scholarly journals Effect of Ultraviolet-A (UV-A) and Ultraviolet-C (UV-C) Light on Mechanical Properties of Oyster Mushrooms during Growth

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Tindibale L. Edward ◽  
M. S. K. Kirui ◽  
Josiah O. Omolo ◽  
Richard G. Ngumbu ◽  
Peter M. Odhiambo
Keyword(s):  
Mechanical Properties ◽  
Storage Modulus ◽  
Loss Factor ◽  
Loss Modulus ◽  
Control Sample ◽  
Ultraviolet A ◽  
Significant Difference ◽  
Ultraviolet C ◽  
Oyster Mushrooms ◽  
Uv C

This study investigated the effects of ultraviolet-A (UV-A) and ultraviolet-C (UV-C) light on the mechanical properties in oyster mushrooms during the growth. Experiments were carried out with irradiation of the mushrooms with UV-A (365 nm) and UV-C (254 nm) light during growth. The exposure time ranged from 10 minutes to 60 minutes at intervals of 10 minutes and irradiation was done for three days. The samples for experimental studies were cut into cylindrical shapes of diameter 12.50 mm and thickness 3.00 mm. The storage modulus, loss modulus, and loss factor of the irradiated samples and control samples were determined for both UV bands and there was a significant difference between the storage modulus, loss modulus, and loss factor of the irradiated samples by both UV bands with reference to the control sample, P<0.05. UV-C light irradiated samples had higher loss modulus and loss factor but low storage modulus as temperature increased from 35 to 100°C with respect to the control sample while UV-A light irradiated samples had lower loss modulus, low loss factor, and higher storage modulus than UV-C irradiated samples.

scholarly journals Simultaneous Characterization of Relaxation, Creep, Dissipation, and Hysteresis by Fractional-Order Constitutive Models

2021 ◽  
Vol 5 (2) ◽  
pp. 36
Author(s):  
Jun-Sheng Duan ◽  
Di-Chen Hu ◽  
Yang-Quan Chen
Keyword(s):  
Constitutive Model ◽  
Storage Modulus ◽  
Loss Factor ◽  
Creep Compliance ◽  
Loss Modulus ◽  
Constitutive Models ◽  
Stationary Points ◽  
Logarithmic Scale ◽  
Zener Model ◽  
Fractional Zener Model

We considered relaxation, creep, dissipation, and hysteresis resulting from a six-parameter fractional constitutive model and its particular cases. The storage modulus, loss modulus, and loss factor, as well as their characteristics based on the thermodynamic requirements, were investigated. It was proved that for the fractional Maxwell model, the storage modulus increases monotonically, while the loss modulus has symmetrical peaks for its curve against the logarithmic scale log(ω), and for the fractional Zener model, the storage modulus monotonically increases while the loss modulus and the loss factor have symmetrical peaks for their curves against the logarithmic scale log(ω). The peak values and corresponding stationary points were analytically given. The relaxation modulus and the creep compliance for the six-parameter fractional constitutive model were given in terms of the Mittag–Leffler functions. Finally, the stress–strain hysteresis loops were simulated by making use of the derived creep compliance for the fractional Zener model. These results show that the fractional constitutive models could characterize the relaxation, creep, dissipation, and hysteresis phenomena of viscoelastic bodies, and fractional orders α and β could be used to model real-world physical properties well.

scholarly journals The effect of calcinated hydroxyapatite and magnesium doped hydroxyapatite as fillers on the mechanical properties of a model BisGMA/TEGDMA dental composite initially and after aging

10.30544/403 ◽  
2018 ◽  
Vol 24 (4) ◽  
Author(s):  
Tamara Matic ◽  
Maja Ležaja Zebić ◽  
Ivana Cvijović-Alagić ◽  
Vesna Miletić ◽  
Rada Petrović ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Body Fluid ◽  
Control Sample ◽  
Dental Composite ◽  
In Vitro Bioactivity ◽  
Significant Difference ◽  
Nanosized Hydroxyapatite ◽  
Glass Fillers ◽  
Mg Doped

