Reliability Design and Wear Extent Determination of a Cam Mechanism

2012 ◽  
Vol 268-270 ◽  
pp. 1034-1038
Author(s):  
Yi Yuan Ge ◽  
Jun Fa Wang ◽  
Gui Lian Wang ◽  
Ya Qin Li
Keyword(s):  
Fuzzy Optimization ◽  
Reliability Design ◽  
Cam Mechanism ◽  
Before And After ◽  
Base Circle ◽  
Important Field ◽  
Conventional Optimization ◽  
Maximum Contact ◽  
Mechanical Movement

The application of the cam mechanism is an important field in agricultural machinery since it can realize complex mechanical movement. The wear extent and action reliability of the cam affect the performance and accuracy of the mechanism. The paper combined reliability optimal design and tribology to build a fuzzy optimization model, with minimum of the cam base circle radius and minimum of the maximum contact stress as the objective functions. Compared with conventional optimization, the cam weight was reduced by 11.7%, the stress was increased by 1.96%, and the reliability increased 0.71%. Contrast tests were designed to determine the wear extent before and after optimization. The results prove the feasibility of optimization.

scholarly journals Determination of soil density by theoretical and experimental methods

2021 ◽  
Vol 344 (1) ◽  
pp. 60-63
Author(s):  
A. V. Lavrov ◽  
M. A. Litvinov
Keyword(s):  
Soil Moisture ◽  
Harmful Effect ◽  
Soil Density ◽  
Steel Cylinder ◽  
Soil Hardness ◽  
Three Samples ◽  
Before And After ◽  
Almost All ◽  
Maximum Contact

Relevance. According our researches it was found that almost all models oftractors and self-propelled machines has created the maximum contact pressure ofthe movers on the soil above the permissible values. In such way, in view ofthe extreme topicality of the saving soil fertility during evaluating theagrotechnical indicators of a self-propelled selection seeder, it is necessary, first ofall, to make researches to determine the harmful effect of propellers on the soil.Methods. Theoretical researches of determining the soil hardness and density werecarried out using the dependence of density on hardness. During the tests of theself-propelled selection seeder, soil moisture was measured at a depth of 3 inches (7.6 cm) and it was 20%. To measure soil moisture, It was used a digital device, itwas a universal moisture meter TK100. Samples were taken before and after eachpass of the self-propelled seeder with the front and rear wheels. Hardness wasmeasured for each sample.The Kachinskys method was used to measure soil density as the experimentalmethod. To take soil samples, a 100 cubic meter drill (steel cylinder) was used.Soil samples were taken according to the method described above. At the sametime, for each case, three samples were taken to exclude random deviations in soildensity indicators. In the laboratory, the samples were weighed on a VK 3000.1electronic balance with a measurement error of 0.1 grams.Results. The soil density was determined by calculation and experimental methodsin three zones: before the seeder pass and after each its pass in the track behind thefront and rear wheels at a depth of 7.6 cm. The results obtained differ from eachother by a maximum of 6.2%.

The Plasmin Inhibitors of Plasma

1964 ◽  
Vol 12 (01) ◽  
pp. 119-125 ◽  
Author(s):  
Y Shamash ◽  
A Rimon
Keyword(s):  
Human Plasma ◽  
New Method ◽  
Normal Amount ◽  
Caseinolytic Activity ◽  
Before And After ◽  
Plasmin Inhibitors

SummaryA new method for the assay of plasmin inhibitors in human plasma is described. The method consists of determination of the caseinolytic activity of a standard plasmin solution before and after incubation with the inhibitor, with lysine added to the mixture as a stabilizer of plasmin. Using this method, it was found that plasma contains enough inhibitors to inactivate 30 caseinolytic units of plasmin, or 10 times the normal amount of plasminogen in human plasma.

FRACTIONAL DETERMINATIONS OF URINARY 17-KETOSTEROIDS IN HYPEREMESIS GRAVIDARUM

1962 ◽  
Vol 41 (1) ◽  
pp. 123-128 ◽  
Author(s):  
Pentti A. Järvinen ◽  
Sykkö Pesonen ◽  
Pirkko Väänänen
Keyword(s):  
Hyperemesis Gravidarum ◽  
First Trimester ◽  
Control Group ◽  
Before And After ◽  
Daily Urine ◽  
First Trimester Of Pregnancy ◽  
The Difference

ABSTRACT The fractional determination of 17-ketosteroids in the daily urine was performed in nine cases of hyperemesis gravidarum and in four control cases, in the first trimester of pregnancy both before and after corticotrophin administration. The excretion of total 17-KS is similar in the two groups. Only in the hyperemesis group does the excretion of total 17-KS increase significantly after corticotrophin administration. The fractional determination reveals no difference between the two groups of patients with regard to the values of the fractions U (unidentified 17-KS), A (androsterone) and Rest (11-oxygenated 17-KS). The excretion of dehydroepiandrosterone is significantly higher in the hyperemesis group than in the control group. The excretion of androstanolone seems to be lower in the hyperemesis group than in the control group, but the difference is not statistically significant. The differences in the correlation between dehydroepiandrosterone and androstanolone in the two groups is significant. The high excretion of dehydroepiandrosterone and low excretion of androstanolone in cases of hyperemesis gravidarum is a sign of adrenal dysfunction.

