Improved rack and pinion drive

Set Up

A typical rack and pinion drive set is comprised of a rack and a pinion. There is an inter-tooth clearance between the mating teeth of the rack and the pinion, which has advantages and disadvantages. The disadvantage of this clearance is the errors that occur in the positioning of the machine tool during set-up. Elimination of clearance between teeth is possible by using a pinion drive with two pinions. This ensures continuous contact between the teeth, regardless of the direction of machine movement. These are found on new machines, while older machines do not have such a solution. This paper presents a solution with two pinions, which can be used in such older machines and which makes it possible to achieve qualitative parameters that were not possible before.

Perceived Advantages and Disadvantages of Nonsmoking Sections in Restaurants: Topics to Communicate to Restaurateurs

International Quarterly of Community Health Education ◽

10.2190/69dk-716f-k1rc-hdqy ◽

1989 ◽

Vol 9 (4) ◽

pp. 299-304 ◽

Author(s):

Gerardo Marin ◽

Raymond J. Gamba

Keyword(s):

San Francisco ◽

Set Up

Results from interviews with 315 restaurateurs in San Francisco are reported on their perceptions of the advantages and disadvantages of having a nonsmoking section in their restaurants. The major advantage of having a nonsmoking section independent of whether one is present is to please customers. The most commonly mentioned disadvantage for those restaurants with nonsmoking sections is the fact that it is inconvenient to clients' seating preferences primarily because it breaks up dining parties. Efforts at convincing restaurateurs to set up nonsmoking sections may be directed at pointing out savings in cleaning, labor, insurance, and the improvement of the health of their employees together with meeting clients' desires.

CLASSIFICATION OF HAND SPLINTING

Hand Surgery ◽

10.1142/s0218810402001199 ◽

2002 ◽

Vol 07 (02) ◽

pp. 209-213 ◽

Cited By ~ 5

Author(s):

Simon K. M. Wong

Keyword(s):

Environmental Factors ◽

Classification System ◽

Single System ◽

Logical Deduction ◽

American Society ◽

Set Up ◽

New System ◽

Rote Memory

The terminology in describing splint or orthosis has been reviewed but there is no one single system adopted universally. Joint efforts by doctors, therapists and orthotists had been set up to review the classification of splint. Four ways of classifying hand splints have been introduced: namely, eponym, acronym, descriptive classification system and the classification system proposed by the American Society of Hand Therapists. These systems include the use of rote memory or logical deduction in grouping of splints. This paper describes the advantages and disadvantages of each classification system. Neither one of the systems stands out to be the best. A combination of the advantages of different systems, such as precision and logical deduction, may be an option for developing a new system. Moreover, communication, documentation and other environmental factors should also be considered.

Beak Trimming Handbook for Egg Producers

10.1071/9780643093539 ◽

2006 ◽

Cited By ~ 3

Author(s):

Phil Glatz ◽

Michael Bourke

Keyword(s):

Quality Control ◽

Best Practice ◽

Egg Laying ◽

Future Developments ◽

Maximum Productivity ◽

Comprehensive Information ◽

Set Up ◽

Beak Trimming ◽

Farm Biosecurity

The Beak Trimming Handbook for Egg Producers is a straightforward, practical guide to beak trimming of egg-laying hens to minimise cannibalism. It provides comprehensive information on why birds peck and how pecking can lead to problems like cannibalism; the methods available to beak trim birds; why a particular method should be chosen; and at what age birds may be trimmed. The book addresses quality control of beak trimming, enabling egg producers to be confident that equipment is properly set up, that birds are handled and trimmed according to best practice and farm biosecurity is maintained. Management of birds following beak trimming, to protect of the welfare of the birds and to ensure maximum productivity, is covered in detail. Best-practice, current methods of beak trimming, costs of trimming and ways to reduce the use of trimming are examined, along with expected future developments. The advantages and disadvantages of beak trimming are fully explored, covering both public and industry attitudes to the operation. Alternatives to beak trimming are canvassed to understand how the use of fitted devices, enrichment devices, abrasives, low lighting and the choice of low-pecking strains of birds can reduce the need for beak trimming. Finally, the book discusses strategies for minimising cannibalism and how the chosen strategy may be documented and justified. Please note that this book is spiral-bound.

Mathematical Models with Buckling and Contact Phenomena for Elastic Plates: A Review

Mathematics ◽

10.3390/math8040566 ◽

2020 ◽

Vol 8 (4) ◽

pp. 566

Author(s):

Aliki D. Muradova ◽

Georgios E. Stavroulakis

Keyword(s):

Mathematical Models ◽

Initial Conditions ◽

Nonlinear Partial Differential Equations ◽

Composite Plates ◽

Contact Problems ◽

Elastic Plates ◽

Contact Models ◽

Set Up ◽

Unilateral Contact Problems

A review of mathematical models for elastic plates with buckling and contact phenomena is provided. The state of the art in this domain is presented. Buckling effects are discussed on an example of a system of nonlinear partial differential equations, describing large deflections of the plate. Unilateral contact problems with buckling, including models for plates, resting on elastic foundations, and contact models for delaminated composite plates, are formulated. Dynamic nonlinear equations for elastic plates, which possess buckling and contact effects are also presented. Most commonly used boundary and initial conditions are set up. The advantages and disadvantages of analytical, semi-analytical, and numerical techniques for the buckling and contact problems are discussed. The corresponding references are given.

