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Number of results: 9
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Abstract

Clean and cheap device, namely dye-sensitized solar cells (DSSCs) were fabricated using a natural dye extracted from Sambucus ebulus. We prepared five sample solutions with various pH in the extraction process to improve power conversion efficiency. The UV–visible absorption investigation of sample solutions and on photoanode show the dyes from J-type aggregation on a photoanode substrate. Redox properties of all sample solutions certify thermodynamically a charge transfer from excited state to conduction band TiO2. The optical properties of various dye solutions were investigated and results showed darkness and bluish tint effect of dye solutions extracted in basic environment rather than those extracted in acidic condition. Moreover, in comparison to the basic condition, the dye solutions extracted in acidic environment were more saturated and colorimetrically less different from that one which extracted in neutral condition. Photophysical and photoelectrochemical performance of natural extraction dyes have been studied in dye-sensitized solar cell devices. The results show the rather high conversion efficiency of 0.57%, 1.15%, 1.02%, 0.35% and 0.15% of each individual dye extraction, respectively.

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Authors and Affiliations

M. Hosseinnezhad
R. Jafari
K. Gharanjig
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Abstract

Photoelectrical characteristics of scanning IR detectors with implemented time delay and integration mode are analyzed. A new “shifted cellular” layout of photosensitive elements in the FPA structure is proposed. Advantages of the new FPA configuration in terms of threshold sensitivity for small-size/point objects are demonstrated. The analysis is based on the Monte Carlo simulation of the diffusion process of photogenerated minority charge carriers in the photosensitive layer photodiode arrays. The analysis is performed taking into account the main photoelectric parameters of FPA elements: photosensitive layer thickness, diffusion length of charge carriers, optical absorption length, their design parameters: geometric sizes of FPA elements, diameters of p-n junctions, and design parameters of the optical system: optical-spot diameter.

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Authors and Affiliations

S. A. Dvoretsky
A. P. Kovchavtsev
I. I. Lee
V. G. Polovinkin
G. Yu. Sidorov
M. V. Yakushev
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Abstract

This work presents concepts of the use of algorithms inspired by the functions and properties of the nervous system in dense wireless networks. In particular, selected features of the brain consisting of a large number of nerve connections were analyzed, which is why they are a good model for a dense network. In addition, the action of a selected cells from the nervous system (such as neuron, microglia or astrocyte) as well as phenomena observed in it (e.g. neuroplasticity) are presented.

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Authors and Affiliations

Łukasz Kułacz
Adrian Kliks
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Abstract

The paper presents the results of research on the kinetics of the binding process of self-hardening moulding sands with an organic binder under conditions of forced air flow at various pressure values. Three moulding sands made using urea-furfuryl resin Furanol FR75A technology were studied. The moulding sands were prepared on a base of quartz sand with an average grain size of dL = 0.25, 0.29 and and 0.37 mm , with permeability values of 306 , 391 and and 476 m 2/10 8Pa ∙ s (for ρ0 = 1.60 , 1.60 and and 1.61 g/cm 3, respectively). The research was conducted for a resin content of 1% with a constant proportion of hardener to resin, which was equal to 50%. Samples of the tested moulding sands were blown with air at pressures of 0.1, 0.2, 0.4, 0.6, 0.8, and 1.0 bar. The kinetics of the hardening process was monitored using ultrasound technology, according to a previously developed methodology [1]. The research was carried out on an ultrasound testing station equipped with a temperature chamber and an airflow reducer. The tests were conducted at a temperature of 20°C, and of the air flow pressure on the changes in ultrasonic wave velocity in the hardening mouldins sand as a function of time, the kinetics of the hardening process, and the degree of moulding sand hardening were determined. Additionally, the influence of the moulding sand permeability on the course of the hardening process at a constant air flow pressure was determined.
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Bibliography