The aim of this study was to investigate the possibility of modifying model BisGMA/TEGDMA dental composite by substituting 10 wt. % of conventional glass fillers with bioactive fillers based on calcinated nanosized hydroxyapatite (HAp) and Mg doped hydroxyapatite (Mg-HAp). HAp and Mg-HAp powders were synthesized hydrothermally. Mechanical properties: hardness by Vickers (HV) and flexural strength (Fs) were tested initially and after being stored for 28 days in simulated body fluid (SBF). The experimental composites with HAp and Mg-HAp particles showed no statistically significant difference in HV compared to the control (p>0.05) either initially or after storage. Although mean Fs values of modified composites tested initially were lower (62 MPa) than those of the control (72 MPa), after 28 days of storage in SBF Fs values were greater for modified composites (42 MPa control sample, 48 MPa HAp and Mg-HAp samples). In vitro bioactivity of BisGMA/TEGDMA composites with HAp and Mg-HAp particles after 28 days in SBF was not detected. Keywords: hydroxyapatite; magnesium; dental composite; mechanical properties;

The Irradiation Crosslinking of Poly(vinylidene fluoride-​chlorotrifluoroethylene)

2014 ◽  
Vol 716-717 ◽  
pp. 7-10
Author(s):  
Jian Chen
Keyword(s):  
Mechanical Properties ◽  
Storage Modulus ◽  
Ultraviolet Irradiation ◽  
Vinylidene Fluoride ◽  
Loss Modulus ◽  
Great Influence ◽  
Poly Vinylidene Fluoride ◽  
Content Support

Vinylidenefluoride (VDF) and chlorotrifluoroethylene (CTFE) copolymers were crosslinked by ultraviolet irradiation, chlorotrifluoroethylene content has a great influence on the crosslinked copolymers, high CTFE content support more joint pots, the properties of the copolymer shows higher storage modulus, the loss modulus gets smaller. The copolymer mechanical properties gets much higher.

The Property of Waterborne UV-Curable Polyurethane Based on Alkali Lignin of Wheat Straw

2013 ◽  
Vol 834-836 ◽  
pp. 199-202 ◽  
Author(s):  
Ji Lei Chao ◽  
Fu Qiang Chu ◽  
Chang Li Xu ◽  
Hui Wang ◽  
Yu Xin Liu
Keyword(s):  
Mechanical Properties ◽  
Optical Properties ◽  
Wheat Straw ◽  
Loss Factor ◽  
Loss Modulus ◽  
Added Value ◽  
Light Transmittance ◽  
Optical Performance ◽  
Uv Curable ◽  
Alkali Lignin

To improve the added value of lignin, the modified alkali lignin of wheat straw was used to prepare waterborne UV-curable polyurethane. The purpose of this paper is to discuss the properties of the cured films made from the above lignin-based polyurethane. The mechanical and optical properties of the cured films were investigated. Results showed that the tensile storage modulus, tensile loss modulus, and tensile loss factor of the cured film were influenced by the addition of the lignin, which indicated that proper dosage of the lignin could change the micro-phase separation structure and improve the mechanical properties of the product. The addition of the lignin also influenced the gloss and light transmittance of the cured film. On the whole, the lignin-based polyurethane exhibits good mechanical and optical performance if proper proportion of the lignin was added to the product. The study was beneficial for utilizing the lignin in high value products.

REACTIVE COMPATIBILIZATION OF THE BLENDS OF THERMOPLASTIC POLYURETHANE AND POLYDIMETHYLSILOXANE RUBBER

2015 ◽  
Vol 88 (4) ◽  
pp. 584-603 ◽  
Author(s):  
Jineesh Ayippadath Gopi ◽  
Golok Bihari Nando
Keyword(s):  
Mechanical Properties ◽  
Storage Modulus ◽  
Loss Modulus ◽  
Thermoplastic Polyurethane ◽  
Domain Size ◽  
Damping Factor ◽  
Creep Tests ◽  
Dynamic Mechanical ◽  
Compatibilization Effect ◽  
Compatibilized Blends

ABSTRACT The effect of ethylene-co-methacrylate (EMA) as polymeric chemical compatibilizer on the mechanical, dynamic mechanical, phase morphology, adhesion, and rheological properties of the blends of thermoplastic polyurethane (TPU)–polydimethylsiloxane rubber (PDMS) was investigated at different blend ratios. Melt blending technique was used to prepare the compatibilized blends. Enhancement of the mechanical properties and the reduction of dispersed PDMS domain size in the alloy confirmed the compatibilization effect of EMA on TPU-PDMS blends. Dynamic mechanical properties such as storage modulus, loss modulus, and the damping factor were evaluated to assess the compatibilization effect of EMA on TPU-PDMS blends. Creep tests revealed that compatibilization led to better dimensional stability. Compatibilized blends with finer PDMS rubber domains showed relatively less reduction in storage modulus as compared with uncompatibilized blends during stress relaxation studies. Rheological analysis suggested that the incorporation of EMA decreased the interfacial slip between the blend constituents, and this also confirmed the compatibilization effect of EMA on TPU-PDMS rubber blends as a polymeric reactive compatibilizer.

