Sliding Performance of PEI Composites Under Dry Atmospheric Conditions

In this work, the dry sliding wear behavior of PEI+15%PTFE and PEI+20%GFR polymer composites rubbing against PPS+40%SGFR, BMC+15%LGFR and stainless steel were investigated using a pin–on– disc arrangement. Test conditions were 20 to 60N loads and at 0.5 m/s sliding speeds. It was observed that, the specific wear rate showed very little sensitivity to the varying load. For all material combinations used in this investigation, the coefficient of friction decreases linearly with the increase in load. The specific wear rate decreases with the increase in applied load for polymer-polymer combinations but increases or shows no change with the increase in load value for polymer- steel disc combinations. Finally it is concluded that the wear resistance of 15% PTFE filled PEI composite is higher than that of 20% glass fibre reinforced poly-ether-imide polymer composite against different polymer and steel counter-faces. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3526

Nanoplasmonic surfaces enabling strong surface-normal electric field enhancement

Cataloged from PDF version of article.Conventional two-dimensional (2D) plasmonic arrays provide electric field intensity enhancement in the plane, typically with a surface coverage around 50% in the plan-view. Here, we show nanoplasmonic three-dimensional (3D) surfaces with 100% surface coverage enabling strong surface-normal field enhancement. Experimental measurements are found to agree well with the full electromagnetic solution. Along with the surface-normal localization when using the plasmonic 3D-surface, observed maximum field enhancement is 7.2-fold stronger in the 3D-surface than that of the 2D counterpart structure. 3D-plasmonic nonplanar surfaces provide the ability to generate volumetric field enhancement, possibly useful for enhanced plasmonic coupling and interactions. © 2013 Optical Society of America

ODFNet: Using orientation distribution functions to characterize 3D point clouds

Learning new representations of 3D point clouds is an active research area in 3D vision, as the order-invariant point cloud structure still presents challenges to the design of neural network architectures. Recent works explored learning either global or local features or both for point clouds, however none of the earlier methods focused on capturing contextual shape information by analysing local orientation distribution of points. In this paper, we leverage on point orientation distributions around a point in order to obtain an expressive local neighborhood representation for point clouds. We achieve this by dividing the spherical neighborhood of a given point into predefined cone volumes, and statistics inside each volume are used as point features. In this way, a local patch can be represented by not only the selected point's nearest neighbors, but also considering a point density distribution defined along multiple orientations around the point. We are then able to construct an orientation distribution function (ODF) neural network that involves an ODFBlock which relies on mlp (multi-layer perceptron) layers. The new ODFNet model achieves state-of the-art accuracy for object classification on ModelNet40 and ScanObjectNN datasets, and segmentation on ShapeNet S3DIS datasets.Comment: The paper is under consideration at Computer Vision and Image Understandin

On-chip integrated nanowire device platform with controllable nanogap for manipulation, capturing, and electrical characterization of nanoparticles

Cataloged from PDF version of article.We propose and demonstrate nanowire (NW) device platforms on-chip integrated using electric-field-assisted self-assembly. This platform integrates from nanoprobes to microprobes, and conveniently allows for on-chip manipulation, capturing, and electrical characterization of nanoparticles (NPs). Synthesizing segmented (Au–Ag–Au) NWs and aligning them across predefined microelectrode arrays under ac electric field, we controllably form nanogaps between the self-aligned end (Au) segments by selectively removing the middle (Ag) segments. We precisely control and tune the size of this middle section for nanogap formation in the synthesis process. Using electric field across nanogaps between these nanoprobes, we capture NPs to electrically address and probe them at the nanoscale. This approach holds great promise for the construction of single NP devices with electrical nanoprobe contacts

