Factors Affecting the Grip in Force, Shrink, and Expansion Fits

1933 ◽  
Vol 125 (1) ◽  
pp. 493-535 ◽  
Author(s):  
Robert Russell
Keyword(s):  
Metal Removal ◽  
Surface Film ◽  
Great Influence ◽  
Factors Affecting ◽  
Solid Element ◽  
Film Condition ◽  
Materials Used ◽  
Machining Operations ◽  
Shrink Fit ◽  
Motor Oils

Factors affecting the grip, which depends wholly on the elastic properties of the mating materials, are presented in the first part of the paper by a consideration of force fit practice in the assembly of wheel centres on axles. The degree of accuracy obtained in machining operations is determined by an examination of the out-of-roundness and the out-of-straightness of the cylindrical mating surfaces. The importance of considering the physical properties of the materials used in elastic grip assemblies is indicated by results obtained from specimens taken from wheel centres. Curves showing the residual force fit of elements which failed to satisfy back pressure tests suggest that failure was due to excessive fit allowances. The effect of a reduction in the surface contact area is demonstrated by a series of tests on small steel elements. The nature of the lubricant is shown to have a great effect on the force necessary to produce axial slip in a force fit assembly. The lubricants considered include rape, sperm, Bayonne and “Texaco” motor oils, a mixture of graphite and engine bearing oil, and a cutting lubricant used in metal removal operations. The influence of “skin” or film on the mating surfaces before applying the lubricant is examined in a series of tests in which the mating elements are assembled with surfaces made clean by the use of solvents and by rubbing with a clean cloth. The quality of the grip established by mating the elements, by heating the hollow element, by cooling the solid element, and by pressing the hollow element over the solid element, is considered. Experimental results show that the grip is dependent on a surface film condition which may separate the elements on assembly and may be independent of the method of assembly. The condition of the mating surfaces after the fit is broken is examined and illustrated in each case. Torsional resistance to slip is considered in the latter part of the paper. Force and shrink fit assemblies in which the elements are mated with surfaces lubricated, and with surfaces perfectly dry and free from film, are examined. An analysis of the results of tests provides further evidence of the great influence of a surface film condition on the resistance to slip and affords a means of comparing the axial and torsional coefficients of friction.

scholarly journals Application of immobilized mycelium-based pellets for the removal of organochlorine compounds: a review

2021 ◽  
Author(s):  
J. C. V. Pereira ◽  
M. P. Serbent ◽  
E. Skoronski
Keyword(s):  
Wastewater Treatment Plants ◽  
Cost Effective ◽  
Field Studies ◽  
Organochlorine Compounds ◽  
Environmental Persistence ◽  
Factors Affecting ◽  
Materials Used ◽  
Immobilization Techniques ◽  
Enzymatic Machinery

Abstract Organochlorines have diverse structures and applications and are included in the list of persistent organic pollutants (POPs) due to their toxicity and environmental persistence. The reduced capacity of conventional wastewater treatment plants to remove these compounds encourages the development of cost-effective and efficient remediation approaches. Fungal biotechnology can contribute to the development of these technologies through their enzymatic machinery but faces several drawbacks related to the use of dispersed mycelium. In this sense, investigations concerning the degradation of organochlorines using immobilized fungi demonstrated an increase in contaminants removal efficiency compared with degradation by free cells. Despite this interest, the mechanisms of immobilized fungi have not been comprehensively reviewed. In this paper, recent advances of laboratory and field studies in organochlorine compounds removal by fungi were reviewed, focusing on the role of immobilization techniques. Firstly, the mechanisms of organochlorines bioconversion by fungi and the factors affecting enzyme activity are elucidated and discussed in detail. Then, the main targeted compounds, fungi, technics, and materials used for immobilization are discussed, as well as their advantages and limitations. Furthermore, critical points for future studies of the fungi immobilization for organochlorines removal are proposed.

Assessing Low-Cost Housing Demand in Melaka: PLS-SEM Approach

2013 ◽  
Vol 838-841 ◽  
pp. 3156-3162 ◽  
Author(s):  
Noor Yasmin Zainun ◽  
Nadzirah Roslan ◽  
Aftab Hameed Memon
Keyword(s):  
Low Income ◽  
Goodness Of Fit ◽  
Housing Stock ◽  
Low Cost ◽  
Great Influence ◽  
Economic Factor ◽  
Housing Demand ◽  
Factors Affecting ◽  
Low Cost Housing ◽  
The Government