DETERMINATION OF BLOOD CORTICOIDS USING THE IN VITRO RESIN UPTAKE OF 3H-PREDNISOLONE

1968 ◽  
Vol 57 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Hironori Nakajima ◽  
Mitsunori Murala ◽  
Masumitsu Nakata ◽  
Takeshi Naruse ◽  
Seiji Kubo
Keyword(s):  
Thyroid Function Test ◽  
Normal Subjects ◽  
Adrenal Function ◽  
Function Test ◽  
Before And After ◽  
Adrenal Response ◽  
Suppression Test

ABSTRACT The in vitro resin uptake of 3H-prednisolone was used for the determination of blood cortisol after addition of radioactive prednisolone followed by Amberlite CG 400 Type 1 to the test serum, and incubation of the mixture. The radioactivity of the supernatant was compared before and after the addition of the resin. The principle of this method is similar to that of the 131I-triiodothyronine resin uptake for the thyroid function test. The tests for the specificity, reproducibility and sensitivity gave satisfactory results. The mean basal value ± SD of the 3H-prednisolone resin uptake was 35.3 ± 9.2% in normal subjects, and 27.1 ± 4.8% in pregnant women. This method was valid in various adrenal function tests, i. e. the adrenal circadian rhythm, corticotrophin (ACTH) test, dexamethasone suppression test and the adrenal response to lysine-8-vasopressin. It proved to be a sensitive indicator of the adrenal function. These results suggest that this method should be useful for a routine adrenal function test.

Thermal Elastohydrodynamic Lubrication of an Optimized Cam–Tappet Pair in Smooth Contact

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
W. Wu ◽  
J. Wang ◽  
C. H. Venner
Keyword(s):  
Film Thickness ◽  
Elastohydrodynamic Lubrication ◽  
Temperature Profiles ◽  
Cam Mechanism ◽  
Basic Segment ◽  
Order Polynomial ◽  
Isothermal Analysis ◽  
Base Circle ◽  
Smooth Contact ◽  
Oil Characteristics

A high-order polynomial gas distribution cam mechanism is investigated theoretically from the viewpoint of thermal elastohydrodynamic lubrication (EHL). First, a cam with a larger base circle radius is employed, which results in slide–roll ratio 2.0 < S < 9.0 when the two surfaces move oppositely. The pressure, film thickness, and temperature profiles at a number of angular positions of the cam are presented, together with the isothermal results. The comparison between thermal and isothermal oil characteristics is also shown. It is revealed that the isothermal analysis partly overestimates the actual film thickness and it also misses some essential local phenomena. Second, a cam with a smaller base circle radius is studied, which leads to drastic variations in the slide–roll ratio which encounters four times’ occurrences of infinity in one working period. The pressure, film thickness, and temperature profiles at some angular cam positions together with the oil characteristics are given, showing much dramatic variations. A very small film thickness is observed at the contact of the tappet with the start of the cam basic segment, which suggests a possible risk of direct contact of both surfaces.

Method for the simultaneous quantification of n-hexane metabolites: application to n-hexane metabolism determination

1996 ◽  
Vol 15 (6) ◽  
pp. 497-503 ◽  
Author(s):  
T. Soriano ◽  
M. Menéndez ◽  
P. Sanz ◽  
M. Repetto
Keyword(s):  
Similar Pattern ◽  
Analytical Procedure ◽  
Daily Basis ◽  
Practical Application ◽  
Simultaneous Quantification ◽  
Exposed Workers ◽  
Before And After ◽  
Time Requirements ◽  
The Difference

