Ultrasonic Wave Velocity Measurement in Small Polymeric and Cortical Bone Specimens

1997 ◽  
Vol 119 (3) ◽  
pp. 232-236 ◽  
Author(s):  
S. S. Kohles ◽  
J. R. Bowers ◽  
A. C. Vailas ◽  
R. Vanderby
Keyword(s):  
Wave Propagation ◽  
Cortical Bone ◽  
Ultrasonic Wave ◽  
High Density Polyethylene ◽  
Polymeric Materials ◽  
High Density ◽  
Acoustic Properties ◽  
Propagation Time ◽  
System Delay ◽  
Normal Rat

A system was refined for the determination of the bulk ultrasonic wave propagation velocity in small cortical bone specimens. Longitudinal and shear wave propagations were measured using ceramic, piezoelectric 20 and 5 MHz transducers, respectively. Results of the pulse transmission technique were refined via the measurement of the system delay time. The precision and accuracy of the system were quantified using small specimens of polyoxymethylene, polystyrene-butadiene, and high-density polyethylene. These polymeric materials had known acoustic properties, similarity of propagation velocities to cortical bone, and minimal sample inhomogeneity. Dependence of longitudinal and transverse specimen dimensions upon propagation times was quantified. To confirm the consistency of longitudinal wave propagation in small cortical bone specimens (<1.0 mm), cut-down specimens were prepared from a normal rat femur. Finally, cortical samples were prepared from each of ten normal rat femora, and Young’s moduli (Eii), shear moduli (Gij), and Poisson ratios (vij) were measured. For all specimens (bone, polyoxymethylene, polystyrene-butadiene, and high-density polyethylene), strong linear correlations (R2 > 0.997) were maintained between propagation time and distance throughout the size ranges down to less than 0.4 mm. Results for polyoxymethylene, polystyrene-butadiene, and high-density polyethylene were accurate to within 5 percent of reported literature values. Measurement repeatability (precision) improved with an increase in the wave transmission distance (propagating dimension). No statistically significant effect due to the transverse dimension was detected.

Simulation study of axial ultrasonic wave propagation in heterogeneous bovine cortical bone

2016 ◽  
Vol 140 (5) ◽  
pp. 3710-3717 ◽  
Author(s):  
Toshiho Hata ◽  
Yoshiki Nagatani ◽  
Koki Takano ◽  
Mami Matsukawa
Keyword(s):  
Wave Propagation ◽  
Cortical Bone ◽  
Ultrasonic Wave ◽  
Simulation Study ◽  
Ultrasonic Wave Propagation

scholarly journals Corrosion Inhibition Efficiencies of Polymeric Materials on Alloy Steel in Dilute Hydrochloric Acid and Sodium Hydroxide Solutions at Ambient Temperature

2020 ◽  
Vol 7 (2) ◽  
pp. C27-C32
Author(s):  
I.E. Ekengwu ◽  
O.G. Utu ◽  
K.O. Anyanwu
Keyword(s):  
Corrosion Rate ◽  
Ambient Temperature ◽  
Alloy Steel ◽  
Corrosion Inhibition ◽  
High Density Polyethylene ◽  
Inhibition Efficiency ◽  
Polymeric Materials ◽  
High Density ◽  
Alkaline Solutions ◽  
Ph Values

A corrosion control test was conducted on alloy steel, using polymeric coatings (polyurethane, bitumen (medium airing), and high-density polyethylene) in dilute HCl solutions of pH values 4, 7, and 12, respectively for acid, neutral and alkaline solutions at ambient temperature. In the study, Eighty-four coupons of alloy steel were used. The coupons were mechanized, ground, polished, etched with natal, and weighed using a digital weighing balance (Beva 206B). The mass of each coupon was recorded according to the tag number on them. Twenty-one of the coupons were coated with polyurethane, 21 coated with medium curing bitumen (MC), and 21 coated with high-density polyethylene, while 21 were left uncoated. Seven polyurethane-coated samples, bitumen coating, and uncoated coupons were suspended in dilute HCl solutions of pH values 4, 7, and 12. Every week, one sample is taken from each of the solutions, the coatings and the corrosion products were removed, and the coupons were etched with natal. Then the coupons were reweighed, and their masses were recorded in accordance with their tag number. The weight loss per unit area of the coupons, corrosion rate, and percentage corrosion inhibition efficiencies of the coatings was calculated over seven weeks. The results obtained were tabulated and represented graphically. From the results obtained, it is seen that the corrosion inhibition efficiency of polyurethane coatings is higher compared with bitumen and polyethylene. It is also seen from the graphs that the corrosion rate of the coupons is higher in acid, a little bit lower in alkaline, and much lower in neutral solution. It is also observed that the corrosion rates fall with time as the inhibition efficiency also falls with time.

