Presence Of Adverse Environmental Conditions Research Articles

A Statistical Methodology to Estimate Soiling Losses on Photovoltaic Solar Plants

Abstract One of the challenges in photovoltaic solar plants is the performance maintenance in the presence of adverse environmental conditions. Soiling on the solar panels is one of those challenges having a high decrease impact on the power generation. This work proposes a statistical methodology that estimates the energy losses due to soiling on photovoltaic solar plants. Using environmental and power generation data, the proposed methodology predicts the energy generation using a regression model; and then evaluates if the differences between the observed energy generation data and the predicted energy data are due to soiling. The experiments to validate the system are based on one-year dataset of environmental and power generation data from a solar plant located in the northeast region of Brazil. The results showed that the daily energy losses estimates ranged from 2.20% up to 12.31% in a period less than a month.

Dissolved air flotation combined to biosurfactants: a clean and efficient alternative to treat industrial oily water

The present review was motivated by the increasing demand of environmental regulatory agencies for the treatment of oily water generated during industrial activities. Flotation is a promising process for this purpose. Particularly, dissolved air flotation (DAF) is the most indicated technology due to its high efficiency and the possibility of controlling the physical variables, such as microbubble size, residence time and concentration of the effluent. DAF can also be optimised with the use of biodegradable tensioactive agents that increase the adhesion of oil particles, thereby enhancing the efficiency of the process. Among such tensioactive agents, biosurfactants are a viable, innovative, eco-friendly option with important properties, such as a reduction in surface tension, low toxicity and stability in the presence of adverse environmental conditions. Therefore, the aim of the present review is to offer a new perspective regarding the use of the flotation process combined with these specific biomolecules.

On the Effects of Communication Range Shrinkage of Sensor Nodes in Mobile Wireless Sensor Networks Due to Adverse Environmental Conditions

A wireless sensor network (WSN) is a collection of spatially distributed sensor nodes working collaboratively to monitor a physical environment. A mobile wireless sensor network (MWSN) is a specific type of WSN, in which the sensor nodes move within a designated area. In this paper, we consider the effects of adverse environmental conditions on MWSN. Conditions such as high temperature, rainfall, and fog cause attenuation and fading effects on the communication of sensor nodes. Consequently, the communication ranges of such nodes shrink, and the sensor nodes cannot communicate with any of their peers. The shrinkage in communication range creates impairment in the normal communication ability of sensor nodes, which results in link disruption, packet loss, performance degradation, and reduced lifetime of the network. As the adverse environmental conditions are temporal in nature, the sensor nodes function normally with the resumption of favorable environmental conditions. The existing literature did not consider this type of temporary problem on MWSNs. In this paper, we evaluated the performance of MWSN due to the presence of adverse environmental conditions. Simulation results confirm the hypotheses that the performance of MWSN degrades in the presence of adverse environmental conditions. From the results it can be inferred that throughput and delivery ratio nearly decreases by 66% and 42%, respectively, whereas delay increases by 75% due to the shrinkage in communication range.

A transcriptomic investigation of handicap models in sexual selection

Handicap models link the evolution of secondary sexual ornaments to physiological costs and thus provide a mechanistic explanation for signal honesty in sexual selection. Two commonly invoked models, the immunocompetence handicap hypothesis (ICHH) and the oxidative stress handicap hypothesis (OSHH), propose suppression of immunocompetence or increase of oxidative stress by testosterone, but empirical evidence for both models is controversial and based on morphological and physiological assays. Here, we investigated these two models on the gene transcription level using microarrays to quantify the transcriptomic response of red grouse (Lagopus lagopus scoticus) caecal, spleen and liver tissues to experimental manipulation of testosterone levels. We used a geneontology framework to identify genes related to immune function and response to reactive oxygen species and examined how transcription levels changed under experimentally increased testosterone levels in birds with parasites present or absent. Contrary to our expectations, testosterone had virtually no effect on gene transcription in spleen and liver. A small number of genes were significantly differentially regulated in caecum, and while their functions and transcription changes are consistent with the ICHH, we found little support for the OSHH. More genes responded to testosterone in the presence rather than absence of parasites, suggesting that handicap mechanisms may be context dependent and more pronounced in the presence of adverse environmental conditions. These findings illustrate the utility of transcriptomics to investigating handicap models, suggest that classic models may not underlie the handicap mechanism, and indicate that novel emerging models involving different mediators and physiological systems should be examined.

Developmental origins of adult metabolic disease: The Indian scenario, driving toward a unified hypothesis

. proposed that an individual’s adaptation to the environment is dependent on genes selected over a long period of time (“thrifty-genotype”), i.e., those genes that once favored survival in the presence of adverse environmental conditions, evolved into a status of being detrimental in circumstances of sustained energy surplus.

Anomaly detection in hyperspectral imagery: comparison of methods using diurnal and seasonal data

The use of hyperspectral imaging is a fast growing field with many applications in the civilian, commercial and military sectors. Hyperspectral images are typically composed of many spectral bands in the visible and infrared regions of the electromagnetic spectrum and have the potential to deliver a great deal of information about a remotely sensed scene. One area of interest regarding hyperspectral images is anomaly detection, or the ability to find spectral outliers within a complex background in a scene with no a priori information about the scene or its specific contents. Anomaly detectors typically operate by creating a statistical background model of a hyperspectral image and measuring anomalies as image pixels that do not conform properly to that given model. In this study we compare the performance over diurnal and seasonal changes for several different anomaly detection methods found in the literature and a new anomaly detector that we refer to as the fuzzy cluster-based anomaly detector. Here we also compare the performance of several anomaly-based change detection algorithms. Our results indicate that all anomaly detectors tested in this experimentation exhibit strong performance under optimum illumination and environmental conditions. However, our results point toward a significant performance advantage for cluster-based anomaly detectors in the presence of adverse environmental conditions.

Proteins from extremophiles as stable tools for advanced biotechnological applications of high social interest.

Extremophiles are micro-organisms adapted to survive in ecological niches defined as 'extreme' for humans and characterized by the presence of adverse environmental conditions, such as high or low temperatures, extreme values of pH, high salt concentrations or high pressure. Biomolecules isolated from extremophiles possess extraordinary properties and, in particular, proteins isolated from extremophiles represent unique biomolecules that function under severe conditions, comparable to those prevailing in various industrial processes. In this article, we will review some examples of recent applications of thermophilic proteins for the development of a new class of fluorescence non-consuming substrate biosensors for monitoring the levels of two analytes of high social interest, such as glucose and sodium.