Search results for " engineering"
showing 10 items of 38291 documents
Patterning of supported gold monolayers via chemical lift-off lithography
2017
The supported monolayer of Au that accompanies alkanethiolate molecules removed by polymer stamps during chemical lift-off lithography is a scarcely studied hybrid material. We show that these Au–alkanethiolate layers on poly(dimethylsiloxane) (PDMS) are transparent, functional, hybrid interfaces that can be patterned over nanometer, micrometer, and millimeter length scales. Unlike other ultrathin Au films and nanoparticles, lifted-off Au–alkanethiolate thin films lack a measurable optical signature. We therefore devised fabrication, characterization, and simulation strategies by which to interrogate the nanoscale structure, chemical functionality, stoichiometry, and spectral signature of t…
Ecology of Vastedda della valle del Belìce cheeses: A review and recent findings to stabilize the traditional production
2018
The increasing request for classic foods has led to a higher demand for cheeses enjoying a “recognition of quality” status. This phenomenon has also affected Sicilian dairy products, in particular protected designation of origin (PDO) “Vastedda della valle del Belìce” (VdB), a cheese traditionally available only during the summer season, but requested year round. The variations of the microbial populations of raw milk among the seasons influence the microbiological quality of the cheeses produced. This review article reports the historical importance of cheeses and the traditional equipment used for dairy productions in Sicily with a specific focus on VdB. The microbial ecology of this chee…
Electrooxidation of diesel fuel in alkaline electrolyte
2016
In recent decades the demand of energy has increased significantly.Providing more and more energy is an essential task of today’s energetic industry. In the last few years, addition to traditional methods of energy production, alternative energy sources have been developing fast.One of these sources is fuel cell, mainly due to their high efficiency. Generally fuel cells are powered by hydrogen. However, problems with the storage of hydrogen are the reason for the search of new fuels for fuel cells. Moreover, fuel cells can provide an additional/emergency electricity source in energy systems using combustion engines. So, it is important using the main fuel for powering the fuel cell. One of …
Prompt Determination of the Mechanical Properties of Industrial Polypropylene Sandwich Pipes
2021
A simple and prompt method to determine the mechanical properties of industrial multilayer extrusion polypropylene pipes for a gravity sewer network is suggested. The engineering formulas included for calculating the permissible thickness and relative position of a foam core in the pipes are based on a linear-elastic approximation and the rule of mixtures. The applicability of the approximation was justified experimentally during investigation of the effective tensile characteristics of single- and multilayer pipes and each layer specimen by using traditional tests and finite-element calculations. The results obtained were used to formulate engineering recommendations for calculations of th…
Nanofilm Low Cost Oxygen Sensors
2009
Abstract The resitivity change of ultra thin metals under air exposure is used for vacuum or inert gas packaging control. In order to reach low cost, single use applications, few nm thin Aluminum layers were deposited on PET substrates and combined with wireless electronic readout circuitry. The sensor respose is characterized by resistance changes and explained in terms of multiphase diffusion mechanisms which are very sensitive to technological parameters.
Compensation of Nonlinearity of Voltage and Current Instrument Transformers
2019
This paper aims at characterizing and improving the metrological performances of current and voltage instrument transformers (CTs and VTs) in harmonic measurements in the power system. A theoretical analysis is carried out to demonstrate that, due to the iron core nonlinearity, CT and VT output signal is distorted even when the input signal is a pure sine wave. Starting from this analysis, a new method for CT and VT characterization and compensation is proposed. In a first step, they are characterized in sinusoidal conditions and the harmonic phasors of the distorted output are measured; in the second step, these phasors are used to compensate the harmonic phasors measured in normal operati…
Deconstruction and hermeneutical space as keys to understanding the rural
2020
The purpose of this article is to complement the existing literature on defining the rural by suggesting a novel approach that makes possible a holistic understanding of the rural. The proposed approach is based on deconstruction of the concept of the rural and on hermeneutical philosophy. The current approaches applied in rural studies are evaluated through the lens of holistic understanding, and solutions to the observed problems are discussed. The problems of current rural studies stem from inadequate conceptualization and biased social theory. The conceptual problems can be alleviated, firstly, by understanding the concept of space not only literally but also figuratively. Secondly, the…
A Computationally Efficient Online/Offline Signature Scheme for Underwater Wireless Sensor Networks
2022
Underwater wireless sensor networks (UWSNs) have emerged as the most widely used wireless network infrastructure in many applications. Sensing nodes are frequently deployed in hostile aquatic environments in order to collect data on resources that are severely limited in terms of transmission time and bandwidth. Since underwater information is very sensitive and unique, the authentication of users is very important to access the data and information. UWSNs have unique communication and computation needs that are not met by the existing digital signature techniques. As a result, a lightweight signature scheme is required to meet the communication and computation requirements. In this researc…
Rural Population in Romania. Development and Tendencies (2000 – 2010)
2013
Abstract Demography is among the top factors which exert an undeniable influence upon the economic environment. Therefore, the populace - through its dynamics and characteristics - leaves an imprint upon the social and economic landscape, being a keen barometer and contributing to economic progress. The relationship demography-economy is extremely tight, since the populace is perceived as being a true representation of what characterizes our economy. Romania originated as a country with an agriculture-based economy – a fact which translated in its major rural population; nowadays, due to a sum of various developments, the rural populace is undergoing a decreasing trend. The situation is all…
Influence of uniaxial pressure on dielectric properties of (1- x )Na 0.5 Bi 0.5 TiO 3– x SrTiO 3 for x = 0.01, 0.04, and 0.1 ceramics
2017
The publication costs of this article were covered by the Estonian Academy of Sciences and the University of Tartu.