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Open AccessArticle
Hypothesis Tests-Based Analysis for Anomaly Detection in Photovoltaic Systems in the Absence of Environmental Parameters
Energies 2018, 11(3), 485; doi:10.3390/en11030485 (registering DOI) -
Abstract
This paper deals with the monitoring of the performance of a photovoltaic plant, without using the environmental parameters such as the solar radiation and the temperature. The main idea is to statistically compare the energy performances of the arrays constituting the PV plant.
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This paper deals with the monitoring of the performance of a photovoltaic plant, without using the environmental parameters such as the solar radiation and the temperature. The main idea is to statistically compare the energy performances of the arrays constituting the PV plant. In fact, the environmental conditions affect equally all the arrays of a small-medium-size PV plant, because the extension of the plant is limited, so any comparison between the energy distributions of identical arrays is independent of the solar radiation and the cell temperature, making the proposed methodology very effective for PV plants not equipped with a weather station, as it often happens for the PV plants located in urban contexts and having a nominal peak power in the 3÷50 kWp range, typically installed on the roof of a residential or industrial building. In this case, the costs of an advanced monitoring system based on the environmental data are not justified, consequently, the weather station is often also omitted. The proposed procedure guides the user through several inferential statistical tools that allow verifying whether the arrays have produced the same amount of energy or, alternatively, which is the worst array. The procedure is effective in detecting and locating abnormal operating conditions, before they become failures. Full article
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Open AccessArticle
“In The End, God Helped Me Defeat Myself”: Autobiographical Writings by Camilla Battista da Varano1
Religions 2018, 9(3), 65; doi:10.3390/rel9030065 (registering DOI) -
Abstract
Camilla Battista da Varano (1458–1524), a mystic and Franciscan nun, spent most of her life in Camerino in east-central Italy. Now a saint—since 17 October 2010—she composed two autobiographical treatises across a ten-year period mid-way through a literary career that spanned the end
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Camilla Battista da Varano (1458–1524), a mystic and Franciscan nun, spent most of her life in Camerino in east-central Italy. Now a saint—since 17 October 2010—she composed two autobiographical treatises across a ten-year period mid-way through a literary career that spanned the end of the fifteenth and the early part of the sixteenth centuries. In one, La vita spirituale (My spiritual life, 1491), she delivered a complete spiritual life story, tracing her religious devotion from the ages of eight to thirty-three. She described her relationship with a number of men, including her father and several clerics who—to one degree or another—inspired and guided her devotional life. By the time she wrote, she had been a professed Franciscan nun for seven years. She presented herself at that point as one who had undergone visionary, mystical experiences and as a woman who had both benefitted and suffered under the control of men like her father and her spiritual directors. In the other, Istruzioni al discepolo (Instructions to a disciple, 1501), she told the story of her affectionate relationship with a male disciple she was directing spiritually but used a literary conceit to hide her own identity. She wrote about the spiritual director the male disciple loved and admired in the third person, apparently in a self-deprecating manner inspired by humility but thinly veiling her obvious self-confidence. In these texts, and in other of her devotional treatises, she claimed the ability to provide spiritual direction of her own and wrote in bold imagery, creatively manipulating scripture at times. She exercised a do-it-yourself approach to discernment of God’s will and even to the process of confession. She criticized inattentive spiritual directors and asserted that both her visions and the impetus for her devotional writings came directly, unmediated, from God. But Camilla also exhibited deferential attitudes and strong connections to traditional Franciscan theology while including female authors in that tradition she apparently admired, like Caterina da Bologna (1413–1463). She also wrote at times with vivid expressions of obedience to the variety of men who held some authority over her. She was, apparently, not an individual easily understood through the standard images usually associated with late medieval and early modern women. A fuller portrait of Camilla is emerging as scholars today seek to recover her original voice. Full article
Open AccessArticle
Assessing Port Governance, Devolution and Terminal Performance in Nigeria
Logistics 2018, 2(1), 6; doi:10.3390/logistics2010006 (registering DOI) -
Abstract
Concerns about performance and efficiency in port terminals led many national governments to embark on port reforms. The Federal government of Nigeria, for example, adopted the Landlord port model which brought about concessioning of port terminals to private operators. Despite high investments in
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Concerns about performance and efficiency in port terminals led many national governments to embark on port reforms. The Federal government of Nigeria, for example, adopted the Landlord port model which brought about concessioning of port terminals to private operators. Despite high investments in terminal facilities by the private terminal operators, there are still complaints about level of service offered to port users. This paper applied key performance indicator metrics and parameters of queuing model in assessing performance of Nigeria’s concessioned port terminals. Data for the study were obtained from terminal level records of cargo and ship handling activities for years 2000 to 2015. Major findings indicate that cargo and vessel throughputs improved after the reforms in the six ports examined. However, much variability was observed in trends in ships’ turnround times across all ports after the concession policy implementation. Additional results from the queuing model analysis suggest that the high ships turnround times observed in some ports are associated to delays in ship operation at the berths. The paper recommends that policy interventions be focused on ship operations at the berths as a step in improving service level in the port terminals. Full article
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Open AccessReview
Meningococcal Vaccines: Current Status and Emerging Strategies
Vaccines 2018, 6(1), 12; doi:10.3390/vaccines6010012 (registering DOI) -
Abstract
Neisseria meningitidis causes most cases of bacterial meningitis. Meningococcal meningitis is a public health burden to both developed and developing countries throughout the world. There are a number of vaccines (polysaccharide-based, glycoconjugate, protein-based and combined conjugate vaccines) that are approved to target five