Housing is one of the basic needs of human. Population in Malaysia is increasing and expected to reach up to 35 million in year 2020. This phenomenon creates high demand for housing. To tackle the squatter problems, the government introduces low-cost housing. Low cost house is known as the government house, where the price is cheaper but still comfortable. Although there are many of low-cost housing projects have been completed to cope with the need of the citizen especially for low-income group. However, census report reveled that these is huge demand of low-cost housing. This demand might be because of various factors which are very essential to identify in order to meet the required demand of low cost houses. Hence, this study is carried out to assesse the demand of low cost housing in Melaka, determine the significant factors affecting demand of low-cost housing, and establish PLS-SEM model for assessing factors affecting low-cost housing demand. In this study, data are collected by distributing questionnaire in Melaka state. The collected data from survey was analyzed using statistical software SPSS and presented in graphs and chart. Further, factors affecting low cost housing demand in Melaka were modeled with the SmartPLS v2.0. The model shows the relationship between low cost housing demand and its indicators. The finding of the study showed that most significant indicators affecting the demand of low-cost housing in Melaka are the economic factors which include housing stock, inflation rate and Gross Domestic Products (GDP). The Goodness of Fit showed that the model has substantial explaining power for the assessing factors affecting low cost housing demand in Melaka which the values is 0.481. This means that the economic factor has a great influence on the low-cost housing demand in Melaka.

scholarly journals Factors Affecting the Thermal Insulation and Abrasion Resistance of Heat Resistant Hydro-Entangled Nonwoven Batting Materials for Use in Firefighter Turnout Suit Thermal Liner Systems

2011 ◽  
Vol 6 (1) ◽  
pp. 155892501100600 ◽  
Author(s):  
Roger L. Barker ◽  
Ryan C Heniford
Keyword(s):  
Thermal Insulation ◽  
Abrasion Resistance ◽  
Aramid Fibers ◽  
Thermal Protective Performance ◽  
Factors Affecting ◽  
Fiber Composition ◽  
Heat Resistant ◽  
Materials Used ◽  
Protective Performance

This paper describes a study on heat resistant nonwoven batting materials used as components in the construction of thermal liners systems in firefighter turnout suits. It examines relationships between the fiber composition and construction of hydroentangled nonwoven battings and properties that can affect their performance when used in this application. Relationships between batting porosity, weight, thermal insulation, bulk and abrasion resistance are examined in hydroentangled constructions made with oxidized PAN, para-aramid and meta-aramid fibers. Correlations observed between the insulation of batting materials components and the thermal protective performance of integrated multilayered fabric systems used in firefighter turnout suits are described.

Mechanism of Rubber Cracking

1946 ◽  
Vol 19 (2) ◽  
pp. 406-416 ◽  
Author(s):  
E. F. Powell ◽  
V. E. Gough
Keyword(s):  
Laboratory Tests ◽  
Surface Film ◽  
Factors Affecting ◽  
Laboratory Conditions ◽  
Service Conditions ◽  
Exposure Conditions

Abstract Rubber and rubberlike polymers, in common with other materials which deteriorate on exposure to oxidizing or similar agents, eventually crack under normal atmospheric service conditions. The present paper confines itself to the factors affecting the type and appearance of the cracking which eventually occurs when a surface film of a rubber object (particularly when stressed) hardens and deteriorates in strength from any cause whatsoever. The importance of an understanding of the effects of exposure conditions on the character of the cracking produced cannot be too highly emphasized. This is so even if interest is confined solely to simple tests on new protective paints on an acceptance basis rather than research into surface deterioration. It is probable that many protective agencies have been accepted or rejected for extensive production tests because the initial laboratory tests have either not been representative of service or have been inadequate in scope. This still remains a major problem. The theory presented here has gradually taken shape over a period of some ten years and appears to describe adequately the general findings on the whole gamut of cracking, viz., fine check cracking and isolated deep cracks produced under service and laboratory conditions, the latter covering flexing, roof exposure, ozone and similar tests.

Remote Sensing Monitoring and Analysis on Land Utilization Status on Aksu River Basin of Xinjiang Uygur Autonomous Region

2011 ◽  
Vol 282-283 ◽  
pp. 177-180
Author(s):  
Bai Lian Lai
Keyword(s):  
Remote Sensing ◽  
River Basin ◽  
Great Influence ◽  
Land Development ◽  
Tarim River ◽  
Tarim River Basin ◽  
Land Utilization ◽  
Factors Affecting ◽  
Remote Sensing Monitoring ◽  
The Tarim River Basin

Aksu river is one of the biggest branches in the Tarim river basin, where the land utilization and its changes have great influence on the water supply in the lower reaches, and they are also the main factors affecting its ecological restoration. This paper, with the help of three-level intermediate resolution and remote sensor, carries out the remote sensing monitoring and analysis on its land utilization, analyses the changes of farmland and construction land, and provides basis for the planning of land development and the comprehensive assessment for the ecological environment.

