scholarly journals The Effect of Wheat Moisture and Hardness on the Parameters of the Peleg and Normand Model during Relaxation of Single Kernels at Variable Initial Loading

2019 ◽  
Vol 11 (24) ◽  
pp. 7100
Author(s):  
Jawad Kadhim Al Aridhee ◽  
Grzegorz Łysiak ◽  
Ryszard Kulig ◽  
Monika Wójcik ◽  
Marian Panasiewicz
Keyword(s):  
Testing Machine ◽  
Load Level ◽  
Elastic Behavior ◽  
Wheat Varieties ◽  
Wheat Kernel ◽  
Initial Loading ◽  
Force Decay ◽  
Relaxation Experiments ◽  
Initial Force ◽  
Recoverable Energy

The aim of the study was to examine the Peleg and Normand model to characterize the overall stress relaxation behavior of wheat kernel at varying load conditions. The relaxation experiments were made with the help of the universal testing machine, Zwick Z020, by subjecting the samples to compression at four distinct initial load levels, i.e., 20 N, 30 N, 40 N, and 50 N. The measurements were made for four wheat varieties (two soft and two hard-type endosperms) and seven levels of moisture content. Relaxation characteristics were approximated with the help of the Peleg and Normand equation. An interactive influence of the load level, moisture, and wheat hardness on the Peleg and Normand constants has been confirmed. For moist kernels, a higher amount of absorbed compression energy was released, since less energy was required to keep the deformation at a constant level. The constants differed depending on wheat hardness. Higher values of k1 revealed that the initial force decay was slower for hard varieties. This is more characteristic of elastic behavior. Similarly, higher values of k2 pointed to a larger amount of elastic (recoverable) energy at the end of the relaxation. The initial loading level had no or only a slight effect on the model coefficients (Y(t), k1, and k2). The parameters of the Peleg and Normand model decreased with an increase in the water content in the kernels.

scholarly journals An in vitro comparison of the force decay generated by different commercially available elastomeric chains and NiTi closed coil springs

2007 ◽  
Vol 21 (1) ◽  
pp. 51-57 ◽  
Author(s):  
Ana Cristina Soares Santos ◽  
André Tortamano ◽  
Sandra Regina Frazatto Naccarato ◽  
Gladys Cristina Dominguez-Rodriguez ◽  
Julio Wilson Vigorito
Keyword(s):  
Artificial Saliva ◽  
Testing Machine ◽  
In Vitro Study ◽  
Original Length ◽  
Force Decay ◽  
Decay Pattern ◽  
The Mean ◽  
Initial Force ◽  
Elastomeric Chains

This in vitro study was designed to compare the forces generated by commercially available elastomeric chains and NiTi closed coil springs, and to determine their force decay pattern. Forty elastomeric chains and forty NiTi closed coil springs were divided into 4 groups according to the following manufacturers: (1) Morelli®, (2) Abzil®, (3) TP Orthodontics® and (4) American Orthodontics®. The specimens were extended to twice their original length and stored in artificial saliva at 37°C. Initial force was measured by means of an Instron universal testing machine and then at 1, 4, 7, 14, 21, and 28 days. The results revealed that the elastomeric chains delivered a mean initial force of 347 g for Morelli®, 351 g for American Orthodontics®, 402 g for Abzil®, and 404 g for TP Orthodontics®. The NiTi closed coil springs generated a mean initial force of 196 g for American Orthodontics®, 208 g for TP Orthodontics®, 216 g for Abzil®, and 223 g for Morelli®. The mean percentage of force decay observed after 28 days for the elastomeric chains was 37.4% for TP Orthodontics®, 48.1% for American Orthodontics®, 65.4% for Morelli®, and 71.6% for Abzil®. After 28 days, the NiTi closed coil springs presented a mean percentage of force decay of 22.6% for American Orthodontics®, 29.8% for Abzil®, 30.6% for Morelli®, and 45.8% for TP Orthodontics®. At the end of the study, significant differences were observed between the elastomeric chains and the NiTi closed coil springs. The results indicated that the studied NiTi closed coil springs are more adequate for dental movement than the elastomeric chains.

