The use of job aids for visual inspection in manufacturing and maintenance

Visual inspection is a task regularly seen in manufacturing applications and is still primarily carried out by human operators. This study explored the use of job aids (anything used to assist the operator with the task, such as lists, check sheets or pictures) to assist with visual inspection within a manufacturing facility that inspects used parts. Job aids in the form of inspection manuals were used regularly during the inspection process, and how accurately they were followed was dependent on a number of factors such as size of part, experience of the operator, and accuracy of the inspection manuals. If the job aids were well structured, well written and accessible, then the inspectors were seen to follow them, however for certain jobs inspectors were seen to change the inspection order making inspection more efficient. The findings of the study suggest that prior experience can help in designing efficient, easy to use job aids and that a collaborative approach to design as well as using pictorial examples for comparison purposes would improve the inspection process

The Comparison of the Effects of Two Training Methods to Increase Muscular Strength, Endurance, Power, Speed and Agility of Adolescent Boys of Fertile High School

The purpose of this study was to compare changes observed during an experimental period involving two training methods utilized to increase muscular strength, endurance, power, speed, and agility. The subjects selected for this study were freshman and sophomore students at the High School of Fertile, Minnesota enrolled in the required physical education classes. This selection was a random choice of one weight training group and one endurance training group. Both groups participated in their respective exercise programs for a period of eight weeks. Each group was tested on six test items consisting of push-ups, burpees, shuttle run, broad jump, pull-ups, and sit-ups. These test items were administered at the beginning of the experimental period and after the eight weeks of training. Comparisons were made between the mean differences within each group on each test item as indicated by the pre-test and re-test. The null hypothesis was assumed with respect to the differences withing groups. This hypothesis was tested tith the t technique for the difference between means derived from correlated scores from small samples. Comparisons were also made between the weight training group and endurance training group by testing the significance of the difference between the mean differences found with the groups. The between group comparison used the t technique for correlated data from small samples. Based on the results of this study, both groups changed significantly on test items within the groups. However, the treatment of the data with respect to the differences between the two groups indicated a significant difference at the .05 level of confidence in the push-up test item

Hen Cackle Rag

Title in bold red letters above an illustration of henshttps://scholarsjunction.msstate.edu/cht-sheet-music/13944/thumbnail.jp

Pressure distributions from high Reynolds number transonic tests of an NACA 0012 airfoil in the Langley 0.3-meter transonic cryogenic tunnel

Tests were conducted in the 2-D test section of the Langley 0.3-meter Transonic Cryogenic Tunnel on a NACA 0012 airfoil to obtain aerodynamic data as a part of the Advanced Technology Airfoil Test (ATAT) program. The test program covered a Mach number range of 0.30 to 0.82 and a Reynolds number range of 3.0 to 45.0 x 10 to the 6th power. The stagnation pressure was varied between 1.2 and 6.0 atmospheres and the stagnation temperature was varied between 300 K and 90 K to obtain these test conditions. Tabulated pressure distributions and integrated force and moment coefficients are presented as well as plots of the surface pressure distributions. The data are presented uncorrected for wall interference effects and without analysis

Almost principal minors of inverse M-matrices

AbstractIt is well known that if an inverse M-matrix has a 0 entry, then it must be reducible and thus have many more 0 entries. This property is actually a special case of a deeper phenomenon that might be loosely described as relations among vanishing almost principal minors in an inverse M-matrix. This phenomenon encompasses both minors of nested dimension (a certain loose monotonicity) and minors of the same size in loosely related positions. This phenomenon is limited to almost principal minors and, where possible, converses and examples are given to show the limit of the extent of this phenomenon. It is also shown that if one almost principle minor is contained in another, then the magnitude of the former is larger than that of the latter

Inverse M-matrices, II

AbstractThis is an update of the 1981 survey by the first author. In the meantime, a considerable amount has been learned about the very special structure of the important class of inverse M-matrices. Developments since the earlier survey are emphasized, but we have tried to be somewhat complete; and, some results have not previously been published. Some proofs are given where appropriate and references are given for others. After some elementary preliminaries, results are grouped by certain natural categories

The symmetric inverse M-matrix completion problem

AbstractNecessary and sufficient conditions are given on the data for completability of a partial symmetric inverse M-matrix, the graph of whose specified entries is a cycle, and these conditions coincide with those we identify to be necessary in the general (nonsymmetric) case. Graphs for which all partial symmetric inverse M-matrices have symmetric inverse M-matrix completions are identified and these include those that arise in the general (positionally symmetric) case. However, the identification of all such graphs is more subtle than the general case. Finally, we show that our new cycle conditions are sufficient for completability of all partial symmetric inverse M-matrices, the graph of whose specified entries is a block graph

Blackbody radiation shift in a 43Ca+ ion optical frequency standard

Motivated by the prospect of an optical frequency standard based on 43Ca+, we calculate the blackbody radiation (BBR) shift of the 4s_1/2-3d_5/2 clock transition, which is a major component of the uncertainty budget. The calculations are based on the relativistic all-order single-double method where all single and double excitations of the Dirac-Fock wave function are included to all orders of perturbation theory. Additional calculations are conducted for the dominant contributions in order to evaluate some omitted high-order corrections and estimate the uncertainties of the final results. The BBR shift obtained for this transition is 0.38(1) Hz. The tensor polarizability of the 3d_5/2 level is also calculated and its uncertainty is evaluated as well. Our results are compared with other calculations.Comment: 4 page

Magnetically Retained Relief Valve

A pressure relief valve includes a housing having a fluid inlet and at least one fluid outlet. A first structure mounted in the housing and fixed in relation thereto is in magnetic attraction with a second structure coupled to a piston disposed in a portion of the housing. The piston defines a chamber disposed adjacent to the fluid outlet(s) throughout the piston's stroke. The piston includes a sealing element providing a sealing force to prevent flow through the valve. The sealing force is independent of the magnetic attraction force between the first and second structures