The effect of combined use of chitosan and PIPS on push-out bond strength of root canal filling materials

Adhesion of root canal filling materials to root dentin is important for the long-term success of the treatment. Push-out bond strength test is used to evaluate the adhesion capacity of root canal filling materials to root canal walls. The aim of the present study is to compare the bond strength of root canal filling materials to root dentin after irrigation with EDTA, chitosan and the combination of chitosan and PIPS irridation using push-out bond strength test. Forty-eight extracted teeth were resected until 13-mm long roots were obtained. Root canals were prepared with a size-25 OneShape instrument. Samples were divided into three groups each including 15 roots. Group 1: Canals were rinsed with 0.2% chitosan and subjected to laser irridation with PIPS at the same time. Group 2: Canals were rinsed with 0.2% chitosan. Group 3: Canals were rinsed with EDTA. All canals were filled with .06 tapered gutta-percha and AH-plus sealer. One-mm thick slices were taken from coronal, middle and apical one-thirds of the roots. Push-out bond strength was determined using a Universal Testing Machine. One root from each group was observed under SEM to evaluate the degree of smear removal. Statistical analysis was performed with Kruskall-Wallis test. Results showed that bond strength values were statistically similar in overall evaluation for all groups (p > .05). In segmental evaluation, group 1 revealed the highest bond strength in apical one-third compared to other groups (p < .05).     

Solar assisted multi-generation system using nanofluids: A comparative analysis

In this comparative study, a parabolic trough solar collector and a parabolic dish solar collector integrated separately with a Rankine cycle and an electrolyzer are analyzed for power as well as hydrogen production. The absorption fluids used in the solar collectors are Al₂O₃ and Fe₂O₃ based nanofluids and molten salts of LiCl–RbCl and NaNO₃–KNO₃. The ambient temperature, inlet temperature, solar irradiance and percentage of nanoparticles are varied to investigate their effects on heat rate and net power produced, the outlet temperature of the solar receiver, overall energy and exergy efficiencies and the rate of hydrogen produced. The results obtained show that the net power produced by the parabolic dish assisted thermal power plant is higher (2.48 kW–8.17 kW) in comparison to parabolic trough (1 kW–6.23 kW). It is observed that both aluminum oxide (Al₂O₃) and ferric oxide (Fe₂O₃) based nanofluids have better overall performance and generate higher net power as compared to the molten salts. An increase in inlet temperature is observed to decrease the hydrogen production rate. The rate of hydrogen production is found to be higher using nanofluids as solar absorbers. The hydrogen production rate for parabolic dish thermal power plant and parabolic trough thermal power plant varies from 0.0098 g/s to 0.0322 g/s and from 0.00395 g/s to 0.02454 g/s, respectively.     

Further Increase of T c in Y-Ba-Cu-O Superconductors

This paper presents the synthesis and characterization of three new Y-based high temperature-superconducting compounds having relatively higher transition temperature T _c compared with that of the Y-123, Y-124, and Y-247. The electrical resistivity measurements indicate the onset critical temperatures as high as 98 K. Atomic compositions of these new Y-Ba-Cu-O superconductors are Y₂Ba₃Cu_5.2O _x , Y₂Ba₅Cu₉O _x , and YBa₄Cu₅O _x . The X-ray analysis has shown that they have a similar crystalline structure as Y-123 phases.     

Towards Further Improvements of the Magnetization Parameters of B2O3-Doped BaFe12O19 Particles: Etching with Hydrochloric Acid

In the present study, we investigate influence of HCl-etching on magnetic parameters of B₂O₃-doped M-type barium ferrites. Our studies have shown that magnetization parameters; the remanence magnetization M _r and the specific magnetization M _s at 1.5?T, increase significantly with HCl-etching. The best magnetic parameters were observed in the sample of 0.1?wt% B₂O₃-doped and HCl-washed one after calcination at 1000?°C (M _r =34.9?emu/g, M _s =0.63.3?emu/g). Increments up to 50% in magnitudes could be achieved with HCl washing. Exchange interactions between particles were also examined by Wohlfarth model. It was observed that magnetizing-like interactions between particles become stronger but ,on the other hand, demagnetizing-like interactions becomes weaker with HCl-etching.     