1 The described analytical procedure permits the simultaneous determination of the main n-hexane meta bolites in urine. 2-Hexanone, 2-hexanol, 2, 5-hexanediol and 2, 5-hexanedione, were chosen to dose the rats used in this study. All urine samples were collected and analysed on a daily basis, before and after acidic hydrolysis (pH 0.1) by GC/MS. 2-Hexanone, 2, 5-dimethylfurane, γ-valerolac tone and 2, 5-hexanedione were determined before hydro lysis ; 2-hexanol and 2, 5-hexanediol, after hydrolysis; and 5-hydroxy-2-hexanone and 4, 5-dihydroxy-2-hexanone were calculated by the difference between γ-valerolactone and 2, 5-hexanedione with and without hydrolysis, respectively. 2 A metabolic scheme was proposed reflecting the biotransformations undergone by the four compounds assayed. We consider 2, 5-dimethylfurane as a 'true metabolite' because the quantities detected were always greater before hydrolysis. 3 It has been reported that human and rat n-hexane metabolism follow a similar pattern. Therefore, as a practical application and without increasing either sample or time requirements, the simultaneous quantifi cation of the different metabolites and their excretion profile could provide better information about the metabolic situation of exposed workers than the determi nation of 2, 5-hexanedione alone. According to our experimental results, 4, 5-dihydroxy-2-hexanone itself would be a good toxicity indicator.

Effect of induced metabolic acidosis on intracellular pH, buffer capacity and contraction force of human skeletal muscle

1985 ◽  
Vol 69 (5) ◽  
pp. 505-510 ◽  
Author(s):  
E. Hultman ◽  
S. Del Canale ◽  
H. Sjöholm
Keyword(s):  
Buffer Capacity ◽  
Recovery Period ◽  
Mean Values ◽  
Muscle Ph ◽  
Before And After ◽  
Ph Buffer ◽  
Total Capacity ◽  
Ph Decrease ◽  
Muscle Biopsies

1. Five volunteers were studied before and after oral administration of NH4Cl (0.3 g/kg body wt.) given in order to create a moderate acidosis. 2. The quadriceps femoris muscles were stimulated electrically for 75 s and muscle biopsies for determination of pH and metabolite content were taken before, at the end of contraction and after 10 min in the recovery period. 3. Muscle pH at rest (mean 7.04) was not significantly decreased after acidification despite an extracellular pH decrease of 0.15 unit. 4. After contraction muscle pH was significantly lower after NH4Cl. Mean values before and after acidification were 6.70 and 6.54 respectively. 5. The buffer capacity calculated as the total capacity of the muscle to buffer H+ produced during the isometric contraction before and after NH4Cl ingestion was reduced from 68.6 sl to 54.5 sl. 6. The force produced by contracting muscle was significantly lower at the end of the contraction period after NH4Cl ingestion, 44.6% of initial compared with 55.4% without NH4Cl.

Testing of the usability of the C-band Electronic Corner Reflector (ECR-C) in Hungary based on Sentinel-1 SAR data

2021 ◽  
Author(s):  
Roland Horvath ◽  
Sandor Toth ◽  
Balint Magyar
Keyword(s):  
Satellite System ◽  
Radar Signal ◽  
Reference Network ◽  
Interferometric Synthetic Aperture Radar ◽  
Corner Reflector ◽  
Pixel Intensity ◽  
Persistent Scatterer ◽  
Before And After ◽  
Geodetic Application

&lt;p&gt;The key infrastructural elements of the geodetic application of the Interferometric Synthetic Aperture Radar (InSAR) are the integrated benchmarks which are satellite technologies, besides the traditional geodetic technologies, therefore they serve as benchmarks of the Global National Satellite System (GNSS) and InSAR.&lt;/p&gt;&lt;p&gt;Previously, the Satellite Geodetic Observatory (SGO) has already built a network of the passive corner reflectors (SENGA) near the Hungarian GPS Geokinematic Reference Network. This infrastructure is added by an active corner reflector (called transponder) which is the first device according to our knowledge in Hungary. We have been testing the transponder in recent months. The scope of our work is the detection of the intensity of the emitted radar signal by the Sentinel-1 C-band satellite VV polarisation sensor using GAMMA Remote Sensing Software with 6 day repeat cycle availability of satellite images in ascending and descending passes. Hence, we could monitor and compare of the pixel-intensity (expressed in decibel) before and after the installation. The value of the pixel is increased around 15-20 dB and we had chance to set the Radar Cross Section (RCS=31 dBm2) against the results of existing researches. &lt;span&gt;During the testing period the ECR was placed on the roof&lt;/span&gt;&lt;span&gt;top of the &lt;/span&gt;&lt;span&gt;S&lt;/span&gt;&lt;span&gt;GO, but in &lt;/span&gt;&lt;span&gt;the short&lt;/span&gt;&lt;span&gt;-term the design &lt;/span&gt;&lt;span&gt;of the relocation of the device as InSAR Persistent Scatterer&lt;/span&gt; &lt;span&gt;has also been developed&lt;/span&gt;&lt;span&gt;.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;One of the goals of our research is the incorporation of the transponders into the SENGA network which is needed to be expanded, examination and determination of the conditions of this integration.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

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