scholarly journals Verification of the Peleg and Normand Equation at Varied Loads and Moisture During Stress Relaxation of Wheat

2019 ◽  
Vol 23 (3) ◽  
pp. 89-99
Author(s):  
Grzegorz Łysiak ◽  
Ryszard Kulig ◽  
Monika Wójcik
Keyword(s):  
Stress Relaxation ◽  
Strain Energy ◽  
Load Level ◽  
Slight Effect ◽  
Universal Machine ◽  
Wheat Kernel ◽  
Initial Load ◽  
Relaxation Experiments ◽  
Wheat Kernels ◽  
Relaxation Characteristics

AbstractWheat kernel is made up of structures of different apparent viscosities with varied ability to withstand stress and dissipate strain energy. Its complex mechanical behaviour determines technological susceptibility and is important for wheat quality assessment. The aim of the study was the examination of the Peleg and Normand model to characterize the overall stress relaxation behaviour of wheat kernel at varying loading conditions. The relaxation experiments were made with a help of a universal machine Zwick Z020 in compression at four distinct initial load levels, i.e., 20, 30, 40, and 50 N. The measurements were made for intact wheat kernels at seven levels of moisture content. Relaxation characteristics were approximated with the help of Peleg and Normand formula. An interactive influence of the load level and moisture on Peleg and Normand constants have been confirmed. The initial loading level had none or only slight effect on the model coefficients (Y(t), k1 and k2). The parameters of the Peleg and Normand model decreased with the increase of water content in kernels. For moist kernels, a higher amount of absorbed compression energy was relaxed, since less energy was necessary to keep the deformation at a constant level.

Design of High Frequency Fatigue Testing Machine Driven by Piezoelectric Vibrator

2012 ◽  
Vol 220-223 ◽  
pp. 543-548
Author(s):  
Meng Jie ◽  
Hai Feng Xie ◽  
Yan Liu ◽  
Zhi Gang Yang
Keyword(s):  
High Frequency ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Fatigue Property ◽  
Maximum Load ◽  
Load Level ◽  
Piezoelectric Resonance ◽  
Piezoelectric Vibrator ◽  
Plate Spring ◽  
Working Principle

In order to measure the fatigue property of the small and hard brittle components working under conditions of the little amplitude, high frequency force, a novel kind of resonant high frequency fatigue testing machine which is driven by the piezoelectric vibrator (PZT、PLZT or PMN) has been proposed. Firstly, the working principle of the piezoelectric resonance high frequency fatigue testing machine is analyzed, and the dynamic model of the fatigue testing machine is established to get the systemic dynamic characteristics. Then a prototype is designed and produced. Finally, the maximum load on the sample is measured by the test with the machine. The results indicate that the maximum load on the sample is 23.4N-98.1N when changing the voltage (100V-250V) and the thickness of the plate spring (1.1mm-0.6mm). The prototype made in this paper is suitable for the tensile and fatigue testing with the load level mentioned above under the condition of little amplitude and high frequency force.

scholarly journals The B Group Vitamins and Mineral Elements in the Selective Removal of Wheat Kernel Layers

2006 ◽  
Vol 1 (11) ◽  
pp. 1934578X0600101 ◽  
Author(s):  
Biljana V. Vucelic-Radovic ◽  
Vjaceslav M. Nesic ◽  
Mirjana A. Demin ◽  
Mirjana M. Milovanovic
Keyword(s):  
Nutritive Value ◽  
Pantothenic Acid ◽  
Mineral Elements ◽  
Selective Removal ◽  
Wheat Varieties ◽  
Wheat Grains ◽  
Wheat Kernel ◽  
Whole Wheat ◽  
Distribution Of Elements ◽  
Soft Winter Wheat