Consistency management in Deno

We describe a new replicatedobject protocol designed for use in mobile and weaklyconnected environments. The protocol differs from previous protocols in combining epidemic information propagation with voting, and in using fixed perobject currencies for voting. The advantage of epidemic protocols is that data movement only requires pairwise communication. Hence, there is no need for a majority quorum to be available and simultaneously connected at any single time. The protocols increase availability by using voting, rather than primarycopy or primarycommit schemes. Finally, the use of perobject currencies allows voting to take place in an entirely decentralized fashion, without any server having complete knowledge of group membership. We show that currency allocation can be used to implement diverse policies. For example, uniform currency distributions emulate traditional voting schemes, while allocating all currency to a single server emulates a primarycopy scheme. We present simulation results showing both schemes, as well as the performance advantages of using currency proxies to temporarily reallocate currency during planned disconnections. Furthermore, we discuss an initial design of the underlying replicatedobject system and present a basic API.     

Structural characterization of basalt-based glass–ceramic coatings

There are a lot of technologically interesting characteristics of glass–ceramics, which are hard, wear resistant, oxidation and corrosion resistant ceramic materials. In the present study, the production of the basalt-based glass–ceramic coating by atmospheric plasma spray technique and their structural characterization were reported. Basalt-based glass coating was performed on AISI 1040 steel substrate which was pre-coated with Ni–5 wt% Al by using plasma spray gun. Basalt coatings of the glass form were crystallized at 800, 900 and 1000 °C for 1–4 h in orders to transform to the glass–ceramic structure. The presence of augite [(CaFeMg)SiO₃], diopside [Ca(Mg_0.15Fe_0.85)(SiO₃)₂] and aluminian diopside [Ca(Mg,Al)(Si,Al)₂O₆] crystalline phases formed in the basalt-based glass–ceramic coating layer was detected by X-ray diffraction analysis. Optical microscopy with micrometer was used for metallographic examinations. Differential scanning calorimeter was used for determining the crystallization temperature of glass form basalt-based coatings. Microhardness measurements were carried out on the basalt-based glass–ceramic coating layer with Vickers indenter. The hardness of coating layers is changing between 1009 and 1295 HV_0.05 depending on crystallization temperature and process times. It was found that, the higher the crystallization temperature, the more the crystalline phases were resulted. In addition, the lower the crystallization temperature and the longer the treatment time, the harder the coating layer became.     

On labeling in graph visualization

When visualizing graphs, it is essential to communicate the meaning of each graph object via text or graphical labels. Automatic placement of labels in a graph is an NP-Hard problem, for which efficient heuristic solutions have been recently developed. In this paper, we describe a general framework for modeling, drawing, editing, and automatic placement of labels respecting user constraints. In addition, we present the interface and the basic engine of the Graph Editor Toolkit - a family of portable graph visualization libraries designed for integration into graphical user interface application programs. This toolkit produces a high quality automated placement of labels in a graph using our framework. A brief survey of automatic label placement algorithms is also presented. Finally we describe extensions to certain existing automatic label placement algorithms, allowing their integration into this visualization tool.     

Formation of chromium nitride layers on AISI 1010 steel by nitro-chromizing treatment

In this study, chromium nitride coating was realized on AISI 1010 steels by nitro-chromizing treatment. Steel samples were tufftrided at 575 °C for 2 h in the first step of the coating process, and then chromized by pack method in the powder mixture consisting of ferro-chromium, ammonium chloride and alumina at 1000 °C for 1-4 h. Samples were characterized by scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy, X-ray diffraction (XRD) analysis and Vickers micro-hardness tests. Coating layer formed on the steel samples is smooth and compact and well bonded to the steel matrix. The thickness of chromium nitride layer formed on the steel samples ranged from 5.16±1.48 to 13.45±1.73 μm, depending on the treatment time. The average micro-hardness value of the layer was 1789±59 HV_0.05. The layer consisted of Cr₂N and (Cr,Fe)₂N_(1−x) phases, according to XRD. EDS results showed that coating layer includes chromium and nitrogen.     

Compact low voltage high-Q CMOS active inductor suitable for RF applications

A compact active inductor circuit is proposed. The circuit is based on the gyrator-C approach with both transconductance stages realized by MOS transistors in common-source configuration. The circuit has minimal number of transistors, is suitable for low voltage operation, offers a wide inductive band, high quality factor and low power dissipation. Simulation results are provided for a 0.13 μm CMOS process with 1.2 V supply voltage.