Criterion Referenced Measures of Technical Proficiency in Maintenance Activities

1975 ◽  
Vol 19 (4) ◽  
pp. 375-380
Author(s):  
John P. Foley

The paper concerns instruments used in the determination of how effeciently maintenance men perform the various tasks of their jobs. Currently, a great deal of reliance is placed on unvalidated job-knowledge tests, theory tests, school marks, supervisors' ratings for such determination. This paper presents a composite of the results of many research and development efforts concerning the empirical validity of such instruments. These results indicate that these measurement instruments have low empirical validity. The limitations of traditional systems effectiveness measures are also discussed. Although job task performance tests (JTPT) have much higher empirical validity, such tests have had very limited use because of their relatively high costs in time, personnel and equipment. As a result of the foregoing findings, the Air Force Human Resources Laboratory (AFHRL) supported a series of efforts to develop better criterion referenced JTPT, and to attempt the development of paper and pencil symbolic substitute tests of high empirical validity. The paper describes the model battery of 48 criterion referenced JTPT, which has been developed to cover all key maintenance activities such as checkout, align/adjust, remove/replace, troubleshooting, test equipment and soldering. During this development many factors were considered including the identification and classification of tasks to be measured, the hierarchal relationship of maintenance tasks, the most effective order of their measurement and the ease of test administration. This battery was developed as a model of JTPT to be used on the job and in training. It was also intended as a battery of criterion tests for the validation of paper and pencil symbolic substitute tests. Batteries of graphic and video symbolic substitute tests were developed and given limited validations. The validation of graphic symbolic substitute tests indicated that the symbolics for all activities, with the exception of soldering, have promise. The paper discusses the requirements for additional refinement and validation for the various graphic tests. An unsuccessful effort to develop video symbolic substitute tests is also mentioned. Suggestions are made for the application of criterion referenced JTPT for the improvement of maintenance efficiency.

Author(s):  
Fumio Watari ◽  
J. M. Cowley

STEM coupled with the optical system was used for the investigation of the early oxidation on the surface of Cr. Cr thin films (30 – 1000Å) were prepared by evaporation onto the polished or air-cleaved NaCl substrates at room temperature and 45°C in a vacuum of 10−6 Torr with an evaporation speed 0.3Å/sec. Rather thick specimens (200 – 1000Å) with various preferred orientations were used for the investigation of the oxidation at moderately high temperature (600 − 1100°C). Selected area diffraction patterns in these specimens are usually very much complicated by the existence of the different kinds of oxides and their multiple twinning. The determination of the epitaxial orientation relationship of the oxides formed on the Cr surface was made possible by intensive use of the optical system and microdiffraction techniques. Prior to the formation of the known rhombohedral Cr2O3, a thin spinel oxide, probably analogous to γ -Al203 or γ -Fe203, was formed. Fig. 1a shows the distinct epitaxial growth of the spinel (001) as well as the rhombohedral (125) on the well-oriented Cr(001) surface. In the case of the Cr specimen with the (001) preferred orientation (Fig. 1b), the rings explainable by spinel structure appeared as well as the well defined epitaxial spots of the spinel (001). The microdif fraction from 20A areas (Fig. 2a) clearly shows the same pattern as Fig. Ia with the weaker oxide spots among the more intense Cr spots, indicating that the thickness of the oxide is much less than that of Cr. The rhombohedral Cr2O3 was nucleated preferably at the Cr(011) sites provided by the polycrystalline nature of the present specimens with the relation Cr2O3 (001)//Cr(011), and by further oxidation it grew into full coverage of the rest of the Cr surface with the orientation determined by the initial nucleation.


2012 ◽  
Vol 34 (3) ◽  
pp. 169-184 ◽  
Author(s):  
Hoang Thi Bich Ngoc

Vertical axis wind turbine technology has been applied last years, very long after horizontal axis wind turbine technology. Aerodynamic problems of vertical axis wind machines are discussible. An important problem is the determination of the incidence law in the interaction between wind and rotor blades. The focus of the work is to establish equations of the incidence depending on the blade azimuth, and to solve them. From these results, aerodynamic torques and power can be calculated. The incidence angle is a parameter of velocity triangle, and both the factors depend not only on the blade azimuth but also on the ratio of rotational speed and horizontal speed. The built computational program allows theoretically selecting the relationship of geometric parameters of wind turbine in accordance with requirements on power, wind speed and installation conditions.


1986 ◽  
Vol 14 (4) ◽  
pp. 201-218 ◽  
Author(s):  
A. G. Veith

Abstract This four-part series of papers addresses the problem of systematic determination of the influence of several tire factors on tire treadwear. Both the main effect of each factor and some of their interactive effects are included. The program was also structured to evaluate the influence of some external-to-tire conditions on the relationship of tire factors to treadwear. Part I describes the experimental design used to evaluate the effects on treadwear of generic tire type, aspect ratio, tread pattern (groove or void level), type of pattern (straight rib or block), and tread compound. Construction procedures and precautions used to obtain a valid and functional test method are included. Two guiding principles to be used in the data analyses of Parts II and III are discussed. These are the fractional groove and void concept, to characterize tread pattern geometry, and a demonstration of the equivalence of wear rate for identical compounds on whole tread or multi-section tread tires.