The objective of this study was to investigate how selective removal of the surface layers of whole wheat grains by abrasive scouring affects the distribution of mineral elements (macronutrients, micronutrients and trace elements) and the B group vitamins (thiamin, riboflavin pyridoxine, pantothenic acid and niacin) in three soft winter wheat varieties (Partizanka, Novosadska rana and Lasta). Although representing technologically different quality classes of wheat, the varieties were not significantly different in the B group vitamin contents, except for pyridoxine. Whole grains of all varieties exhibited very similar scouring behavior in reduction of vitamins: the most intensive investigated regime only slightly, but not significantly reduced the concentration of the B group vitamins. The nutritive value of scoured wheat grains with regard to the B group vitamins was preserved. The investigated minerals were: Na, K, Ca, Mg, Mn, Fe, Cu, Zn, Ni, Cr, Se, Pb and Cd. The concentrations of minerals in scoured wheat grains were significantly reduced, dropping on average to 65% of the initial values for macro and 55% for microelements. The change of concentrations with the duration of applied treatment followed different patterns for different elements. Furthermore, a different pattern of the change for the same element in different wheat varieties was noticed. This might be due either to different mechanical properties of bran and bran layer interfaces or genotypic variability in distribution of elements in wheat grain. Severe reduction in Pb concentrations was achieved leading to improvement of whole-wheat food safety.

Biomechanical Evaluation of a Four-Strand Modification of the Tang Method of Tendon Repair

2005 ◽  
Vol 30 (4) ◽  
pp. 374-378 ◽  
Author(s):  
Y. CAO ◽  
J. B. TANG
Keyword(s):  
Ultimate Strength ◽  
Testing Machine ◽  
Tendon Repair ◽  
Gap Formation ◽  
Single Cycle ◽  
Tensile Testing Machine ◽  
Load To Failure ◽  
Biomechanical Evaluation ◽  
Finger Motion ◽  
Initial Force

We report a four-strand modification of the Tang technique of tendon repair that uses fewer sutures and fewer knots on the tendon surface. This repair consists of four longitudinal and two horizontal strands that form a “U” configuration within the tendon made with a single looped suture. Thirty-four fresh pig flexor tendons were divided into 3 groups and repaired with the four-strand modified Tang method, a double-looped four-strand method or a double Kessler repair (four-strand). The tendons were subjected to a single cycle of load-to-failure test in a tensile testing machine. The initial force, 2-mm gap formation force and ultimate strength of the four-strand modified Tang repair were statistically identical to those of the double looped suture and were superior to those of the double Kessler repair. Ultimate strength was 43.4 ± 4.3 N for the four-strand modified Tang method, 45.2 ± 4.0 N for the double-looped method and 39.1 ± 4.0 N for the double Kessler repair. The four-strand modification of the Tang method appears to have strength sufficient for protected active finger motion. Given our preliminary clinical experience with this method, we recommend this new and simplified technique for clinical flexor tendon repairs.

scholarly journals Comparative evaluation of force decay pattern in orthodontic active tiebacks exposed to five different mouth rinses: An in vitro Study

2020 ◽  
Vol 14 (4) ◽  
pp. 244-249
Author(s):  
Amir Hossein Mirhashemi ◽  
Atefe Saffar Shahroudi ◽  
Keyvan Shahpoorzadeh ◽  
Niloofar Habibi Khameneh
Keyword(s):  
In Vitro Study ◽  
Vitro Study ◽  
Control Group ◽  
Mouth Rinses ◽  
Force Decay ◽  
Force Relaxation ◽  
Decay Pattern ◽  
Initial Force ◽  
And Control

Background. This study compared the force decay pattern of two different orthodontic active tiebacks (ATBs) exposed to five different commercially available mouth rinses. Methods. In this in vitro study, 90 transparent ATBs and 90 gray ATBs were divided into six groups; one was the control group, and the others were exposed to one of these mouth rinses twice a day for 60 seconds: Listerine, chlorhexidine, Orthokin, Persica, and fluoride. The initial force of each ATB was 250 g at a 24-mm extension. The force of ATBs was measured on days 1, 7, 14, and 28 using a digital gauge. Results. The highest percentage of force loss was observed between days 14 and 28 (P<0.05). At the end of the study, the Persica group exhibited the highest force degradation in both ATB types. In the transparent ATBs, it was followed by Orthokin, Listerine, fluoride, chlorhexidine, and control groups, respectively. In the gray ATBs, Orthokin, chlorhexidine, control, Listerine, and fluoride groups exhibited the highest force decay in descending order. In some groups, the differences between transparent and gray ATBs were significant. In the control group, the force of transparent ATB was significantly higher than gray ones on days 7 and 14 but not significantly after four weeks. Conclusion. ATBs’ force degradation could be exacerbated by the use of some mouth rinses. There were some differences between force relaxation patterns of transparent and gray ATBs. The data could be beneficial in choosing appropriate O-rings for making ATBs.