Study on Application of Grey System Theory in Fatigue Span Design of Machine Tool Axles

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.201-203.1156 ◽

2011 ◽

Vol 201-203 ◽

pp. 1156-1160 ◽

Author(s):

Jin Xu ◽

Chun Xia Wang

Keyword(s):

Differential Equation ◽

System Theory ◽

Machine Tool ◽

Stress Level ◽

Grey System Theory ◽

Grey System ◽

Discrete Function ◽

Mechanical Parts ◽

Set Up ◽

Relationship Of

The interdependent relationship of fatigue stress and span was regarded as a grey system using grey system theory and method. The stress level of fatigue test was uniformly divided into many grades and the whiting value of safe span was found out. A smooth discrete function was formed based on one accumulation of safe span value series. Therefore, the model of grey system was set up and the differential equation of grey system was solved. The accuracy of model was improved by revising the residual model. The safe span value at every stress level could be calculated using the reduction model of the grey system. It provided a new way for the safe span calculation of mechanical parts, which would be of great application value.

Assessments of Upper Limb Ability following Stroke: A Review

British Journal of Occupational Therapy ◽

10.1177/030802260807101006 ◽

2008 ◽

Vol 71 (10) ◽

pp. 427-437 ◽

Cited By ~ 10

Author(s):

Tennille J Rowland ◽

Louise Gustafsson

Keyword(s):

Clinical Practice ◽

Psychometric Properties ◽

Upper Limb ◽

Clinical Utility ◽

Reliability And Validity ◽

Psychometric Testing ◽

Inclusion Criteria ◽

Test Items ◽

Set Up

The aim of this paper was to review the psychometric properties and clinical utility of assessments of upper limb ability following stroke. Upper limb ability was defined as the use of the arm in meaningful activity. The database searches identified 13 assessments of upper limb ability. The inclusion criteria were (a) an evaluation of upper limb ability post-stroke, (b) a quantitative assessment yielding a numerical score, (c) able to be administered by an occupational therapist and (d) published information building on the results of a review in 2001. The assessments included were reviewed with respect to the ability measured, equipment required, evidence of reliability and validity, and advantages and disadvantages of use. Seven assessments satisfied the inclusion criteria. These assessments have undergone varying degrees of psychometric testing as outcome measures for upper limb recovery and all demonstrate at least adequate levels of reliability and validity. There is variation in the availability of instruction manuals and time commitments for test administration. All test items are generally available and inexpensive, enabling departments to set up the assessments with minimal financial outlay. The assessments described are regularly used in research and all demonstrate psychometric properties that suggest that they could be incorporated into clinical practice. Occupational therapists are encouraged to consider how they may include these assessments into their own clinical practice. An important step in this process may be further research into the clinical utility of these assessments.

Machine Tool Tests and Alignments

Proceedings of the Institution of Mechanical Engineers ◽

10.1243/pime_proc_1938_138_010_02 ◽

1938 ◽

Vol 138 (1) ◽

pp. 59-119

Author(s):

Georg Schlesinger

Keyword(s):

Machine Tool ◽

International Federation ◽

National Standards ◽

Measuring Apparatus ◽

Balance Sheets ◽

Milling Machines ◽

Grinding Machines ◽

Fine Boring ◽

Set Up ◽

Agricultural Machines

Limits and tolerances are the basis of all machine manufacture. Fourteen European countries adopted the system known as the ISA (International Federation of National Standards Associations) in December 1936; the system covers all grades of finish from the finest roller bearings to rough agricultural machines. Certain fixed principles of measurement must be observed, both in the manufacture of new machines and in the repair of old ones; for instance, extremely fine boring and grinding machines and jig borers are now obtainable and can be used equally for the manufacture of a new motor car or for the overhauling of an old one. Before a satisfactory basis for the establishment of correct limits for the manufacture of, say, drilling machines, lathes, and milling machines, the deformations set up during the cutting operations must be known. These deformations must therefore be measured during actual cutting. The measuring apparatus as applied to lathes, drilling machines, and milling machines, though varying greatly in individual cases, can be adapted to this research, which furnishes information on the admissible variations in deformation—which is of use during inspection—and on the forces and bending and twisting moments—which is of use to the designer. These records furnish manufacturers with the information required for organizing the sequence of operations when building machines to work with any desired precision. The “balance sheets” of various machines, giving the relationships of the forces, speeds, feeds, section of chip, power required, and efficiency, are of great value both to manufacturer and user.