Enhanced Thermal Conductivity for Graphene Nanoplatelets/Epoxy Resin Composites

2017 ◽  
Vol 10 (1) ◽  
Author(s):  
Dahai Zhu ◽  
Yu Qi ◽  
Wei Yu ◽  
Lifei Chen ◽  
Mingzhu Wang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Epoxy Resin ◽  
Mass Fraction ◽  
Great Influence ◽  
Graphene Nanoplatelets ◽  
Resin Matrix ◽  
Heat Conducting ◽  
Factors Affecting ◽  
Molding Method ◽  
Ep Matrix

Graphene nanoplatelets (GNPs) have excellent thermal conductivity. It can significantly improve the heat-conducting property of epoxy resin (EP) matrix. In this paper, the GNPs/EP composites were successfully prepared by using ultrasonication and the cast molding method. The prepared GNPs/EP composites were systematically characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermal conductivity analyzer. Some factors affecting the thermal transfer performance of the composites were discussed. The defoamation has great influence on the thermal conductivity of composite. There is a nearly linear relationship between the mass fraction and the thermal conductivity of composite when the mass fraction of GNPs is below 4.3%. The results show that when the mass fraction of GNPs is 4.3% with crushing time of 2 s, the thermal conductivity of GNPs/EP composite is up to 0.99 W/m K. The thermal conductivity is increased by 9.0% compared with that without pulverization treatment (0.91 W/m K). When it is ground three times, the thermal conductivity of composite reaches the maximum (1.06 W/m K) and it is increased by 307.7% compared with that of epoxy resin matrix.

scholarly journals Modeling of geometry and insertion force of a new lancet medical needle

2019 ◽  
Vol 103 (1) ◽  
pp. 003685041989107
Author(s):  
Yingchun Qi ◽  
Jingfu Jin ◽  
Tingkun Chen ◽  
Qian Cong
Keyword(s):  
Great Influence ◽  
Large Change ◽  
Processing Parameters ◽  
Needle Insertion ◽  
Grinding Wheel ◽  
Insertion Force ◽  
Factors Affecting ◽  
Organ Tissue ◽  
Needle Insertion Force ◽  
The Relationship

Lancet needle is a typical medical treatment device. Its tip consists of two lancet planes and one bevel plane. When the lancet needle is inserted into soft organ tissue, the insertion force may influence the needle cutting direction and treatment effect and increase the pain. One of the main factors affecting this insertion force is the geometry of the needle tip. Based on the research on the shape and processing method of the conventional lancet needle, a new lancet needle tip geometry was obtained by adjusting the relative position of the grinding wheel to the needle. A mathematical model of this new lancet needle was established. The relationship between processing parameters and needle shape was analyzed, and the needle insertion force was predicted. Compared with the conventional lancet needle, the new lancet needle is sharper, and the insertion force on the cutting edge is smaller. However, this change in the grinding position of the needle lancet plane has a great influence on the shape of needle tip near the intersection of the bevel plane and the lancet plane. Some special second bevel angle and rotated angle will cause a large change in the specific force at the intersection place, which is not conducive to reducing the insertion force.

Experimental Investigation of Vibratory Finishing Process

2014 ◽  
Author(s):  
Xiaozhong Song ◽  
Rahul Chaudhari ◽  
Fukuo Hashimoto
Keyword(s):  
Surface Roughness ◽  
Experimental Investigation ◽  
Metal Removal ◽  
Contact Forces ◽  
Chemical Solution ◽  
Impact Frequency ◽  
Vibratory Finishing ◽  
Factors Affecting ◽  
Finishing Process ◽  
Chemical Solutions

The vibratory finishing process is widely used for finishing metal components. An experimental investigation is reported on the factors affecting the metal removal and resultant surface roughness during vibratory finishing including the influence of chemical solutions. The effect of process parameters such as media size and impact frequency is studied by measuring the contact forces. A method to investigate the effect of chemical solution and to optimize the processing time to achieve desired resultant surface roughness is presented.

DETERMINANTS OF THE SELECTION OF RAW MATERIALS USED IN ANIMAL FEED PRODUCTION

2020 ◽  
Vol XXII (2) ◽  
pp. 191-199
Author(s):  
Magdalena Śmiglak-Krajewska
Keyword(s):  
Animal Feed ◽  
Raw Materials ◽  
Soya Bean ◽  
Raw Material ◽  
Factors Affecting ◽  
Feed Production ◽  
Bean Meal ◽  
Materials Used ◽  
Soya Bean Meal ◽  
Selection Of

The main purpose of this paper was to identify the factors affecting the selection of raw materials used by feed operators in feed production. An attempt was also made to indicate the barriers to increasing the use of native protein plants by feed operators in feed production. Today, many EU countries (including Poland) primarily rely on vegetable protein derived from genetically modified soya bean meal (mainly imported from South America and the U.S.) in addressing their needs for protein raw material used in animal feed. For many years now, Poland has taken steps to increase the production and use of native protein raw material to partially replace soya bean meal imports. The use of mixes of diverse domestic protein sources derived from grain legumes (peas, field beans, lupine) can provide an advantageous alternative to compound feeding stuff based on imported post-extraction soya bean meal. To meet the objective defined above, this paper relied on the results of a 2018 survey conducted with a sample of 29 feed operators located across the country. More than half (55%) of the enterprises surveyed did not use legumes in feed production; the use of legumes was above 10% in only 3% of respondents. When asked about the key factors affecting the selection of raw materials used in production processes, the respondents declared to be interested in buying large batches of homogeneous raw materials that meet specific quality parameters (33% replied “rather yes” and 67% replied “definitely yes”). The protein content of plant seeds used in feed production was identified as another aspect of extreme importance (55% replied “rather yes” and 24% replied “definitely yes”).

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