Study on Dynamic Mechanical Properties of n-HA/PA66 Composites

2011 ◽  
Vol 418-420 ◽  
pp. 1511-1515
Author(s):  
Lin Cheng ◽  
Xiang Zhang ◽  
Yu Bao Li
Keyword(s):  
Mechanical Properties ◽  
Storage Modulus ◽  
Loss Modulus ◽  
Physiological Saline ◽  
Dynamic Mechanical Properties ◽  
Intrinsic Properties ◽  
Polyamide 66 ◽  
Dynamic Mechanical ◽  
Reinforcing Effects

The dynamic mechanical properties of nano-hydroxyapatite (n-HA) reinforced polyamide 66 (PA66) biocomposites were studied with reference to the effect of n-HA content, frequency and physiological saline. The intrinsic properties of the components, morphology of the system and the nature of interface between the phases determine the dynamic mechanical properties of the composite. The storage modulus (E') values of n-HA/PA66 composites were much higher than those of pure PA66, indicating that the incorporation of n-HA in PA66 matrix induced reinforcing effects obviously. And the E' values of composites increased with increasing of n-HA content. The loss modulus (E") of the composite with 30wt% n-HA was higher that those of pure PA66 and the composite with 40wt% n-HA below 55°C, however, above 55°C, the E" values enhanced with increase of n-HA content. Both frequency and physiological saline had obvious effects on the dynamic mechanical properties for n-HA/PA66 composite. E' and E" values enhanced with increase of frequency, but tanδ values decreased with increasing of frequency. After soaked in physiological saline, the E' and E" values of the composite decreased.

scholarly journals Dynamic mechanical analysis of nylon 6 fiber-reinforced acrylonitrile butadiene rubber composites

2021 ◽  
pp. 096739112110461
Author(s):  
C Rajesh ◽  
P Divia ◽  
S Dinooplal ◽  
G Unnikrishnan ◽  
E Purushothaman
Keyword(s):  
Mechanical Properties ◽  
Storage Modulus ◽  
Loss Modulus ◽  
Dynamic Mechanical Properties ◽  
Damping Factor ◽  
Butadiene Rubber ◽  
Bonding Agents ◽  
Fiber Loading ◽  
Dynamic Mechanical ◽  
Acrylonitrile Butadiene Rubber

Dynamic mechanical properties of polymeric materials are of direct relevance to a range of unique polymer applications. The aim of the study is to investigate the dynamic mechanical properties of composites of short nylon 6 fiber with acrylonitrile butadiene rubber (NBR). The storage modulus (G′), loss modulus (G″), and the damping factor (tan δ) have been analyzed with reference to the effects of fiber loading, curing systems, and bonding agents over a range of temperature and at varying frequencies. The storage modulus increases with increment in fiber loading, whereas loss modulus and damping factor decrease. The glass transition temperature shifts to higher temperature upon increment in fiber loading. Dicumyl peroxide (DCP)–cured composites show higher storage modulus and lower damping than the corresponding sulfur-cured one. The addition of hexa-resorcinol and phthalic anhydride as bonding agents enhances the dynamic mechanical properties of the composites. The experimental results have been evaluated by comparing with Einstein, Guth, and Nielsen models.

scholarly journals Effect of Conditioning Methods on Mechanical Properties of Raw Bael Fruit

2021 ◽  
Author(s):  
Indrajeet Sahu ◽  
Kalpana Rayaguru ◽  
Rashmi Ranjan Pattnaik ◽  
Sanjaya Kumar Dash
Keyword(s):  
Mechanical Properties ◽  
Testing Machine ◽  
Control Sample ◽  
Value Added ◽  
Hot Water ◽  
Rupture Force ◽  
Ambient Conditions ◽  
Significant Difference ◽  
Health Promoting ◽  
Normal Water