Osteoselection supported by phase separeted polymer blend films

Cataloged from PDF version of article.The instability of implants after placement inside the body is one of the main obstacles to clinically succeed in periodontal and orthopedic applications. Adherence of fibroblasts instead of osteoblasts to implant surfaces usually results in formation of scar tissue and loss of the implant. Thus, selective bioadhesivity of osteoblasts is a desired characteristic for implant materials. In this study, we developed osteoselective and biofriendly polymeric thin films fabricated with a simple phase separation method using either homopolymers or various blends of homopolymers and copolymers. As adhesive and proliferative features of cells are highly dependent on the physicochemical properties of the surfaces, substrates with distinct chemical heterogeneity, wettability, and surface topography were developed and assessed for their osteoselective characteristics. Surface characterizations of the fabricated polymer thin films were performed with optical microscopy and SEM, their wettabilities were determined by contact angle measurements, and their surface roughness was measured by profilometry. Long-term adhesion behaviors of cells to polymer thin films were determined by F-actin staining of Saos-2 osteoblasts, and human gingival fibroblasts, HGFs, and their morphologies were observed by SEM imaging. The biocompatibility of the surfaces was also examined through cell viability assay. Our results showed that heterogeneous polypropylene polyethylene/polystyrene surfaces can govern Saos-2 and HGF attachment and organization. Selective adhesion of Saos-2 osteoblasts and inhibited adhesion of HGF cells were achieved on micro-structured and hydrophobic surfaces. This work paves the way for better control of cellular behaviors for adjustment of cell material interactions. © 2014 Wiley Periodicals, Inc

Utjecaj lucerne i koncentriranih krmiva na razinu kolesterola i sastav masnih kiselina u serumu i iznutricama janjadi

This study was conducted to investigate the effects of fresh, ensiled and dried alfalfa on the fatty acid composition and cholesterol level of the serum, liver, kidney and spleen samples in yearling sheep. Forty Akkaraman lambs, 4 months of age, with an average body weight of 21 kg were used in the study. All diets were formulated to be isonitrogenous and isoenergetic. The lambs were divided into four groups according to feed: wheat straw as roughage (Control group, C); fresh alfalfa as roughage (AF group); ensiled alfalfa (AS group); and dried alfalfa (AD group). The alfalfa group had lower saturated fatty acid (SFA) and higher polyunsaturated fatty acid (PUFA) contents than the wheat straw group. In parallel, SFA concentrations in the serum and offal (liver, kidney and spleen) were signifi cantly higher in the controls, whereas the highest PUFA amounts were recorded in lambs fed with fresh alfalfa. Serum and offal proportions of ω3 and ω6 fatty acids significantly increased except in serum ω3 content of lambs fed with alfalfa. However, the cholesterol level decreased in all groups given alfalfa. In conclusion, the results of this study suggest that alfalfa consumption causes a significant decrease in cholesterol levels and a significant increase in PUFA levels in lambs. Additionally, it may be said that the risk of coronary heart diseases may decrease in humans who consume the offal of lambs fed with alfalfa.U radu su istraženi učinci svježe, silirane i sušene lucerne na sastav masnih kiselina i razinu kolesterola u serumu te u uzorcima jetre, bubrega i slezene jednogodišnjih ovaca. U istraživanju je korišteno 40 janjadi akaraman pasmine, u dobi od 4 mjeseca, prosječne tjelesne mase od 21 kg. Obroci su bili ujednačeni s obzirom na sadržaj dušika i energije. S obzirom na upotrijebljenu krmu janjad je bila podijeljena u četiri skupine: kontrolna skupina je dobivala pšeničnu slamu, skupina AF je dobivala svježu lucernu, skupina AS siliranu lucernu te skupina AD sušenu lucernu. Lucerna je sadržavala manje zasićenih masnih kiselina (SFA) i više polinezasićenih masnih kiselina (PUFA) u odnosu na pšeničnu slamu. Usporedno, koncentracije SFA u serumu i iznutricama (jetrima, bubregu i slezeni) bile su značajno više u kontrolnoj skupini, dok su najviše koncentracije PUFA zabilježene u janjadi hranjene svježom lucernom. Omjer ω3 i ω6 masnih kiselina bio je značajno povišen, osim koncentracije ω3 u serumu janjadi hranjene lucernom. Međutim, razina kolesterola bila je snižena u svim skupinama hranjenim lucernom. Zaključno, rezultati ovoga istraživanja upućuju da hranidba lucernom dovodi do značajnoga sniženja razine kolesterola i značajnoga povišenja razine PUFA u janjadi. Dodatno bi se moglo reći da je u osoba koje konzumiraju iznutrice janjadi hranjene lucernom smanjen rizik od bolesti srca i krvnih žila

