Insolubilization process increases enzyme stability

Enzymes complexed with polymeric matrices contain properties suggesting application to enzyme-controlled reactions. Stability of insolubilized enzyme derivatives is markedly greater than that of soluble enzymes and physical form of insolubilized enzymes is useful in column and batch processes

Temperature controller for a fluid cooled garment

An automatic controller for controlling the inlet temperature of the coolant to a fluid cooled garment without requiring skin sensors is described. Temperature is controlled by the wearer's evaporative water loss rate

Space Resources and Space Settlements

The technical papers from the five tasks groups that took part in the 1977 Ames Summer Study on Space Settlements and Industrialization Using Nonterrestrial Materials are presented. The papers are presented under the following general topics: (1) research needs for regenerative life-support systems; (2) habitat design; (3) dynamics and design of electromagnetic mass drivers; (4) asteroids as resources for space manufacturing; and (5) processing of nonterrestrial materials

The evolution problem for the 1D nonlocal Fisher-KPP equation with a top hat kernel. Part 2. The Cauchy problem on a finite interval

In the second part of this series of papers, we address the same Cauchy problem that was considered in part 1, namely the nonlocal Fisher-KPP equation in one spatial dimension, $$u_t = D u_{xx} + u(1-\phi*u),$$ where $\phi*u$ is a spatial convolution with the top hat kernel, $\phi(y) \equiv H\left(\frac{1}{4}-y^2\right)$, except that now the spatial domain is the finite interval $[0,a]$ rather than the whole real line. Consequently boundary conditions are required at the interval end-points, and we address the situations when these boundary conditions are of either Dirichlet or Neumann type. This model forms a natural extension to the classical Fisher-KPP model, with the introduction of the simplest possible nonlocal effect into the saturation term. Nonlocal reaction-diffusion models arise naturally in a variety of (frequently biological or ecological) contexts, and as such it is of fundamental interest to examine its properties in detail, and to compare and contrast these with the well known properties of the classical Fisher-KPP model

The non-local Lotka–Volterra system with a top hat kernel — Part 1:dynamics and steady states with small diffusivity

We study the dynamics of the nonlocal Lotka-Volterra system u t = Duuxx + u (1 − ϕ * u − αv), v t = Dvvxx + v (1 − ϕ * v − βu), where a star denotes the spatial convolution and the kernel ϕ is a top hat function. We initially focus on the case of small, equal diffusivities (D = Du = Dv ≪ 1) together with weak interspecies interaction (α, β ≪ 1), and specifically α, β ≪ D. This can then be extended to consider small, but unequal, diffusivities and weak interactions, with now α, β ≪ Du, Dv ≪ 1. Finally we are able to develop the theory for the situation when the diffusivities remain small, but the interactions become stronger.. In each case, we find that u and v independently develop into periodic spatial patterns that consist of separated humps on an O(1) timescale, and that these patterns become quasi-steady on a timescale proportional to the inverse diffusivity. These then interact on a longer timescale proportional to the inverse interaction scale, and approach a meta-stable state. Finally, a stable steady state is achieved on a much longer timescale, which is exponentially large relative to the preceding timescales. We are able to quantify this interaction process by determining a planar dynamical system that governs the temporal evolution of the separation between the two periodic arrays of humps on these sequentially algebraically and then exponentially long timescales. We find that, once the humps no longer overlap, the subsequent dynamics lead to a symmetric disposition of the humps, occurring on the exponentially-long timescale. Numerical solutions of the full evolution problem cannot access the behaviour on this final extreme timescale, but it can be fully explored through the dynamical system

Contact line motion for partially wetting fluids

We study the flow close to an advancing contact line in the limit of small capillary number. To take into account wetting effects, both long and short-ranged contributions to the disjoining pressure are taken into account. In front of the contact line, there is a microscopic film corresponding to a minimum of the interaction potential. We compute the parameters of the contact line solution relevant to the matching to a macroscopic problem, for example a spreading droplet. The result closely resembles previous results obtained with a slip model

Geometrical modelling of pulsed laser ablation of high performance metallic alloys

Modelling of Pulsed Laser Ablation (PLA) for the prediction of complex geometries has generally achieved limited success when aimed at large structures resulting from a high number of overlapped pulses, in particular for the ablation of metallic materials, where a significant volume of molten and re-deposited material can be present. In order to extend the capabilities of process simulation for surface prediction of PLA, this paper presents a novel problem formulation that takes into consideration the behaviour of the ejected/redeposited melt as well as the non-linear interaction between successive pulses when a laser beam is scanned along a given path. This results in a simplified mathematical framework capable of predicting features with good accuracy and low computational cost. The evolution of the depth/height at any point on the surface can be described by the convolution of a radially-varying function that represents the steady state ablation footprint (which includes also material redeposition) created by a pulsed laser scanned across the workpiece scaled according to pulse separation distance (i.e. feed speed). The model also reveals some interesting dynamics of the behaviour of redeposited material, which appears to have a lower removal threshold compared to the virgin material. This can be taken into account in a modified model formulation by introducing a linear scaling coefficient for the ablation function. Validation of the model on Ni- and Ti- superalloy for both the prediction of single trenches (i.e. scanning along straight path) at constant and variable feed speed, and overlapped trenches, is performed with an average error of less than 10%. The framework presented in the paper could provide a valuable step forward in process modelling of PLA for real-world industrial applications

AN ANALYSIS OF THE GENETIC REQUIREMENTS FOR DELAYED CUTANEOUS HYPERSENSITIVITY REACTIONS TO TRANSPLANTATION ANTIGENS IN MICE

The experiments reported herein provide ample evidence that mice, like most other mammalian species, are capable of displaying readily observable and reproducible delayed cutaneous hypersensitivity reactions indicative of transplantation immunity. By employing a variety of genetically defined strains, it has been shown that a genetic requirement for the development of a positive normal lymphocyte transfer reaction in mice is a difference between host and cell donor at the H-2 locus. By contrast, the immune lymphocyte transfer reaction consistently reflected the full range of histoincompatibility, both inclusive and exclusive of the H-2. It was incidentally discovered that erythema regularly accompanied delayed cutaneous reactions in the skins of female mice, whereas no local redness accompanied their counterparts in male skins. The influence of cutaneous erythema on the scoring of delayed skin reactions is discussed