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Neisseria meningitidis causes most cases of bacterial meningitis. Meningococcal meningitis is a public health burden to both developed and developing countries throughout the world. There are a number of vaccines (polysaccharide-based, glycoconjugate, protein-based and combined conjugate vaccines) that are approved to target five of the six disease-causing serogroups of the pathogen. Immunization strategies have been effective at helping to decrease the global incidence of meningococcal meningitis. Researchers continue to enhance these efforts through discovery of new antigen targets that may lead to a broadly protective vaccine and development of new methods of homogenous vaccine production. This review describes current meningococcal vaccines and discusses some recent research discoveries that may transform vaccine development against N. meningitidis in the future. Full article
Open AccessConference Report
A Way Out of the Bubble Trouble?—Upon Reconstructing the Origin of the Local Bubble and Loop I via Radioisotopic Signatures on Earth
Galaxies 2018, 6(1), 26; doi:10.3390/galaxies6010026 (registering DOI) -
Abstract
Deep-sea archives all over the world show an enhanced concentration of the radionuclide {\fe}, isolated in layers dating from about $\unit[2.2]{Myr}$ ago. Since this comparatively long-lived isotope is not naturally produced on Earth, such an enhancement can only be attributed to extraterrestrial sources,
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Deep-sea archives all over the world show an enhanced concentration of the radionuclide {\fe}, isolated in layers dating from about $\unit[2.2]{Myr}$ ago. Since this comparatively long-lived isotope is not naturally produced on Earth, such an enhancement can only be attributed to extraterrestrial sources, particularly one or several nearby supernovae in the recent past. It has been speculated that these supernovae might have been involved in the formation of the Local Superbubble, \mbox{\textls[-15]{our~Galactic habitat. Here, we summarize our efforts in giving a quantitative evidence for this scenario.}} Besides~analytical calculations, we present results from high-resolution hydrodynamical simulations of the Local Superbubble and its presumptive neighbor Loop~I in different environments, including a self-consistently evolved supernova-driven interstellar medium. For the superbubble modeling, the time sequence and locations of the generating core-collapse supernova explosions are taken into~account, which are derived from the mass spectrum of the perished members of certain, carefully~preselected stellar moving groups. The release and turbulent mixing of {\fe} is followed via passive scalars, where the yields of the decaying radioisotope were adjusted according to recent stellar evolution calculations. The models are able to reproduce both the timing and the intensity of the {\fe} excess observed with rather high precision. We close with a discussion of recent developments and give future perspectives. Full article
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Open AccessReview
Recent Advances in Solvents for the Dissolution, Shaping and Derivatization of Cellulose: Quaternary Ammonium Electrolytes and their Solutions in Water and Molecular Solvents
Molecules 2018, 23(3), 511; doi:10.3390/molecules23030511 (registering DOI) -
Abstract
There is a sustained interest in developing solvents for physically dissolving cellulose, i.e., without covalent bond formation. The use of ionic liquids, ILs, has generated much interest because of their structural versatility that results in efficiency as cellulose solvents. Despite some limitations, imidazole-based
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There is a sustained interest in developing solvents for physically dissolving cellulose, i.e., without covalent bond formation. The use of ionic liquids, ILs, has generated much interest because of their structural versatility that results in efficiency as cellulose solvents. Despite some limitations, imidazole-based ILs have received most of the scientific community’s attention. The objective of the present review is to show the advantages of using quaternary ammonium electrolytes, QAEs, including salts of super bases, as solvents for cellulose dissolution, shaping, and derivatization, and as a result, increase the interest in further investigation of these important solvents. QAEs share with ILs structural versatility; many are liquids at room temperature or are soluble in water and molecular solvents (MSs), in particular dimethyl sulfoxide. In this review we first give a historical background on the use of QAEs in cellulose chemistry, and then discuss the common, relatively simple strategies for their synthesis. We discuss the mechanism of cellulose dissolution by QAEs, neat or as solutions in MSs and water, with emphasis on the relevance to cellulose dissolution efficiency of the charge and structure of the cation and. We then discuss the use of cellulose solutions in these solvents for its derivatization under homogeneous and heterogeneous conditions. The products of interest are cellulose esters and ethers; our emphasis is on the role of solvent and possible side reactions. The final part is concerned with the use of cellulose dopes in these solvents for its shaping as fibers, a field with potential commercial application. Full article
Open AccessArticle
Robust Condition Assessment of Electrical Equipment with One Class Support Vector Machines Based on the Measurement of Partial Discharges
Energies 2018, 11(3), 486; doi:10.3390/en11030486 (registering DOI) -
Abstract
This paper presents a system for the detection of partial discharges (PD) in industrial applications based on One Class Support Vector Machines (OCSVM). The study stresses the detection of Partial Discharges (PD) as they represent a major source of information related to degradation
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This paper presents a system for the detection of partial discharges (PD) in industrial applications based on One Class Support Vector Machines (OCSVM). The study stresses the detection of Partial Discharges (PD) as they represent a major source of information related to degradation in the equipment. PD measurement is a widely extended technique for condition monitoring of electrical machines and power cables to avoid catastrophic failures and the consequent blackouts. One of the most important keystones in the interpretation of partial discharges is their separation from other signals considered as not-PD especially in low SNR measurements. In this sense, the OCSVM is an interesting alternative to binary SVMs since it does not need a training set with examples of all the output classes correctly labelled. On the contrary, the OCSVM learns a model of the signals acquired when the equipment is in PD-free mode, defined as a state where no degradation mechanism is active, so one only needs to make sure that the training signals were recorded under this setting. These default mode signals are easier to characterize and acquire in industrial environments than PD and lead to more robust detectors that practically do not need domain adaptation to perform in scenarios prone to different types of PD. In fact, the experimental results show that the performance of the OCSVM is comparable to that achieved by a binary SVM trained using both noise and PD pulses. Finally, the method is successfully applied to a more realistic scenario involving the detection of PD in a damaged distribution power cable. Full article

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