Fabrication and Mechanical Properties of Double-Shell Thermal Energy Storage Microcapsules Applied as Environmental Temperature-Controlling Materials in Building

The aim of the present work was to fabricate heat energy storage microcapsules, which could be used in indoor-wall materials as environmental temperature-controller. Melamine formaldehyde resin (MF) double-shell structure microcapsules were fabricated and the mechanical properties of shell were investigated. The average diameter of microcapsules was in the range of 5-10 μm, and the globular surface was smooth and compact. The mechanical properties of shell were evaluated through observing the surface morphological structure change after pressure by means of scanning electron microscopy (SEM). The results showed that a yield point was found both on single and double shell, and when the press was beyond the point the microcapsules showed plastic behavior. In addition, the mechanical intensity of double-shell microcapsules was better than that of single shell. Analysis of DSC indicated that the phase change temperature was not affected by the double –shell structure.

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Exergy Analysis of Thermal Energy Storage With Specific Remarks on the Variation of the Environmental Temperature

Journal of Solar Energy Engineering ◽

10.1115/1.2848020 ◽

1996 ◽

Vol 118 (2) ◽

pp. 81-88 ◽

Cited By ~ 2

Author(s):

G. Bisio

Keyword(s):

Energy Storage ◽

Constant Temperature ◽

Exergy Analysis ◽

Environmental Temperature ◽

Variable Temperature ◽

Thermal Storage ◽

Exergy Efficiency ◽

Basic Question ◽

Storage Devices ◽

Temperature Environment

Energy storage is a key technology for many purposes and in particular for air conditioning plants and a successful exploitation of solar energy. Thermal storage devices are usually classified as either variable temperature (“sensible heat”) or constant temperature (“latent heat”) devices. For both models a basic question is to determine the efficiency suitably: Only exergy efficiency appears a proper way. The aim of this paper is to examine exergy efficiency in both variable and constant temperature systems. From a general statement of exergy efficiency by the present author, two types of actual definitions are proposed, depending on the fact that the exergy of the fluid leaving the thermal storage during the charge phase can be either totally lost or utilized elsewhere. In addition, specific remarks are made about the exergy of a system in a periodically varying temperature environment.

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Effect of Defect on Elastic/Plastic and Creep Behavior of Bone: A Finite Element Study

ASME 2007 Summer Bioengineering Conference ◽

10.1115/sbc2007-175843 ◽

2007 ◽

Author(s):

A. Ajdari ◽

P. K. Canavan ◽

H. Nayeb-Hashemi ◽

G. Warner

Keyword(s):

Mechanical Properties ◽

Finite Element ◽

Trabecular Bone ◽

Fatigue Loading ◽

Dimensional Structure ◽

Plastic Behavior ◽

Element Analysis ◽

Elastic Plastic ◽

Local Bone ◽

Osteoporotic Vertebral Fractures

Three-dimensional structure of trabecular bone can be modeled by 2D or 3D Voronoi structure. The effect of missing cell walls on the mechanical properties of 2D honeycombs is a first step towards understanding the effect of local bone resorption due to osteoporosis. In patients with osteoporosis, bone mass is lost first by thinning and then by resorption of the trabeculae [1]. Furthermore, creep response is important to analyze in cellular solids when the temperature is high relative to the melting temperature. For trabecular bone, as body temperature (38 °C) is close to the denaturation temperature of collagen (52 °C), trabecular bone creeps [1]. Over the half of the osteoporotic vertebral fractures that occur in the elderly, are the result of the creep and fatigue loading associated with the activities of daily living [2]. The objective of this work is to understand the effect of missing walls and filled cells on elastic-plastic behavior of both regular hexagonal and non-periodic Voronoi structures using finite element analysis. The results show that the missing walls have a significant effect on overall elastic properties of the cellular structure. For both regular hexagonal and Voronoi materials, the yield strength of the structure decreased by more than 60% by introducing 10% missing walls. In contrast, the results indicate that filled cells have much less effect on the mechanical properties of both regular hexagonal and Voronoi materials.

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Manufacture of thin rice straw particleboards bonded with various polymeric methane diphenyl diisocyanate/ urea formaldehyde resin mixtures

BioResources ◽

10.15376/biores.15.1.935-944 ◽

2019 ◽

Vol 15 (1) ◽

pp. 935-944

Author(s):

Peng Luo ◽

Chuanmin Yang ◽

Mengyao Li ◽

Yueqi Wang

Keyword(s):

Mechanical Properties ◽

Rice Straw ◽

Water Resistance ◽

Urea Formaldehyde ◽

Single Layer ◽

Formaldehyde Resin ◽

Manufacturing Cost ◽

Board Density ◽

Layer Medium ◽

Resin Formulation

Reducing particleboard thickness is one of the major approaches to decrease consumption volume of particleboard for furniture manufacture. This study employed an adhesive mixture of polymeric methane diphenyl diisocyanate (PMDI) and urea formaldehyde (UF) to produce single-layer medium density thin rice straw particleboard. The effects of various PMDI/UF formulations as well as board density on mechanical properties and water resistance of rice straw particleboard were studied. The results indicated that the mechanical properties and water resistance of the thin rice straw particleboard were appreciably affected by resin formulation. The panels bonded with PMDI/UF adhesive mixtures had mechanical properties and water resistance far superior to those bonded with UF. Higher PMDI content levels in resin mixtures led to improved mechanical properties and water resistance. Density influenced mechanical properties and water resistance of the thin rice straw particleboard. Increasing the density of the panel could upgrade the mechanical properties of the thin rice straw particleboard. The experimental outcomes showed that PMDI/UF resin systems had potential to substitute for pure PMDI resin in producing thin rice straw particleboard, which could effectively lower manufacturing cost and bring economic efficiencies due to reduced amount of pricey PMDI.

