Element Count Research Articles

Statistical models for surface renewal in heat and mass transfer: Part II. Techniques for measurement of age distribution at transport surfaces

AbstractMethods are developed to estimate the mean residence time and the average transport coefficient of elements at a transporting surface from observations of only total element counts, rather than from specific observations of individual elements. The accuracy of the methods is demonstrated in Monte Carlo simulated processes and experimentally at the wall of a gas‐fluidized bed.

Two Theorems on Positive-Real Functions and Their Application to the Synthesis of Symmetric and Antimetric Filters

It is first shown that the power gain of a filter which has been partitioned into two component parts may be expressed in terms of a formula involving only the two impedances seen looking to the left and the right of the common junction. By imposing the constraints of symmetry and antimetry this formula leads quite naturally to two global equations for positive-real (pr) functions. Theorems 1 and 2 present necessary and sufficient conditions for the existence of solutions. Moreover, the construction of these pr functions is made to depend on two algorithms of an extremely simple character. The theory is fully illustrated by means of four worked, nontrivial examples. Finally, it is pointed out that synthesis by bisection is often wasteful of reactances (especially in the symmetric case), and a careful count of elements is presented for antimetric filters.

Digital Period Meter Utilizing Magnetic Core

A new type of reactor period meter utilizing multi-pulse magnetic counter as a neutron level comparator is described. The counter, which is initially counted for a unit interval at any time, is subtracted by one count for each input pulse after a fixed time-lag. The time required to empty the counter may be converted to reactor period by usage of a logic matrix. Ring ferrite cores are used as high speed shaping element and high speed pental counting element, and Deltamax core (50 Ni-Fe alloy) as decimal counting one. These pental and decimal counting circuits are originated from dividing the total magnetic flux amount (from negative to positive saturation) into 5 and 10 steps, respectively, and changing the flux level in the magnetic core stepwise corresponding to each input pulse. The period meter construction with magnetic cores results in increasing simplicity and reliability, and is much superior to the conventional circuit with a logarithmic amplifier and a differential circuit.

CELLULAR SPECIFICITY IN THE HOMOGRAFT REACTION.

The present study offers direct evidence that cells from the regional lymph node draining first-set skin homografts in rabbits participate in the lymphoid infiltrate at distant sites of graft rejection. With the use of a newly devised method of injection, adequate amounts of tritiated thymidine could be confined to the reactive regional node, other dividing cells of the host remaining unlabeled. It was thus possible to detect the appearance of this uniquely labeled population of cells at remote test sites on the same animal, obviating the necessity for cell transfer. Under these conditions differential counts of the lymphoid elements failed to show a preponderance of labeled cells in the infiltrate accompanying homologous, compared with unrelated control, graft rejection. These results, together with other recently reported data, suggest that the specificity of the homograft reaction is probably dictated by some humoral factor that acts in concert with recently proliferated lymphoid cells to accomplish graft rejection.

Filth in Fruit Paste

Abstract Development of a method for recovering all types of filth encountered in fruit paste has been initiated. A number of people were consulted about their experiences in examinations of fig paste by method 36.053 and their efforts to improve recovery of rodent hairs, fly eggs, and maggots by supplementary or substitute procedures. Their answers indicate that a method incorporating extensive digestion of the fruit tissue to liberate filth elements, followed by sieving on a No. 140 screen and washing forcibly with a spray of water to reduce the amount of fruit tissue, then examining the sieve residue microscopically for insects and hairs, appears feasible. Application of this procedure to a commercial straight Calimyrna fig paste resulted in improved filth recovery compared to the AOAC method but proved time-consuming due to the amount of residual fig tissue on the sieve. Kerosene-water flotation treatment of the washed residue on the screen expedited the counting of filth elements, giving recoveries intermediate to those obtained by the AOAC method and direct microscopic examination of digested and sieved residues. It is recommended that the study be continued.

Method for absolute measurement of the activity of beta-radiating liquids

The advantages of the above method of absolute measurements of β-active liquids consist of: 1. The absence of any intermediate chemical operations in preparing samples; 2. The absence of such procedures as drying the source, with the related errors which are difficult to estimate, and are due to possible losses owing to the chemical instability of the precipitated preparation or of the isotope exchange; 3. The absence of any corrections for self-absorption, back-scattering, etc. The efficiency of the compensated element counting is virtually equal to 100%; 4. High accuracy; 5. Speed of operation. The duration of one measurement, including the preparation of the sample, amounts to no more than 1 hr as compared with 10–15 hr required for other methods.

On the Loop- and Node-Analysis Approaches to the Simulation of Electrical Networks

The number of integrators in an analog-computer setup should be equal to the order of the differential equation describing the system. This paper presents a new procedure for tracing the loop currents which results in one-to-one correspondence between the number of integrators in the stimulation setup and the count of independent energy-storing elements in the network, i.e., the degree of the system's characteristic equation. The generality of the procedure proves that it is always possible to trace the loop currents in such a way that excess integrators are avoided. The loop-analysis and the branch-variables-analysis approaches are discussed and examples given.

Clinical Study of Bone Marrow by the Method of Sternal Puncture

The material was secured by sternal puncture by a technique similar to that of Arinkin. More than 50 cases were used representing a wide variety of clinical conditions. Smears made from the marrow material were stained with Wright's stain, Cresyl blue reticulocyte stain, Giemsa stain and peroxidase stains, no variations in technique being made from that of peripheral blood smears. This report is limited to a discussion of the Wright stained preparations. The marrow cells are well-preserved and stained. Differential counts of the marrow cell elements have been made. The average of 7 cases with a normal peripheral blood picture was the following cells: Myeloblasts 2.4%; myelocytes 7%; Jung Kernige 6.7%; Stag Kernige 14%; II Segment Neutrophiles 10%; III Segment Neutrophiles 6.3%; IV, V, etc., Segment Neutrophiles 1.1%; Eosinophiles 1%; Basophiles 0.3%; Monocytes and Reticuloendothelial elements 9%; Lymphoid Cells 24.9%; Megaloblasts 5.2%; Normoblasts 6.9%; Primitive Cells 2.6%. These findings agree rather closely with those of Arinkin on similar types of cases. The high percentage of immature granulocytes in our counts confirms the concept of Arneth and Schilling that the neutrophilic nucleus changes progressively with age from the round to the segmented form. The high percentage of juveniles and stabs confirms the idea that these are “young” granulocytes. Cells indistinguishable by Wright's stain from the lymphocytes of peripheral blood are present in practically all of our bone marrow preparations. These we have designated as lymphoid cells. Certain small primitive cells and young myeloblasts may be included in this group. The percentage of lymphoid cells is definitely greater than would be expected from the possible contamination with lymphocytes of peripheral blood. We have not attempted a separation of lymphoblasts from myeloblasts in the Wright stain preparations— all are termed myeloblasts except in the case of lymphatic leukemia.

A New Method for Determining the Proportion of the Length of a Tracheid that is in Contact with Rays

1. A simple method has been suggested for determining the ratio between the length of tracheid-ray to total tracheid-wall contact that requires only the counting of structural elements. 2. A comparison between the results obtained with this method and with the direct-measurement method is given. 3. The values for this ratio obtained for all the different species of softwood examined range from 0.072 to 0.288. Values of the ratio for a given species vary considerably less, and, for different parts of the same specimen, still less. There is no significant difference between the values for summerwood and for springwood.