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The use of fine fiber has become an important design tool for filter media. Nanofibers-based filter media have some advantages such as lower energy consumption, longer filter life, high filtration capacity, easier maintenance, lower weight compared to other filter media. The nanofibers based filter media made up of fibers with diameters ranging from 100 to 1000 nm were conveniently produced by electrospinning technique. Typically filter media are produced with a layer of fine fibers that can be used lonely or as a component in a media structure. The fine fiber increases the efficiency of filtration by trapping small particles which increases the overall particulate filtration efficiency of the structure. Improved fine fiber structures have been developed in this study in which a controlled amount of fine fiber is placed on both sides of the media to result in an improvement in filter efficiency and a substantial improvement in lifetime. In this research, regenerated silk fibroin obtained from industrial silk wastes and polyacrylonitrile (PAN) fibers was used to produce filter. Characteristics such as fibers diameter and its distribution, porosity and thickness of nanofiber filters obtained in lab were examined by Scanning Electron Microscopy (SEM) and analysed using image processing algorithms. Keywords: electrospinning, nanofilter, image processing, Fourier Transform, porosity

When great damages occur on gas-pipes, a quick intervention is often needed, as close to the place of damage as it can be. That is the reason why recently it has more and more been used a procedure of squeezing the pipe using a squeeze-off tool and thus stopping the flow. After the damage has been removed, the deformed pipe returns to the original shape by using re-rounding clam and the flow is established yet again. After the above-described process, the pipe is permanently deformed, as far as shape and thickness are concerned. The size of the deformation is important for the assessment of further use of the existing pipes or for determining the parameters for the newly-projected pipes. So far, the researches have been dealing with the hydrostatic and stress states after the squeezing of the pipe. The subject of this research is the decrease of the pipe thickness after the squeezing, and the goal is to help the designers of distributive plastic gas-pipes to determine the pipe wall thickness, as well as to help the managers of distributive networks so that they would know what happens to the existing gas-pipes after the intervention on the pipe. Keywords: sqeeze – off tool, polyethilene gas pipe

In the present study EP142-C510-50 woven carbon fiber composite was investigated from structural/mechanical point of view aiming manufacturing parts for aeronautical industry. The composites were obtained by hand lay-up process. Prior to mechanical tests, the cure reaction results of composite resins specimens were analyzed by using DSC technique. The EP142 epoxy matrix was cured/polymerized at 160°C. After molding, the laminates were cut into specimens for 3 points flexure, tensile and fatigue tests. The mechanical tested samples observed by scanning electron microscopy revealed their fractured and microstructure aspects. A nondestructive US method allowing elastic constant determination on a composite plate was proposed during this study. Keywords: carbon/epoxy composite material, mechanical properties, structural characterization, aeronautical industry

The options to deposit chemically a functional composite copper-diamond coatings from trilonic electrolyte have been studied with respect to the influence of the air flow stiring conditions of deposition. They have been elucidated in regard to the structure of the copper metal-matrix and the number of the co-deposited diamond particles. Optimal composition has been established as well as the best hydrodynamic regime for chemical deposition of the functional composite copper-diamond coatings (with respect to the number of the co-deposited diamond particles observed by SEM and the thickness of the composite layer) upon the addition of an appropriate surfactant compound Na-laurylsulfonate (NaLS) to the electrolyte, which is preventing the agglomeration and precipitation of the diamond particles in the electrolyte. Keywords: functional composites; coating; metal-matrix composites (MMCs); non-metallic substrate

The surface effect of nano- and microscale structures of some orthopedic materials, containing nano hydroxyapatite (HAP) and collagen type I (COL), on the interactions of osteoblasts with the surface of these materials is investigated and analyzed. The size and shape of inorganic particles are examined by TEM, SEM and AFM imaging. The surface morphology of collagen self-assemblies is also explored by AFM and SEM observations. Results show that the effect of the surface structure is significant on cell behaviour and can be correlated with cell constructs on these materials in cell culture. Keywords: orthopedic materials, surface structure, osteoblasts, TEM, SEM, AFM

The paper deals with a comparison of the surface roughness of WPC (Wood Plastic Composite) after the machining (turning). Turning was performed with constant speed rotation and constant depth of cut. The goal of this paper was the observed change of average maximum height Rz (roughness average Ra) with change of feeds (interval of feed f=0.1 to 0.61mm) and design recommendations resulting from acquired knowledge. Keywords: Wood Plastic Composite, machining, surface roughness

Polymeric fixed partial prosthesis represents an important part of the prosthetic treatment. Their presence in the oral cavity could lead to fracture them and to alter the final prosthetic treatment. Time Domain Optical Coherence Tomography can be used as a noninvasive evaluation method and 3D reconstructions which could generate a real forecast on those prosthesis in the oral cavity environment. Keywords: polymeric fixed partial prosthesis, optical coherence tomography, non invasive method, material defect

This paper refers to the preparation of durable performance concrete using superplasticizer additives. The study revealed the influence of polymer additives on the nature and concentration of physical and mechanical characteristics of concrete obtained as compared with a standard concrete (without additives). Keywords: concrete, polymeric additives, superplasticizers, lignosulfonates, ether polycarboxylates

The paper focuses on the experimental evaluation of acoustic properties of biodegradable composite materials with textile inserts used for products with a protective role in the urban habitat. The materials used in this study are obtained from mixed wood and textile waste bonded together with ecological binders. In order to determine the absorption and reflection coefficients, the samples were tested using the impedance tube Bruel & Kjaer type, 4206 A, with a frequency range between 100 - 3200 Hz. It was concluded that the tested specimens have shown a high absorption coefficient for the frequency range between 800 – 2800 Hz. It was also noticed that the values of absorption coefficient depended on the type and quantity of binders. Based on the experimental results, the composition of the tested materials will be improved in the future in order to obtain a good absorption of the sound at low frequencies. Keywords: absorption, reflection, composite, frequency, impedance tube

Engineers, biologists and surgeons face a special task when they design procedures, components and systems to replace tissues damaged beyond any limits, caused by disease or trauma. It has been proven that titanium and its alloys have an excellent biocompatibility, that’s why many studies have been made on them, in order to enhance their biomedical applicability. In this paper, the wear behavior of HEMA was analyzed, for use as a cartilage substitute , in experimental models in vivo for testing under conditions very close to reality for two new materials, Ti12Mo and Ti25Nb25Ta alloys. Keywords: titanium alloy, synovial fluid, HEMA