[1] Zych, J. (2007). Synthesis of the applications of ultrasonic technology in the analysis of the kinetics of selected processes occurring in molding materials. AGH Uczelniane Wydawnictwa Naukowo-Dydaktyczne. Seria: Rozprawy i Monografie nr 163, Kraków. (in Polish).
[2] Holtzer, M., Kmita, A. & Roczniak, A. (2014). New furfuryl resins more environmentally friendly. Archives of Foundry Engineering. 14(spec.4), 51-54. (in Polish).
[3] Lewandowski, J.L. (1997). Materials for casting molds. Kraków: Wydawnictwo Akapit. (in Polish).
[4] Lewandowski, J.L (1971). Molding materials. Warszawa: Wydawnictwo Naukowe PWN. (in Polish).
[5] Dobosz, St.M. (2006). Water in molding and core sands. Kraków: Wydawnictwo Akapit. (in Polish).
[6] Drożyński, D. (1999). Post-surface phenomena in the process of binding masses in the classic cold-box technology. Unpublished doctoral dissertation, AGH Univesity of Science and Technology, Kraków. (in Polish).
[7] Lewandowski, J.L. (1991). Molding and core sands. Warszawa: Wydawnictwo Naukowe PWN. (in Polish).
[8] Jamrozowicz, Ł., Kolczyk, J. & Kaźnicva, N. (2016). Study of the hardening kinetics of self-hardening masses at low temperature. Prace Instytutu Odlewnictwa. LVI, 4/2016, 379-390. (in Polish).
[9] Matonis, N. & Zych, J. (2022). Plasticity changes of moulding sands with chemical binders caused by increasing the hardenin degree. Archives od Foundry Engineering. 22(2), 71-76. DOI: 10.24425/afe.2022.140227.
[10] Zych, J. (1999). Patent Nr PL 192202 B1. Kraków
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Authors and Affiliations

Natalia Matonis
1
ORCID: ORCID

  1. AGH University of Science and Technology, Faculty of Foundry Engineering, Poland
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Abstract

The temperature dependence of the particle size distribution (PSD) of the magnetic fluid with an additional biocompatible dextran layer was studied using a ultrasonic method. The measurements of the ultrasound velocity and attenuation were carried out as a function of the volume concentration of magnetite particles at temperatures ranging from 15°C to 40°C. In order to extract the PSD from ultrasonic measurements, the theoretical model of Vinogradov-Isakovich was used. The extraction of PSD from the ultrasonic data requires also the measurements the density and viscosity of the ferrofluid samples. The calculated PSD of the magnetic fluid with an additional biocompatible layer shows a greater thermal stability than that of a magnetic fluid with a single surfactant layer.
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Authors and Affiliations

Leszek Dąbek
Tomasz Hornowski
Arkadiusz Józefczak
Andrzej Skumiel
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Abstract

Intensive surveys conducted at Samaru and its environs in the northern Guinea Savanna of Nigeria between October 2000 and September 2002, indicated that Bemisia tabaci (Genn.) infests forty two (thirty three cultivated and seven wild) species of plants. Twenty nine of the plants were found in upland, two in the lowland and eleven in both upland and lowland (fadama) areas. Heavily infested plants were distorted, chlorotic and stunted. Symptoms of virus infection were associated with some of the infested plants. This is the first comprehensive report of hosts of B. tabaci in Nigeria.

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Authors and Affiliations

Matthew D. Alegbejo
Olalekan O. Banwo
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Abstract

The paper presents the results of an investigation of the thermal deformation of moulding sands with an inorganic (geopolymer) binder with a relaxation additive, whose main task is to reduce the final (residual) strength and improves knocking-out properties of moulding sand. The moulding sand without a relaxation additive was the reference point. The research was carried out using the hot-distortion method (DMA apparatus from Multiserw-Morek). The results were combined with linear deformation studies with determination of the linear expansion factor (Netzsch DIL 402C dilatometer). The study showed that the introduction of relaxation additive has a positive effect on the thermal stability of moulding sand by limiting the measured deformation value, in relation to the moulding sand without additive. In addition, a relaxation additive slightly changes the course of the dilatometric curve. Change in the linear dimension of the moulding sand sample with the relaxation additive differs by only 0.05%, in comparison to the moulding sand without additive.

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Authors and Affiliations

A. Bobrowski
D. Drożyński
J. Jakubski
M. Szumera
K. Kaczmarska
B. Grabowska

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