

info:eu-repo/semantics/published

Applied Inverse Problems in Optics

info:eu-repo/semantics/published

Reproduction of algebraic structures by 16-18 year old students

In this exploratory research we analyze the structure sense evidenced by 33 secondary students (16-18 years old) in tasks requiring to reproduce the structure of given algebraic expressions. The expressions used were algebraic fractions related to algebraic identities. There were big differences between the students performance which allowed differencing levels in students´ structure sense. Questions and conjectures to be addressed in future research are presented.

Imátgenes 16, 17 y 18

Hoy vengo a exponer una queja. Cada día, casi a todas horas, y, prácticamente en todo el mundo, soy maltratado. Y ese maltrato no es fruto del azar. Obedece patrones bien determinados de antemano por las voluntades de mis torturadores. Reconozco que a veces no es un maltrato auténtico y que incluso puede divertirme. Eso me mantiene en forma y me da un dinamismo que mi posición habitual no sugiere.

Códigos secretos: otra forma de aplicar las matrices en bachillerato (16-18)

Tras una breve introducción para hacer referencia a distintos tipos de códigos secretos, el articulo estudia con detalle, esquemáticamente y mediante ejemplos, los códigos matriciales. Se expone, además, una forma de automatizar dichos códigos en el aula, mediante un programa escrito en dBASE III Plus. La parte final consta de unas preguntas sobre sus posibilidades didácticas.

Bases para un planteamiento actual de la geometría en la enseñanza secundaria obligatoria (12-16)

Propuesta para un planteamiento de la Geometría en la Enseñanza Secundaria Obligatoria (12-16), siguiendo las directrices del Diseño Curricular Base.

[Book Review] Vardah Shiloh, Millon 'Ivri-'Arami-'Aššuri bs-Lahag Yihude Zaxo (A New Neo-Aramaic Dictionary: Jewish Dialect of Zakho). Volume I: 'alef—nun\ Volume II: samex-tav. V. Shilo (16 Ben-Gamla Street), Jerusalem 1995. Pp. xiv + 488 (Vol. I); 489-963 (Vol. II). (Modern Hebrew, Zakho Jewish Neo-Aramaic).

Review of: Vardah Shiloh, Millon 'Ivri-'Arami-'Aššuri bs-Lahag Yihude Zaxo (A New Neo-Aramaic Dictionary: Jewish Dialect of Zakho). Volume I: 'alef—nun\ Volume II: samex-tav. V. Shilo (16 Ben-Gamla Street), Jerusalem 1995. Pp. xiv + 488 (Vol. I); 489-963 (Vol. II). (Modern Hebrew, Zakho Jewish Neo-Aramaic). Hbk.