Effects of dietary fish oil and flax seed on cholesterol and fatty acid composition of egg yolk and blood parameters of laying hens

This study was conducted to determine the effects of the supplementation of different levels of fish oil (FO) and flax seed (FS) in the diets of layers on the content of egg yolk fatty acid, cholesterol, blood parameters, egg production and egg quality criteria. In the experiment, a total of 120 Isa-White laying hens of 34 weeks of age were used. Hens were divided randomly into five groups and fed different diets containing no FO and FS; 1.5% FO; 4.32% FS; 1.5% FO+4.32% FS and 8.64% FS for eight weeks. A significant decrease in yolk cholesterol content (mg/g yolk) was found in the eggs from hens fed the diets containing 1.5 % FO and 8.64% FS as compared with the control. Adding FO and FS to diets significantly increased the total omega-3 fatty acids in eggs at 28 (phase 1) and 56 (phase 2) days of the trial. By contrast, the addition of both FO and FS to diets had no effect on total omega-6 fatty acids in eggs in phase 1. But dietary 1.5% FO, 4.32% FS and 1.5% FO+4.32% FS supplementation decreased significantly the total omega-6 fatty acids compared to the controls in phase 2. The linolenic acid content of eggs was the highest in eggs from hens fed the diet with added FS, while docosahexaenoic acid content was the highest in eggs from hens fed diets with added FO. Dietary supplementation of FO and FS did not significantly affect the concentrations of serum trigliceride and high density lipoprotein. The serum cholesterol level of hens fed diets containing 1.5% FO+4.32% FS and 8.64% FS was lower than the control group. The addition of FO and FS to diets did not cause any negative effect on some egg quality criteria such as egg weight, yolk weight, yolk ratio, albumen weight, albumen ratio, shell weight, shell ratio, shell strength and shell thickness. The egg production of hens fed a diet containing 4.32% FS was significantly higher than the controls. Feed intake and feed conversion were not affected by all treatments. Keywords: Omega-3 fatty acids, Cholesterol eggs, Flax seed, Fish oil South African Journal of Animal Science Vol.33(4) 2003: 266-27

Semi-Automatic 3-D Segmentation of Anatomical Structures of Brain MRI Volumes using Graph Cuts

We present a semi-automatic segmentation technique of the anatomical structures of the brain: cerebrum, cerebellum, and brain stem. The method uses graph cuts segmentation with an anatomic template for initialization. First, a skull stripping procedure is applied to remove non-brain tissues. Then, the segmentation is done hierarchically by first, extracting first the cerebrum from the brain, and then from the remaining volume the cerebellum and the brain stem are separated. This method is fast and can separate different anatomical structures of the brain in spite of weak boundaries. We describe our approach and present experimental results demonstrating its usefulness

Comparison of PI Controllers Designed for the Delay Model of TCP/AQM Networks

Cataloged from PDF version of article.One of the major problems of communication networks is congestion. In order to address this problem in TCP/IP networks, Active Queue Management (AQM) scheme is recommended. AQM aims to minimize the congestion by regulating the average queue size at the routers. To improve upon AQM, recently, several feedback control approaches were proposed. Among these approaches, PI controllers are gaining attention because of their simplicity and ease of implementation. In this paper, by utilizing the fluid-flow model of TCP networks, we study the PI controllers designed for TCP/AQM. We compare these controllers by first analyzing their robustness and fragility. Then, we implement these controllers in ns-2 platform and conduct simulation experiments to compare their performances in terms of queue length. Taken together, our results provide a guideline for choosing a PI controller for AQM given specific performance requirements. (C) 2013 Elsevier B.V. All rights reserved