Automatic sets of rational numbers

The notion of a k-automatic set of integers is well-studied. We develop a new notion - the k-automatic set of rational numbers - and prove basic properties of these sets, including closure properties and decidability.Comment: Previous version appeared in Proc. LATA 2012 conferenc

Machine Tool Characteristics

Cutting tool characteristics were examined with respect to the effects of the machine controlled parameters and tool geometry on cutting phenomenon. This subject has been a matter of prolonged interest to machine tool designers and users alike as it is the basis on which tool life and hence general metal cutting economics are evolved. Most previous research works concentrated on temperature generation usually without recourse to the combined effects of the machine controlled parameters and tool geometry. This missing link is supplied in this work. Basically, the findings in this work show that the cutting speed has a great influence on the forces and temperature and hence on tool life as well as the machining economics. The feed has similar but less influence on these quantities. The cutting efficiency expressed as compression ratio is also influenced by both the speed and feed. However, the influences of speed and feed on the compression ratio are in opposing directio

Machinery and Equipment Valuation

Valuation (appraisal) gives an unbiased opinion of value or other physical attributes of identified property. Value, on the other hand, is the monetary worth of property, goods or services. The Machinery and Technical Specialties (MTS) Committee of the American Society of Appraisers (ASA) established methods for valuation of property including machinery and equipment. These methods conform to the Uniform Standards of Professional Appraisal Practice (USPAP). Valuation of property and indeed machinery and equipment is necessary for various purposes including ownership change, partnerships, mergers and acquisitions. The Industrial Inspectorate Department (IID) of the Federal Ministry of Industry in conformity with the Institute of Appraisers and cost Engineers (IACE) of the Nigerian Society of Engineers (NSE) Internalized the valuation process in carrying out the mandate of determining the investment valuation of capital undertakings with the view to issuing acceptance certificate for capital allowance purposes and certificate of value for equity contribution. This paper sets out to streamline the various valuation methods as a way of complementing the existing valuation process. The application of a combination of these valuation methods is recommended to arrive at an unbiased opinion of value of any property and indeed machinery and equipmen

Monte Carlo Simulation of Bottomhole Coordinates in Directional Drilling

Increasing interest is now focused on directional survey and on the uncertainty inherent in the calculation of the bottom hole coordinates because many wells are drilled from offshore platforms and urban drill sites. These uncertainties may result from errors due to the limitation on instrument accuracy, unconcentric positioning of the tools with the borehole and may include reading errors. It is therefore necessary to develop methods for determining the cumulative effect of these errors on the bottomhole coordinates and reducing such effects. In this study, Monte Carlo simulation method is adopted as a technique of achieving this objective. The inclination angle, Ii and the azimuthal angle, Ai are treated as random variables with their associated probability density function P(Ii) and P(Ai) respectively. These represent the distributions of the potential survey measurements in a given well. The parameter Si which represents the linear segment constituting the curvilinear axis of the wellbore is treated deterministically since its values can be measured accurately. Treating Ii and Ai as random variables in a wellbore model is justified by the fact that both of them, though deterministic, can hardly ever be measured accurately in any subsurface survey. The results of the study show that the probability of the estimated bottomhole positions being true is nearly unity for vertical well and slightly less for directional well

Performance and evaluation of the Viking lander camera performance prediction program

A computer program is described for predicting the performance of the Viking lander cameras. The predictions are primarily concerned with two objectives: (1) the picture quality of a reference test chart (of which there are three on each lander) to aid in diagnosing camera performance; and (2) the picture quality of cones with surface properties of a natural terrain to aid in predicting favorable illumination and viewing geometries and operational camera commands. Predictions made with this program are verified by experimental data obtained with a Viking-like laboratory facsimile camera

Building A Viable Organisation through an Effective organisation strategy

Effeetivt: organizational strategy is important to ensure that the organization chart an effective course towards the org,mi:Lational mission, goal~ and objectives. The relationship between an organization and its cnvimnmcn1 ;, a determinant of type of strategy suitable for its viability. The purpose of thi~ ~tudy ts to determine the extent to which l'igerian Association of Small Scale Industrialists (NASSI) employs strategic planning and its impacts on their organiz:ltions. The methods used in this study arc both secondary and primary means of data collection. Books, journals and :~rticles on small scale industries were read. 150 questionnaires were self administered to members of Nassi in their monthly meeting. The analysis of the results pointed out that every organization that imbibes the culture of strategic plannmg becomes more viable. Almost all the scholars stretched the fact that effective strategy in an organization is the responsibility of the top management. The management of an organization must be creative with their strategies to be abk to cope with the ehallt:nges of sustaining and making their organization viabl

A systematic review of ICD complications in randomised controlled trials versus registries: is our 'real-world' data an underestimation?

Implantable cardioverter defibrillator (ICD) implantation carries a significant risk of complications, however published estimates appear inconsistent. We aimed to present a contemporary systematic review using meta-analysis methods of ICD complications in randomised controlled trials (RCTs) and compare it to recent data from the largest international ICD registry, the US National Cardiovascular Data Registry (NCDR). PubMed was searched for any RCTs involving ICD implantation published 1999-2013; 18 were identified for analysis including 6433 patients, mean follow-up 3 months-5.6 years. Exclusion criteria were studies of children, hypertrophic cardiomyopathy, congenital heart disease, resynchronisation therapy and generator changes. Total pooled complication rate from the RCTs (excluding inappropriate shocks) was 9.1%, including displacement 3.1%, pneumothorax 1.1% and haematoma 1.2%. Infection rate was 1.5%.There were no predictors of complications but longer follow-up showed a trend to higher complication rates (p=0.07). In contrast, data from the NCDR ICD, reporting on 356 515 implants (2006-2010) showed a statistically significant threefold lower total major complication rate of 3.08% with lead displacement 1.02%, haematoma 0.86% and pneumothorax 0.44%. The overall ICD complication rate in our meta-analysis is 9.1% over 16 months. The ICD complication reported in the NCDR ICD registry is significantly lower despite a similar population. This may reflect under-reporting of complications in registries. Reporting of ICD complications in RCTs and registries is very variable and there is a need to standardise classification of complications internationally

Verification of Machinery Salvage Value Function

Salvage value or resale value is one of the cost components of machinery replacement models. Some replacement models exclude salvage value in the build-up of cost. Yet it is the value that is adversely affected by deterioration. Various mathematical formulas for machinery salvage value have been formulated. The formula for salvage value presented by Lake and Muhlemann is of interest. It is presented in an exponential form. The suitability of this function to our industrial environment has to be justified bearing in mind that some assets have little or no secondhand value. To ensure a balanced investigation, efforts are made to obtain salvage values for motor grader, representing large scale industrial environment and photocopier, representing small and medium scale industrial environment. It is difficult to obtain salvage values because records are hardly kept for such values. However, two sets of salvage values are obtained for each of the machines. One set is for the calibration of the salvage value function by Lake and Muhlemann while the other is for comparison between the measured and predicted salvage values. This paper therefore sets out to investigate and verify the suitability of salvage value function formulated by Lake and Muhlemann to our industrial environment. It is hoped that the investigation will lead to a better understanding of the salvage value function for proper application in our industrial environment