scholarly journals Comparison of force decay pattern in orthodontic elastomeric chains and NiTi closed coil springs, affected by five different mouthwashes: An in vitro Study

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Amir Hossein Mirhashemi ◽  
Niloofar Habibi Khameneh ◽  
Keyvan Shahpoorzadeh ◽  
Atefe Saffar Shahroudi
Keyword(s):  
Reduction Rate ◽  
In Vitro Study ◽  
Vitro Study ◽  
Control Group ◽  
Force Decay ◽  
Decay Pattern ◽  
Force Reduction ◽  
Initial Force ◽  
Elastomeric Chains

Background: The aim of this study was to compare the force decay pattern of elastomeric chains and NiTi coil springs which were exposed to five different commercially available mouthwashes.Methods: In this in vitro study, 60 pieces of elastomeric chain (EC) and 60 NiTi closed coil springs (CS) were divided into 6 groups. The specimens were exposed to one of these mouthwashes twice a day for 60 seconds:  Listerine, chlorhexidine, Orthokin, Persica, fluoride and artificial saliva as the control group. The elastomeric chains and NiTi springs were stretched so that they exert the initial force of 250 gr. Their force was measured on the 1, 7, 14 and 28 following days by means of a digital gauge.Results: Elastomeric chains and coil springs had force decrease over time, but EC' force reduction was greater with the highest reduction rate in the first week. However, in the CS group, the force decrease wasn't statistically significant in the first two weeks.  After 28 days in the control groups, 49.8% of the initial force was remained in ECs while the value was 93.3% for CSs. In comparison between mouthwashes, in EC groups, in all mouthwashes except Persica, the remained force was statistically less than control group.Conclusion: Force degradation of elastomeric chains could be exacerbated by use of mouthwashes. About coil springs, force decay was also observed. However, it was not statistically significant. Force reduction was detectable after four weeks of coil springs usage, but in EC groups, the greatest reduction was after the first week.  

scholarly journals Force Relaxation Characteristics of Medium Force Orthodontic Latex Elastics: A Pilot Study

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Daniel J. Fernandes ◽  
Gisele M. Abrahão ◽  
Carlos N. Elias ◽  
Alvaro M. Mendes
Keyword(s):  
Tensile Testing ◽  
Statistical Significance ◽  
Testing Machine ◽  
Force Extension ◽  
Time Period ◽  
Force Decay ◽  
Force Relaxation ◽  
Static Tensile ◽  
Decay Pattern ◽  
Relaxation Characteristics

To evaluate force extension relaxation of different brands and diameters of latex elastics subjected to static tensile testing under an apparatus designed to simulate oral environments, sample sizes of 5 elastics from American Orthodontics (AO), Tp, and Morelli Orthodontics (Mo) of equivalent medium force, (3/16, 1/4, and 5/16 inch size) were tested. The forces were read after 1-, 3-, 6-, 12- and 24-hour periods in Emic testing machine with 30 mm/min cross-head speed and load cell of 20 N. Two-way ANOVA and Bonferroni tests were used to identify statistical significance. There were statistically differences among different manufacturers at all observation intervals (P<0.0001). The relationships among loads at 24-hour time period were as follows: Morelli>AO>Tp for 3/16, 1/4, and 5/16 elastics. The force decay pattern showed a notable drop-off of forces until 3 hours, a slight increase in some groups from 3–6 hours and a more homogeneous force pattern over 6–24 hours.