Universe ◽  
2021 ◽  
Vol 7 (7) ◽  
pp. 222
Author(s):  
Maxim Khlopov

A.D. Sakharov’s legacy in now standard model of the Universe is not reduced to baryosynthesis but extends to the foundation of cosmoparticle physics, which studies the fundamental relationship of cosmology and particle physics. Development of cosmoparticle physics involves cross-disciplinary physical, astrophysical and cosmological studies of physics Beyond the Standard model (BSM) of elementary particles. To probe physical models for inflation, baryosynthesis and dark matter cosmoparticle physics pays special attention to model dependent messengers of the corresponding models, making their tests possible. Positive evidence for such exotic phenomena as nuclear interacting dark atoms, primordial black holes or antimatter globular cluster in our galaxy would provide the selection of viable BSM models determination of their parameters.


2016 ◽  
Vol 11 (3) ◽  
pp. 802-810 ◽  
Author(s):  
Nitin Yashwant Patil ◽  
Ravi M. Warkhedkar

Purpose In the past decade, much has been written about knowledge management (KM) in the manufacturing; however, less attention has been paid to the Indian automobile ancillary industries located in Chinchwad, Pune. It is suitable to find out the relationship of the factors of the study. It helps in identifying the hierarchy of factors to be taken, and interlinking of production department with KM improves the productivity of the industries. Categorization of these principles based on their driving power (principles which hold other principles) and dependence (principles which are dependent on other principles) has also been examined for KM implementation to study the driving power and dependence power of these principles. This paper aims to determine the roadmap of KM implementation and categorize KM principles based on their driving power for manufacturing industries with the use of the interpretive structural modeling (ISM)-based model. The results indicate that the principles possessing higher driving power, such as KM, inventory control, quality control, productivity and scheduling and their interlinking. The major contribution of this research lies in the development of contextual relationship among various identified factors of KM and determination of their driving and dependence power through a single systemic framework. Design/methodology/approach In this paper, author find out the suitability ISM for Indian Automobile industries to find the relation among the variables. Findings ISM model has been developed for the hierarchy of the identified KM. As ISM model results a hypothetical hierarchy which needs a proper quantitative analysis to evaluate their percentage effectiveness in the hierarchy. Research limitations/implications It is applied to automobile industries with limited number of variables that will show the dependence variable and driving variables and their interrelations. It can be applied other fields to fine the relationship of variables. Practical implications The ISM may be used in supply chain management and total quality management to find interlinking between the variables. Originality/value The limited data collected from Pimpri Chinchwad industrial area of Pune from Maharashtra state (India).


2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
G. O. Bosire ◽  
J. C. Ngila ◽  
H. Parshotam

The extraction and determination of aliphatic and aromatic carboxylic acids as well as their influence on the aromaticity and molecularity relationship of natural organic matter (NOM) in water are reported in this study. Three solid phase extraction (SPE) sorbents were used and their extraction efficiencies evaluated after chromatographic determinations (using gas chromatography with a time of flight mass spectrometer (GC × GC-TOFMS) and liquid chromatography with organic carbon detector (LC-OCD)). More than 42 carboxylic acids were identified in raw water from the Vaal River, which feeds the Lethabo Power Generation Station, South Africa, with cooling water. The aromatic carboxylic acid efficiency (28%) was achieved by using Strata™X SPE while the highest aliphatic carboxylic acid efficiency (92.08%) was achieved by silica SPE. The hydrophobic nature of NOM in water depends on the nature of organic compounds in water, whether aromatic or aliphatic. The LC-OCD was used to assess the hydrophobicity levels of NOM as a function of these carboxylic acids in cooling water. The LC-OCD results showed that the aromatic nature of NOM in SPE filtered water followed the order Silica>Strata X>C-18. From the results, the hydrophobicity degree of the samples depended on the type and number of carboxylic acids that were removed by the SPE cartridges.


2021 ◽  
Vol 26 (3) ◽  
pp. 34-39
Author(s):  
Z. A. Goncharova ◽  
Y. Y. Pogrebnova ◽  
N. M. Yarosh ◽  
S. M.M. Sehweil

The article presents the literature review and our experience in early diagnosis of multiple sclerosis based on the updated McDonald criteria of 2017. The study included 256 patients with clinic symptoms of probable idiopathic infl ammatory demyelinating disease, including rare and atypical forms of demyelination. As a result of the study the sensitivity and specifi city of the determination of oligoclonal immunoglobulin G in the population of Rostov-on-Don was described for the fi rst time, including dependence of the duration of the disease. The relationship of clinical and MRI features of the fi rst attack of the disease with the probability of determining oligoclonal IgG in the cerebrospinal fl uid is refl ected


2015 ◽  
Vol 60 (11) ◽  
pp. 1-15
Author(s):  
Olga Leszczyńska-Luberek

The author presents the importance of the new European System of National and Regional Accounts (ESA 2010) for statistics of the general government sector. She pays particular attention to the development of data for the excessive deficit procedure. The article explains the methodological changes made to the studies in this field parallel to the ESA 2010. It discusses, among others, issues related to defining the deficit and debt of the general government, as well as the determination of a new way registering transfer of liabilities of pension schemes. It also presents the impact of new methodological guidelines for the relationship of deficit and debt to GDP in the Member States of the European Union.


Sign in / Sign up

Export Citation Format

Share Document