nano materials have been widely used in laboratory and industrial scales in order to improve various properties of concrete and concrete mixture. the mainstream practice of the researches in this field is to add metallic nano-particles into the concrete mixture. the present research focuses on adding micro-nano air bubbles (mnab) into water before mixing it with aggregate and cement mixtures. i...

In this work, tensile and yield stress and tensile and yield strain of oblique layer functionally graded steels produced by electroslag remelting were investigated. Functionally graded steels containing ferrite, austenite, bainite, and/or martensite layers may be fabricated via diffusion of alloying elements during the remelting stage. Tensile and yield stress and tensile and yield strain of fu...

Online and offline monitoring of composite bolted joints under tensile load were investigated using piezoelectric transducers. The relationships between Lamb wave signals, pre-tightening force, the applied tensile load, as well as the failure modes were investigated. Results indicated that S0/A0 wave amplitudes decrease with the increasing of load. Relationships between damage features and S0/A...

Polyvinyl ester green composites were synthesized with walnut shell powder (WSP) by in-situ polymerization technique. The green composites have been evaluated for mechanical properties such as tensile strength, tensile modulus and hardness. Sliding wear loss, specific wear rate and coefficient of friction were investigated by using computerized pin-on–disc machine at normal applied loads of 20,...

In this paper, experimental and Finite Element Methods have been used to determine mechanical properties of nanocomposites. Standard tensile and compression samples with 0.0, 0.15, 0.25, 0.35, 0.45, and 0.55 weight fraction of Multi-Walled Carbon Nanotube (MWCNT) were prepared and tested. Nanotube weight fraction was varied to investigate the effects of nanotube weight fraction on nanocomposite...

Objective(s): One of the main constraints of collagen hydrogel scaffolds for using in tissue engineering is mechanical weakness. Plastic compression (PC) is a physical method to overcome the mechanical limitation of collagen hydrogel. Materials and Methods: In this study, the effects of pH on mechanical and biological properties of PC hydrogels were investigated. Collagen hydrogels were fabrica...

BACKGROUND AND PURPOSE Several studies have shown that nicotine has a detrimental effect on the development of rotator cuff tear. However, little is known about its mechanism. We evaluated the effect of nicotine on the maximum tensile load, the maximum tensile stress, and the elastic modulus of the supraspinatus tendon in a rat model. METHODS 27 rats were randomly assigned to 3 groups. Subcut...

Compression therapy is frequently used to prevent hypertrophy of post-burn scars. This pilot study was performed in 6 patients to assess non-invasive changes induced in the tensile strength of the skin before any clinical improvement can be perceived. Assessments were performed using a computerized suction device delivering three 5 s cycles of 500 mbar depression. Measurements were made at one-...

In this paper, crashworthiness characteristics of conical steel tubes stiffened by annular rings and rigid polyurethane foam are investigated. For this purpose, wide circumferential rings are created from the outer surface of the conical tube at some determined areas along tube length. In fact, this method divides a long conical tube into several tubes of shorter length. When this structure is ...