scholarly journals In situ evaluation of orthodontic elastomeric chains

2012 ◽  
Vol 23 (4) ◽  
pp. 394-398 ◽  
Author(s):  
Carolina Baratieri ◽  
Cláudia Trindade Mattos ◽  
Matheus Alves Jr ◽  
Thiago Chon Leon Lau ◽  
Lincoln Issamu Nojima ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Testing Machine ◽  
Time Factors ◽  
Time Interval ◽  
Significance Level ◽  
Universal Testing ◽  
Initial Force ◽  
Post Hoc ◽  
Elastomeric Chains

The hypothesis tested in this study was that intraoral exposure of elastomeric chains alters their tensile strength. For such purpose, it was evaluated the in situ behavior of different elastomeric chains stretched for 3 weeks. Three kinds of elastomeric chains, Plastic chain (PC), Memory chain (MC) and Super slick chain (SSC), were randomly placed in 3 quadrants of 13 patient in a fixed distance of 16 mm and mean initial force of 180 g. Tensile testing was performed in an universal testing machine at different intervals: initial, 1 h, 24 h, 1 week, 2 weeks and 3 weeks. A two-way ANOVA test was performed to identify the influence of both material and time on the force decrease. A subsequent one-way ANOVAtest with the Tukey's post hoc test was used to identify statistically significant intragroup and intergroup remaining force (g and %) differences at 5% significance level. The effect of both the material and the time factors were significant. All groups showed significant force decrease after the 1-h period (23% for PC and 14% for MC and SSC). At the end of the 3-week period, the remaining force was 57% (96 g), 67% (129 g) and 71% (125 g) for PC, MC and SSC, respectively. In conclusion, intraoral exposure of elastomeric chains altered their tensile strength. In general, the greater force decrease occurred within the first hour. The remaining force of the enhanced chains measured at each time interval was greater than the conventional one (PC). After 3 weeks, only the enhanced chains maintained the force applied over 100 g.

Comparison of Three Commercial Latex and Non-Latex Orthodontic Elastic Bands

2019 ◽  
Vol 814 ◽  
pp. 354-359
Author(s):  
Sasatorn Malanon ◽  
Surachai Dechkunakorn ◽  
Niwat Anuwongnukroh ◽  
Wassana Wichai
Keyword(s):  
Mechanical Properties ◽  
Physical And Mechanical Properties ◽  
Physical Characteristics ◽  
Breaking Force ◽  
Cross Sectional ◽  
Force Decay ◽  
Elastic Bands ◽  
Extension Force ◽  
Inner Diameter ◽  
Initial Force

Orthodontic elastic bands are commonly made from natural rubber because they provide high resiliency at a reasonable cost. However, hypersensitivity related to protein present in latex have been reported in some patients which has led to increased usage of non-latex elastic alternatives. Therefore, the assessment of their mechanical properties is of importance. The objective of this study was to compare the physical and mechanical properties of three commercial latex and non-latex type orthodontic elastic bands. Samples of latex and non-latex type orthodontic elastics from manufacturers – AO (6.5oz), MASEL (6.0oz), GAC (6.0oz), with 3/16-inch diameter were selected. Firstly, the physical characteristics (width, cross-sectional thickness, and inner diameter) of the elastic bands were determined, following which their mechanical properties [initial extension force (F0), 24 h-residual force (F24), percentage of force decay, force exerted at 3 times the inner diameter (F3xID) and breaking force] were tested. The data were analyzed with Mann-Whitney U test and multiple comparisons among the groups were done with Kruskal-Wallis Test (p< 0.05). Significant differences were found in the physical characteristics and mechanical properties among each brand and type of elastics. AO elastic bands had significantly low F0 and F24 compared with the others. While the percentage of force decay at 24 h was greatest in AO followed by MASEL and GAC. Non-latex type elastics showed greater force decay than latex type ones, approximately 30-40% and 20-30% of the initial force in non-latex and latex type elastic, respectively. AO elastics showed the highest F3xID and also the lowest breaking force. Overall, non-latex type elastics exhibited lower breaking force compared to latex type ones. Wide variations were observed in the physical and mechanical characteristics among same manufacturer and same elastic type. All commercial brands presented higher F3xID than that stated by the manufacturers. Non-latex type elastics showed greater force decay over 24 h than latex type ones. The differences in the properties between the 2 types of the elastics could be due to the differences in their structure and polymers composition.

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