Electrical and dielectric sensitivities to thermal processes in carbon nanofiber/high-density polyethylene composites

2011 ◽  
Vol 18 (1-2) ◽  
pp. 51-60 ◽  
Author(s):  
Tian Liu ◽  
Weston Wood ◽  
Bin Li ◽  
Brooks Lively ◽  
Wei-Hong Zhong
Keyword(s):  
Dielectric Properties ◽  
Thermal Treatment ◽  
High Density Polyethylene ◽  
Ac Conductivity ◽  
Elevated Temperatures ◽  
Carbon Nanofiber ◽  
Polymeric Materials ◽  
High Density ◽  
Heating Process ◽  
Thermal Processes

AbstractOwing to the huge interface region existing in a polymer nanocomposite, the effects of thermal processes on properties of nanocomposites are much more complicated than in a pure polymer. It is therefore important to determine the effects of thermal processes on nanocomposites with different interfacial interactions between the nanofillers and the polymer matrix. It is also important to explore the performance changes for nanocomposites under elevated temperatures over pure polymers. In this investigation, we examined the correlation of thermal treatment with dielectric properties of carbon nanofiber (CNF) reinforced high-density polyethylene nanocomposites. The thermal treatment of specimens was conducted for up to 120 h at 87°C and 127°C. Then, alternating current (AC) conductivity and dielectric properties were tested after definite intervals of time. Their changing rates over treatment time were analyzed. The results revealed the approximate linear relationships of AC conductivity and dielectric constant vs. heating time. Modified CNF reinforced nanocomposites had less influence by the heating treatments exhibiting better thermal resistance. The change rates of AC conductivity σ and dielectric properties have higher sensitivity to the treatment at a higher temperature. This study provides potential for further research on application of electrical and dielectric signals to detect the effects of heating process on lifetime of polymeric materials.

Nanocomposite Polymeric Materials Based on Butyl Rhodamine B Incorporated in Mesoporous Films of High-Density Polyethylene

2020 ◽  
Vol 90 (4) ◽  
pp. 737-742
Author(s):  
O. V. Arzhakova ◽  
A. A. Dolgova ◽  
A. Yu. Kopnov ◽  
A. I. Nazarov ◽  
A. Yu. Yarysheva ◽  
...  
Keyword(s):  
Rhodamine B ◽  
High Density Polyethylene ◽  
Polymeric Materials ◽  
High Density ◽  
Mesoporous Films ◽  
Butyl Rhodamine B

Study on the solidification kinetics of high-density polyethylene during thin-walled injection molding process

2012 ◽  
Vol 32 (6-7) ◽  
pp. 355-363 ◽  
Author(s):  
Shuang-quan Deng ◽  
Bin Yang ◽  
Ji-bin Miao ◽  
Ru Xia ◽  
Jia-sheng Qian ◽  
...  
Keyword(s):  
Injection Molding ◽  
High Density Polyethylene ◽  
Polymeric Materials ◽  
High Density ◽  
Injection Molding Process ◽  
Structure Property ◽  
X Ray Diffraction ◽  
Molding Process ◽  
Solidification Kinetics ◽  
Thin Walled

Abstract In this work, the effect of the initial and secondary temperature differences on the solidification behaviors of high-density polyethylene (HDPE) during the thin-walled injection molding (TWIM) was intensively investigated. Simulated temperature profiles using the enthalpy transformation methodology were compared with an in situ temperature measurement, and reasonable agreement was achieved between calculations and measurements. Two-dimensional wide-angle X-ray diffraction characterization shows that the formation of oriented crystal structures was considerably affected by the thermal gradient within the injection-molded article. The present study can be practically significant to the optimization of the cooling parameters during the TWIM of crystalline polymers as well as to the further study on the relationship among “processing-structure-property” of polymeric materials.

Influence of a gradient of material properties on ultrasonic wave propagation in cortical bone: Application to axial transmission

2009 ◽  
Vol 125 (6) ◽  
pp. 4043-4052 ◽  
Author(s):  
Guillaume Haïat ◽  
Salah Naili ◽  
Quentin Grimal ◽  
Maryline Talmant ◽  
Christophe Desceliers ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Cortical Bone ◽  
Ultrasonic Wave ◽  
Material Properties ◽  
Ultrasonic Wave Propagation ◽  
Axial Transmission
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