Improved wear properties of magnesium matrix composite with the addition of fullerene using semi powder metallurgy

The present study aims to fabricate fullerene (C60) reinforced magnesium matrix composite via semi powder metallurgy in hot press system under high purity argon atmosphere. Improvement of wear resistance of pure magnesium with the addition of fullerene is also aimed with this study. Hardness and wear tests at room temperature were performed to investigate the mechanical effect of fullerene nanoparticles. Microstructures of fabricated composites were characterized using Scanning Electron Microscope (SEM). Results clearly show that hardness performance was improved up to 0.5 wt. % fullerene addition directly. A uniform distribution was also achieved according to the mapping and line EDX analysis for the lower content of fullerene. Agglomeration of fullerene was observed for 1 wt. % reinforced composite. Wear performances of pure magnesium were also improved when harder fullerene reinforcements incorporated into the matrix. Abrasion and oxidation were main wear mechanism for unreinforced and fullerene reinforced composites. Enhancement of hardness and wear performances might be attributed to the high specific surface area of fullerene and achievement of uniform distribution of reinforcement in magnesium matrix.     

Utilisation of waste clay from boron production as a landfill liner material

The objective of this study was to investigate the potential utilisation of waste clay from boron production in sanitary landfills. The waste clay (CW) was mixed with bentonite (B) and waste tyre (TW) at different ratios. Results show that, any of the CW-TW mixtures were not acceptable to use in landfills because of insufficient bearing capacity values. On the other hand, CW and 2B/98CW mixtures have sufficient values from the point of experimental tests. As a conclusion, it has been concluded that CW can be used as a liner material for landfills without an addition.     

A Theory of Network Localization

In this paper, we provide a theoretical foundation for the problem of network localization in which some nodes know their locations and other nodes determine their locations by measuring the distances to their neighbors. We construct grounded graphs to model network localization and apply graph rigidity theory to test the conditions for unique localizability and to construct uniquely localizable networks. We further study the computational complexity of network localization and investigate a subclass of grounded graphs where localization can be computed efficiently. We conclude with a discussion of localization in sensor networks where the sensors are placed randomly     

Complications of 1303 central venous cannulations

Central venous catheterization (CVC), now a common procedure, has several major complications. We assessed their incidence in a prospective study of 1303 cannulations done in the intensive care unit or operating theatre. Chest radiographs were obtained to verify proper catheter placement and to detect pneumothorax. Complications were arterial puncture in 68 (5.2%) patients, arrhythmias in 21 (1.6%), cardiopulmonary arrest in 1 (0.1%), and pneumothorax in 5 (0.5%). The tip of the CVC was incorrectly located in 149 (11.2%). The chest radiograph was a valuable method for detecting complications of central venous catheterization.     

Frequency and focal region properties of random sparse arrays

The concept of a random array relay, in terms of a sparse array, is introduced. The basic idea is to replace the relatively compact radiating structures encountered in conventional communication systems with widely and randomly dispersed radiating systems. The frequency and focal region properties of such random sparse arrays are treated. A methodology for obtaining the expected frequency response, focal region contours and depth of field for any random sparse array is given. The technique is exemplified with results for spherical and spherical-shell arrays. In addition, computer simulation results for sample functions of frequency responses and focal region contours are presented, both to verify the theoretical results and to illustrate some of the salient properties of random sparse arrays.     

Coset networks as connectors in parallel processors

An active area of research regarding parallel computer systems deals with the design of interconnection networks. Among all interconnection networks, permutation networks play a special role as all other networks can be constructed using such networks. It was recently shown that many permutation networks reported in the literature are manifestations of coset decompositions of symmetric groups. This result is generalized here to obtain several other previously unknown permutation networks which satisfy such decompositions. In addition, analyses of the edge-count, propagation delay, fan-out, and setup time of such networks are provided. The results lead to some anomolous behavior as well as several trade-offs among these parameters. For example, it is shown that a complete bipartite graph is the fastest and most economical direct realization of a permutation network. Furthermore, it is shown that the fan-out of a network is inversely proportional to the propagation delay whereas the setup time may or may not relate to the propagation delay at all depending on the network in question. Finally, two constant fan-out implementations of these networks using O (n ^1.59) 2 × 1 multiplexers and 2 × 2 switches are presented.This work is supported in part by the National Science Foundation under Grant No: CCR-8708864.     

A randomized comparison of the 3 Papanicolaou smear collection methods

The purpose of this study was to compare the effectiveness of 3 cervical smear sampling devices for obtaining acceptable yields of endocervical cells in Papanicolaou smears. In a randomized, controlled clinical trial, we collected 346 smears over a 6-month period, 110 with the Cervex brush, 125 with the cotton swab plus Ayre spatula and 111 with the Cytobrush plus Ayre spatula. The Cytopathology Laboratory, blinded to the Papanicolaou smear method, screened the smears using the Bethesda system guidelines. Statistical analyses were performed using the Pearson X2 and analysis of variance tests. There was an increased detection of endocervical cells in the Cytobrush plus Ayre spatula and the Cervex brush methods, compared with the cotton swab plus Ayre spatula group (p = 2.39 x 10(-6), p = 4.49 x 10(-7) respectively). There was no statistically significant difference between the Cytobrush-Ayre spatula and the Cervex brush sampling methods were equally effective in obtaining endocervical cells in Papanicolaou smears.     

Status of the tick-borne diseases in sheep and goats in Turkey

A patient treatment is presented to demonstrate a technique using visible-light-cured (VLC) resin to create a characterized denture base for an interim denture. This indication for characterization is routinely seen with African-Americans with dark-pigmented gingiva. Using a combination of blue VLC tray resin and pink VLC denture base resin, the mixture achieves a darker-colored denture base. This technique was used for the fabrication of an interim denture for a patient who required an immediate interim denture. The prosthesis was worn during the healing phase and allowed the patient to function while the definitive prosthesis was being fabricated.     

Synthesis of phosphorus‐ and phenyl‐based ROMP polymers and investigation of their effects on the thermomechanical and flammability properties of a polypropylene–IFR system

In this study, we present an approach for the synthesis of novel phosphorous‐ or phenyl‐ containing polymers, 2_phenyl, 3_phospho, and 2_phenyl‐co‐3_phospho, derived from ring‐opening metathesis polymerization (ROMP), to reduce the flammability of polypropylene (PP). The composites were processed by melt‐blending ROMP polymers and octaphenyl–polyhedral oligomeric silsesquioxane with PP/intumescent flame retardant (IFR) compounds at different compositions. The composites were characterized by limiting oxygen index (LOI), UL‐94, and mechanical tests as well as thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The molecular structures of phosphorous‐ and phenyl‐containing polymers were proved by ¹H‐NMR, ¹³C‐NMR, and Fourier transform infrared spectroscopy. The online rheological measurements indicated that the addition of additives to the PP/IFR system increased the melt viscosity of the compounds regardless of the type. The DSC analysis showed that the addition of ROMP polymers to the PP/IFR system influenced the crystal perfection and degree of crystallization. TGA analysis of the composites revealed that the addition of ROMP polymers to PP/IFR compounds deteriorated the thermal stability as the amount of phosphorus increased in the matrix. Dynamic mechanical properties such as storage modulus (E′) and loss modulus (E″) of the composites were lowered by the addition of ROMP polymers. The LOI and UL‐94 rating of PP/IFR were enhanced by the addition of ROMP polymers. It was successfully demonstrated that the novel phosphorous‐ or phenyl‐containing polymers were highly potent additives in optimizing the flammability of PP composites. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45998.