Colour Doppler Spatial Resolution Performance Testing

Ultrasound ◽

10.1179/174313407x208677 ◽

2007 ◽

Vol 15 (3) ◽

pp. 162-166 ◽

Author(s):

Jacinta E Browne ◽

Ian Brown ◽

Peter R Hoskins ◽

Amanda J Watson ◽

Alex T Elliott

Keyword(s):

Spatial Resolution ◽

Performance Testing ◽

Colour Doppler ◽

Array Transducer ◽

Flow Phantom ◽

Minimum Separation ◽

Set Up ◽

Test Phantom ◽

Continuous Range

Background: Colour Doppler has become an integral part of many clinical ultrasound investigations, but evaluation of the spatial resolution of colour Doppler scanners remains problematic due to a lack of suitable test phantoms. Methods: The aims of this study were to evaluate two designs of colour Doppler spatial resolution test-phantom to compare their suitability for determining the spatial resolution of five commercially available ultrasound scanners. For the purpose of this study, spatial resolution was defined as the minimum resolvable distance between two channels of flow. Phantom 1 consisted of two diverging flow-channels. Phantom 2 consisted of four pairs of parallel channels with different separations. Results and Discussion: Both designs of phantom highlighted a number of advantages and disadvantages. In principle, phantom 1 allowed the minimal resolvable distance to be identified based on imaging a continuous range of separations, but in practice, the average separation being probed was uncertain, and the minimum separation between vessels of 1 mm was too large to test the resolutions of some of the scanners we studied. Phantom 2 was easier to set up and had a narrower minimum separation of 0.6 mm, but only four nominal separations were tested. Evaluation of five scanners using each prototype phantom suggested typical resolutions of 1·2 mm or lower. Many of the scanners possessed resolutions of approximately 0.6 mm or less, which was the minimum separation we were able to test. The poorest lateral resolution of approximately 1·2 mm was observed for a 13 year old scanner with curvilinear 4 MHz phased array transducer. Conclusion: Construction of the 'perfect' test-object for measuring colour Doppler resolution remains a considerable challenge. Further work will be required to produce acoustically realistic flow phantoms capable of testing the ability of colour Doppler to resolve increasingly narrow flow separations.

Comparative Studies of Alternative HPC Configurations for the NEWAC IRA Engine

Volume 7: Turbomachinery, Parts A, B, and C ◽

10.1115/gt2010-22052 ◽

2010 ◽

Author(s):

W. John Calvert ◽

Ed Swain ◽

Ian Woods ◽

Mark Dempsey ◽

Uwe Schmidt-Eisenlohr

Keyword(s):

Axial Compressor ◽

Flow Coefficient ◽

Engine Exhaust ◽

Radial Compressor ◽

High Pressure Compressor ◽

Core Concepts ◽

Outlet Flow ◽

Exhaust Stream ◽

Set Up

One of the core configurations being considered under the EU NEWAC (NEWAero-engine Core concepts) programme is for an intercooled recuperative aero-engine (IRA). The IRA concept exploits the heat of the engine exhaust gas and maximises the heat pick up capacity of the combustor inlet air by intercooling in front of the high pressure compressor (HPC). The datum configuration adopted for the HPC is a single stage radial compressor, but comparative design studies into alternative configurations have also been carried out. The ducting arrangements for the HPC in the IRA engine are more complicated than in a conventional turbofan engine, with the inlet flow coming from the intercooler via a C-shaped duct and the outlet flow going to the heat exchangers in the exhaust stream via 8 pipes on the outside of the engine core. A radial compressor fits quite neatly into this configuration, but the size required for a 70,000 lbf (310kN) thrust engine is significantly larger than for existing designs. In addition, the use of intercooling reduces the flow coefficient below the optimum value. By contrast, an axial compressor is likely to achieve higher efficiency, but it will be longer and have considerably more aerofoils. Therefore, preliminary designs for axial, radial and axial-CF configurations have been set up and analysed using CFD and finite element methods to assess their aerodynamic performance and to investigate their mechanical requirements. Each configuration has some advantages and disadvantages, and the results from the current studies quantify these for current levels of compressor technology.

Numerical Simulation of Intercepting Efficiency on Airbag Active Protection System

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.156-157.360 ◽

2010 ◽

Vol 156-157 ◽

pp. 360-366

Author(s):

Kun Zhong ◽

Zhong Hua Du ◽

Liang Zhou ◽

Li Li Song

Keyword(s):

Element Model ◽

Protection System ◽

Working Process ◽

3D Finite Element ◽

Active Protection ◽

New Type ◽

Simulation Results ◽

Set Up ◽

Metal Jet

Based on the advantages and disadvantages of existing active protection system, this paper proposes a new type of airbag active protection system. The components and working process of the system is introduced. Then taking the physical process of airbag active protection system against a rocket projectile as an example, a 3D finite element model (FEM) of airbag and rocket projectile is set up. With the assistance of the software LS-DYNA3D, through performing the simulation when the rocket projectile touched the airbag with an angle 30° from the normal interface, the intercepting efficiency is calculated and analyzed in the simulation. Results show that airbag can deform and rupture the metal jet generated by the rocket projectile, thus greatly reduce its armor penetrating effect. Finally, it shows excellent protective effect of the airbag active protection system.