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Paraffin/red mud phase change energy storage composite incorporated gypsum-based and cement-based materials: Microstructures, thermal and mechanical properties

Journal of Hazardous Materials ◽

10.1016/j.jhazmat.2018.10.061 ◽

2019 ◽

Vol 364 ◽

pp. 608-620 ◽

Cited By ~ 11

Author(s):

Zhiyong Liu ◽

Shu Zhang ◽

Dan Hu ◽

Yunsheng Zhang ◽

Henglin Lv ◽

...

Keyword(s):

Mechanical Properties ◽

Energy Storage ◽

Phase Change ◽

Red Mud ◽

Thermal And Mechanical Properties ◽

Cement Based Materials

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Mechanical properties of the tracheal mucosal membrane in the rabbit. II. Morphometric analysis

Journal of Applied Physiology ◽

10.1152/jappl.2000.88.3.1022 ◽

2000 ◽

Vol 88 (3) ◽

pp. 1022-1028 ◽

Cited By ~ 10

Author(s):

Lu Wang ◽

Kenneth L. Pinder ◽

Joel L. Bert ◽

Mitsushi Okazawa ◽

Peter D. Paré

Keyword(s):

Mechanical Properties ◽

Volume Fraction ◽

Mechanical Load ◽

Morphological Structure ◽

Longitudinal Direction ◽

Smooth Muscle Contraction ◽

Elastic Fibers ◽

Tissue Samples ◽

Mucosal Membrane ◽

Simple Geometry

Folding of the airway mucosal membrane provides a mechanical load that impedes airway smooth muscle contraction. Mechanical testing of rabbit tracheal mucosal membrane showed that the membrane is stiffer in the longitudinal than in the circumferential direction of the airway. To explain this difference in the mechanical properties, we studied the morphological structure of the rabbit tracheal mucosal membrane in both longitudinal and circumferential directions. The collagen fibers were found to form a random meshwork, which would not account for differences in stiffness in the longitudinal and circumferential directions. The volume fraction of the elastic fibers was measured using a point-counting technique. The orientation of the elastic fibers in the tissue samples was measured using a new method based on simple geometry and probability. The results showed that the volume fraction of the elastic fibers in the rabbit tracheal mucosal membrane was ∼5% and that the elastic fibers were mainly oriented in the longitudinal direction. Age had no statistically significant effect on either the volume fraction or the orientation of the elastic fibers. Linear correlations were found between the steady-state stiffness and the quantity of the elastic fibers oriented in the direction of testing.

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Tribology study of hydroxyapatite (HAp) scaffold blended single based binder via rheology and mechanical properties

Industrial Lubrication and Tribology ◽

10.1108/ilt-09-2016-0228 ◽

2017 ◽

Vol 69 (3) ◽

pp. 414-419

Author(s):

Mimi Azlina Abu Bakar ◽

Siti Norazlini Abd Aziz ◽

Muhammad Hussain Ismail

Keyword(s):

Mechanical Properties ◽

Injection Molding ◽

Palm Stearin ◽

Polymeric Materials ◽

High Energy ◽

Single Step ◽

Injection Molding Process ◽

Plastic Behavior ◽

Molding Process ◽

Content Type

Purpose This paper aims to investigate the vital characteristic of an innovative ceramic injection molding (CIM) process for orthopedic application with controlled porosity and improved tribological and mechanical properties which were affected by complex tribological interactions, whether lubricated like hip implants and other artificial prostheses. The main objective is to maximize the usage of palm stearin as a single based binder as the function of flow properties during injection molding process. Design/methodology/approach The binder used in this present study consists of 100 per cent palm stearin manufactured by Kempas Oil Sdn Bhd and supplied by Vistec Technology Sdn Bhd. The feedstock was prepared by using a Z-blade mixer (Thermo Haake Rheomix OS) and Brabender mixer model R2400. The feedstock prepared was injection molded using a manually operated vertical benchtop machine with an average pressure of about 5-7 bars. The firing step included the temporary holds at intermediate temperatures to burn out organic binders. At this stage, the green molded specimen was de-bound using a single-step wick-debinding method. Findings The maximum content of ceramic material is applied to investigate the efficiencies of net formulation that can be achieved by ceramic materials. The longer the viscosity will change with shear rate, the higher the value of n obtained instead. From the slope of the curves obtained in Figure 3, the value of n for the feedstock was determined to be less than 1, which indicates a pseudoplastic behavior and suitability for the molding process. Moreover, high shear sensitivity is important in producing complex and intrinsic specimens which are leading products in the CIM industry. Originality/value The feedstock containing HAp powder and palm stearin binder was successfully prepared at very low temperature of 70°C, which promoting a required pseudo-plastic behavior during rheological test. The single binder palm stearin should be optimized in other research works carried out, as palm stearin is most preferred compared to other polymeric materials that provided high energy consumption when subjected to the sintering process. Besides the binder is widely available in Malaysia, low cost and harmless effect during debinding process.

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