Physical and Mechanical Properties of Some Walnut (Juglans regia L.) Cultivars

Author(s):  
Ebubekir Altuntas ◽  
Yakup Özkan

The physical properties of nuts and kernels of three Turkish walnut varieties (Juglans regia L.) such as dimensions, weight of nuts and kernels, sphericity, bulk density, volume, and coefficient of friction were determined. The resistance of the nut and kernel of walnut varieties to damage was determined by measuring the average rupture force, deformation and rupture energy along the X-, Y- and Z-axes at different compression speeds (30 and 60 mm/min). Both the static and dynamic coefficient of friction values were greater for the sheet iron surface than the galvanized one for all walnut varieties. The highest nut rupture force, deformation and rupture energy among the three walnut varieties occurred for Kaman loaded on the Y-axis. The results indicated that when testing the effects of compression axes the rupture force is highly dependent on walnut varieties. The lowest force needed to rupture the nut or kernel was found in walnut varieties with Sebin that were tested at a compression speed of 60 mm/min.

Author(s):  
I Minas ◽  
N Morris ◽  
S Theodossiades ◽  
M O’Mahony

Determining the root causes of various noise, vibration and harshness phenomena in modern automotive drivetrains is a critical task for industry, since noise, vibration and harshness issues often result in worsened driving experience. The aim of the current research is to investigate the dynamics during dry clutch engagement and the associated – often problematic – oscillations. This paper reports the development and partial validation of numerical models to study dry clutch behaviour. The models are used to investigate the influence of clutch and throttle actuation on the occurrence of unwanted clutch oscillations. The dynamic coefficient of friction between the clutch interacting surfaces was measured using a pin-on-disc rig under different slip speeds and contact pressure conditions, which are representative of a typical clutch engagement manoeuvre. The paper highlights the occurrence of instability issues in clutch dynamics (disc radial mode) as potential generators of aggressive noise, vibration and harshness, particularly during two different clutch pedal actuations. Such analysis has not hitherto been reported in the open literature.


2019 ◽  
Vol 7 (5) ◽  
pp. 311-320
Author(s):  
Umurhurhu Benjamin ◽  
Uguru Hilary

The mechanical properties of eggplant fruit (cv. Bello) harvested at physiological maturity stage were evaluated in three storage periods (3d, 6d and 9d). These mechanical parameters (rupture force, rupture energy and deformation at rupture point) were measured under quasi compression loading, using the Universal Testing Machine (Testometric model). The fruit’s toughness and rupture power were calculated from the data obtained from the rupture energy and deformation at rupture point. Results obtained showed that mechanical properties of the Bello eggplant fruit exhibited strong dependence on the storage period. The results showed that as the Bello fruit stored longer, its rupture force and rupture energy decreased from 812 N to 411 N, and 5.58 Nm to 3.11 Nm respectively. While the rupture power decreased from 1.095 W to 0.353 W. On the contrary, the toughness and deformation at rupture increased from 0.270 mJ/mm3 to 0.403 mJ/mm3, and 16.99 mm to 25.22mm respectively during the 9 days storage period. The knowledge of the mechanical properties of fruits is important for their harvest and post-harvest operations, therefore, information obtained from this study will be useful in the design and development of machines for the mechanization of eggplant production.


Author(s):  
Elchyn Aliiev ◽  
◽  
Christina Lupko ◽  

To create a database and systematize the seeds of samples of small-seeded crops, it is necessary to determine the patterns of influence of morphological parameters on their physical and mechanical properties. The development of the latest technologies and technical devices for cleaning and separation is possible due to the understanding of the characteristic morphological parameters for each of the small-seeded crops. The aim of the research is to determine the physical and mechanical properties of the seed material of small-seeded crops (mustard, flax, ryegrass, rapeseed), necessary to increase the efficiency of their cleaning and separation processes. To achieve this goal, a plan of experimental research was developed, which provided for the determination of physical and mechanical parameters of seeds of small-seeded crops, namely: indicators that characterize the flowability of seeds (angle of natural bias); frictional properties of seeds (static coefficient of friction); porosity (density) and density; size and mass characteristics of seeds (length, width, thickness, effective diameter, weight of 1000 seeds). It is established that the physical and mechanical properties of seeds of small-seeded crops are greatly influenced by its humidity. With increasing humidity, the performance of the test material increases. This is due to the fact that with increasing humidity, the shape of the seed almost turns into a spherical, which, in turn, leads to an increase in the curvature of the surface and reduce the points of contact between the seeds. As a result, the angle of natural inclination increases. The coefficient of friction of seeds of small-seeded crops depends on the roughness of the friction surface and decreases with increasing humidity. This is due to the fact that with increasing humidity decreases the forces of molecular attraction of the seed coat to the surface of the material. Seed density increases with increasing humidity. From this we can conclude that the absorption of moisture by the investigated material increases the total weight of the seed, and as a result - increases its specific weight.


2019 ◽  
Vol 14 ◽  
pp. 155892501989056
Author(s):  
Eui Kyung Roh

As a lot of time is spent in the car, the comfort of not only the car seat but also the car seat cover itself has become of increasing importance. With increasing use of ventilated seats, the control of the physical and mechanical properties of leather in response to punching has become of prime importance in the design of car seats. This study evaluated the changes in the physical and mechanical properties of leather due to punching and proposes optimum punching intervals for car seats. Sixteen types of leather, punched at three spatial intervals (2, 3, and 5 mm), were evaluated in terms of their apparent density, softness, coefficient of friction, warm-cool feeling, and mechanical properties. Leather punching affected its physical and mechanical properties. However, there were differences in punching intervals that significantly affected each property, including the mechanical properties. Depending on the performance required when developing a product, a suitable punching interval must be selected. Therefore, punching at 5 mm intervals is preferred for obtaining physical and mechanical properties similar to those of untreated leathers, and punching at 3 mm intervals is recommended for achieving more softness. On the contrary, punching at 2 mm intervals increases air permeability but decreases dimensional stability.


2013 ◽  
Vol 815 ◽  
pp. 626-631
Author(s):  
Li Xin Li ◽  
Xue Quan Liu ◽  
Cun Guang Ding ◽  
Yi Li ◽  
Fa Chang Li ◽  
...  

With the additive agent Ti3SiC2, the dry sliding behavior of Cr3C2-Ni and Cr3C2-Ni-Ti3SiC2 composites against GCr15 was investigated with a pin-on-disk tester at 400 °C in air under the load of 200N. Without Ti3SiC2, the dynamic coefficient of friction (COF) curves was fluctuated severely. After adding Ti3SiC2, the COF was decreased from 0.37 to 0.32, and the initial transition region of dynamic COF curve was shortened. These tribological test results showed that Ti3SiC2 was a new kind of solid additive agent with favorable high temperature self-lubricating property, and two possible mechanisms was proposed for its anti-friction ability.


2012 ◽  
Vol 58 (No. 3) ◽  
pp. 114-117
Author(s):  
C.F.H. Bishop ◽  
A.F.J. Gash ◽  
C. Heslim ◽  
S. Hanney

The dynamic coefficient of friction of single potatoes was determined on mild steel, rubber and plastic, for tubers in each of four conditions: dry and dirty, wet and dirty, clean and wet and clean and dry. Steel had the lowest overall mean coefficient of friction. The highest value was recorded for plastic, but this material also had the largest coefficient of variation. Overall, rubber was considered to be the most suitable all-condition material for tubers in a range of conditions.


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