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Number of results: 6
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Abstract

Humidity is probably the most important abiotic factor influencing life cycles, distribution, survival, and population dynamics of stored product pests. Although most of these pests can complete their life cycles in any given relative humidity, their prolonged development time, as well as decreased emergence rate and fecundity, have been well documented in several previous studies. In the present study, we evaluated the changes in energetic substances (lipids, soluble carbohydrates, glycogen, and proteins) accumulated in different life stages of larvae and adults of Tribolium castaneum in response to different relative humidity levels (5, 12, 22, 30, 45, and 65%). The results showed that young larvae were more susceptible to low relative humidity levels and desiccation stress. Larvae tended to accumulate higher proportions of lipids during earlier stages while their energy content shifted towards proteins with an increase in their age. Adult beetles experienced a significant decrease in their protein content immediately after they initiated reproduction. The importance of these fluctuations in the biology of the red flour beetles was discussed in detail.

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Authors and Affiliations

Mahdiyeh Bigham
Seyed Mohammad Ahsaei
Vahid Hosseininaveh
Hossein Allahyari
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Abstract

The paper presents studies of mathematical modelling in transonic flow through the first stage rotor of the axial compressor of homogenous and heterogeneous condensation. The condensation phenomena implemented into a commercial software is based on the classical theory of nucleation and molecular-kinetic droplet growth model. Model is validated against experimental studies available in the literature regarding the flow through the first stage of turbine compressor, i.e. the rotor37 transonic compressor benchmark test. The impact of air humidity and air contamination on the condensation process for different flow conditions is examined. The influence of latent heat release due to condensation exerts a significant impact on the flow structure, thus the analysis of the air humidity and contamination influence on the condensation is presented. The results presented indicate the non-negligible influence of air humidity on the flow structure in the transonic flow regime, thus it is recommended to take condensation phenomenon under consideration in high-velocity airflow simulations.

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Authors and Affiliations

Piotr Paweł Wiśniewski
Sławomir Dykas
Guojie Zhang
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Abstract

LTCC-based pressure sensors are promising candidates for wet-wet applications in which the effect of the surrounding media on the sensor's characteristics is of key importance. The effect of humidity on the sensor's stability can be a problem, particularly in the case of capacitive sensors. A differential mode of operation can be a good solution, but manufacturing the appropriate sensing capacitors remains a major challenge. In the case of piezoresistive sensors the influence of humidity is less critical, but it still should be considered as an important parameter when designing sensors for low-pressure ranges. In this paper we discuss the stability of the sensors' offset characteristics, which was inspected closely using experimental and numerical analyses.

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Authors and Affiliations

Darko Belavič
Marina Zarnik
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Abstract

The risk of human exposure to finely-dispersed aerosol particles being airborne indoors is determined by the size and the number concentration of particles, the intensity of an aerosol emission source, the air filtration and ventilation efficiency, etc. The emphasis in this article is on behaviour patterns of aerosol particles when exposed to ultrasonic and electrostatic fields in different conditions of air temperature and relative humidity. Wood flour having sizes of interest (characteristic particle diameter about 10 μm) is chosen as a model aerosol. The article considers a physical and mathematical model presenting the evolution of aerosol particles in external fields, taking into account the moisture content and the temperature of a dispersive medium. The efficiency of ultrasonic and electrostatic precipitation in different relative humidity and temperature conditions in an enclosed space was studied using optical measurement methods of particle size and concentration.

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Authors and Affiliations

Maria Stepkina
Olga Kudryashova
Alexandra Antonnikova
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Abstract

This paper deals with the acceptability (AKC) and perceived concentration of pollutants (D) emitted by occupants in relation to the specific enthalpy (h) and relative humidity (qi) of indoor air. Measurements of AKC/D/, described by semilogarithmic function depend significantly on both In h and In (jl. The equation fits to the data published in the literature in a reasonably good way. Therefore, it indicates that the linear function between AKC and h which is commonly used in literature yields rough approximations. The proposed equation allows for the validation of the indoor mieroclimatc and brings an idea how to make measurements of the perceived air quality instrumentally and how to control the air conditioning process.
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Authors and Affiliations

Rudolf Burek
Bernard Połednik
Andrzej Raczkowski
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Abstract

This article accounts for the development of a powerful artificial neural network (ANN) model, designed for the prediction of relative humidity levels, using other meteorological parameters such as the maximum temperature, minimum temperature, precipitation, wind speed, and intensity of solar radiation in the Rabat-Kenitra region (a coastal area where relative humidity is a real concern). The model was applied to a database containing a daily history of five meteorological parameters collected by nine stations covering this region from 1979 to mid-2014.
It has been demonstrated that the best performing three-layer (input, hidden, and output) ANN mathematical model for the prediction of relative humidity in this region is the multi-layer perceptron (MLP) model. This neural model using the Levenberg–Marquard algorithm, with an architecture of [5-11-1] and the transfer functions Tansig in the hidden layer and Purelin in the output layer, was able to estimate relative humidity values that were very close to those observed. This was affirmed by a low mean squared error ( MSE) and a high correlation coefficient ( R), compared to the statistical indicators relating to the other models developed as part of this study.
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Authors and Affiliations

Kaoutar El Azhari
1
ORCID: ORCID
Badreddine Abdallaoui
2
Ali Dehbi
1
ORCID: ORCID
Abdelaziz Abdalloui
1
ORCID: ORCID
Hamid Zineddine
1

  1. Moulay Ismail University, Faculty of Sciences, Zitoune, 50000, Meknes, Morocco
  2. University of Oxford, Mathematical Institute, Oxford, United Kingdom

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