Background: Bael is an important indigenous fruit, which is rich in nutritional and health promoting factors. Development of value-added products from this fruit poses a problem as the fruit has a hard rind and is difficult to be removed by hand. Methods: The objective of this investigation was to evaluate the effect of different conditioning methods as normal water dipping (25-27°C), chilling (10-11°C), freezing (4-5°C) and hot water dipping (90-95°C) on firmness and other mechanical properties of raw and matured bael fruit, with a goal of devising some methods for easy removal of the rind. The fruits after conditioning were subjected to puncture test by universal testing machine. Distinct peaks were observed on the force-displacement traces which indicated the rupture force and firmness of the fruits. The changes observed in rupture force, deformation and firmness in conditioned samples were compared. Result: Rupture force measured for control sample (kept under ambient conditions) was 344.4±27.13 N and was found to be lower than that of the conditioned samples. The minimum rupture force of 192.6±14.41 N was observed in frozen sample. No significant difference in rupture force could be observed between the normal water dipped sample and chilled samples. Hot water dipped sample required a rupture force of 215.3±29.2 N, which was not significantly (p greater than 0.05) less than those of other treatments but, the green color of the fruits degraded to brown. The change in other mechanical properties also remained similar. The results would be useful for preparing the raw bael fruit for further processing and value addition.

Dynamic mechanical behavior of composite materials reinforced by graphene and huntite minerals

2021 ◽  
Vol 63 (12) ◽  
pp. 1090-1096
Author(s):  
Dilek Atilla ◽  
Binnur Gören
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Storage Modulus ◽  
Loss Modulus ◽  
Damping Ratio ◽  
Weight Percent ◽  
Dynamic Mechanical Properties ◽  
Grain Structure ◽  
Dynamic Mechanical ◽  
Pure Resin

Abstract The aim of this study is to investigate the dynamic mechanical properties of composite materials reinforced by mineral experimentally. Graphene and huntite minerals were added to epoxy resin at different weight ratios (wt.-%) as 0.5 weight percent, 1 weight percent and 3 weight percent, to examine the effect of mineral types and percentages on the resulting dynamic mechanical properties. In addition, the effect of non-layered huntite unlike graphene, with a nano-sized grain structure, was investigated. Thus, glass transition temperature (Tg), storage modulus (E’), loss modulus (E”) and damping ratio (tan δ) values were determined and compared. Moreover, a tensile test was performed in order to explain the relation between stress and strain. It was seen that adding different minerals caused different results according to types and proportions. In general, adding minerals to the pure resin increased the storage modulus and loss modulus, whereas the damping ratio (tan δ) decreased compared to the pure resin.

Dynamic nanomechanical response of nacre

2006 ◽  
Vol 21 (8) ◽  
pp. 2045-2051 ◽  
Author(s):  
Bedabibhas Mohanty ◽  
Kalpana S. Katti ◽  
Dinesh R. Katti ◽  
Devendra Verma
Keyword(s):  
Mechanical Properties ◽  
Loss Factor ◽  
Dynamic Properties ◽  
Loss Modulus ◽  
Spectroscopic Studies ◽  
Increase With Increase ◽  
Nanocomposite System ◽  
Brick And Mortar ◽  
Tan Δ ◽  
Dynamic Nanoindentation

Nacre, the shiny inner layer of mollusk shells is a model biomimetic nanocomposite system. Its exceptional mechanical properties have been the inspiration for materials scientists for several decades. Nacre exhibits a layered brick and mortar structure. It is composed of 95% inorganic (aragonitic CaCO3) phase and 5% organic (mainly proteins and polysaccharides) phase that are arranged in interlocked brick and mortar architecture with the mineral as bricks and organics as the mortar. In the current work, we describe the dynamic nanomechanical behavior of nacre using dynamic nanoindentation (nano-DMA) experiments. Two sets of loads were applied to obtain the dynamic response from varying depths in nacre. These tests were performed at three different frequencies (25, 50, and 100 Hz) to study the effect of frequency on the dynamic properties of nacre. The loss modulus (E″) and the loss factor (tan δ) were measured. Both of these parameters were observed to increase with increase in depth. Significant increase in tan δ was observed with the increase in frequency. Photoacoustic Fourier transform infrared spectroscopic studies on nacre indicate the presence of water in nacre. This water may be present at nanograin interfaces in nacre platelets, at organic–inorganic interfaces, and also in the organic phase in nacre. We believe that water is one of the significant contributors to the viscoelasticity of nacre. Our results indicate that the aragonite platelets in nacre may also contribute to viscoelasticity.

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