12 research outputs found
A review of anti-reflection and self-cleaning coatings on photovoltaic panels
No full textThe production of electrical energy from solar energy through the photovoltaic method has become increasingly widespread throughout the world in the last 20 years. The photovoltaic energy system generates electricity depending on the amount of sunlight reaching the solar cell, and the amount of sunlight that reaches the solar cells in a solar panel decreases due to factors such as soil and organic dirt. At the same time, sunlight is refracted and reflected due to the reflective effect of the cover glass surface, even if the surface of the photovoltaic panel is clean. The remaining solar rays are broken and reach the solar cell. Decreasing sunlight also causes a decrease in electrical power output. Thus, to overcome these problems, photovoltaic solar cells and cover glass are coated with anti-reflective and self-cleaning coatings. As observed in this study, SiO2, MgF2, TiO2, Si3N4, and ZrO2 materials are widely used in anti-reflection coatings. Common methods used are sol-gel + spin-coating or + dipcoating, sputtering, DC or RF magnetron, and electrospun methods. Regarding self-cleaning applications, fabricating superhydrophobic surfaces stands out among other methods. In self-cleaning applications, Al2O3, TiO2, and Si3N4 are the most suitable materials; the double- and triple-layer coatings yield successful results in terms of surface adhesion and durability. In multi-layer anti-reflection coatings, the reflectance was reduced in studies in which materials with low and high reflection indexes were applied and light transmittance was increased
A Hydrophobic Antireflective and Antidust Coating With and Nanoparticles Using a New 3-D Printing Method for Photovoltaic Panels
No full textThe main outdoor factors that reduce the efficiency of the photovoltaic (PV) panel are the reflection and refraction of light, dirt, dust, and organic waste accumulating on the panel surface. In this article, an antireflection, self-cleaning coating was applied on the PV panel cover glass with a new method. With the coating, the surface has been given a hydrophobic feature. As a coating method, a 3-D printer has not been seen in the literature and used as a new method. The electrospinning method has also been tried as an alternative method. Solutions in different combinations were developed using polylactic acid or polymethylmethacrylate polymer, chloroform () as a solvent, and silicon dioxide () and titanium dioxide () nanoparticles as primary materials in a modified 3-D printer for bioprinting. Five PV panels were obtained by applying different 3-D parameters from three solutions, which have the best results. Coating thicknesses are in the range of 3.12-8.47 mu m. Coated and uncoated PV panels were tested in outdoor conditions for ten-day periods. The power outputs of the PV panels were measured, and their ten-day average efficiency was presented. According to the results, the highest efficiency increase is 8.7%. The highest light transmittance is 88.2% at 550 nm. In addition, hydrophobic properties were observed on all surfaces and the water contact angle was measured as 96.18 degrees
Semi-conductor Applications to Printed Circuits on Flexible Surfaces
No full textThe most common type of identification system today is RFID. RFID circuits are used as covered with plastic. With the increase in usage areas, it is also used on metal, wood, paper, and plastic product. In this study, the behavior of the same circuit on different surfaces was investigated. The surface impedance and signal reflection coefficients of RFID tag antennas were investigated based on paper, plastic, and textile surfaces. According to the results of the electrical and mechanical tests, the best results in terms of reflectance coefficients and surface impedances of RFID tags are on PET surfaces. The surface impedance and the reflection coefficients were high on paper surfaces. The lowest values were measured on textile surfaces. According to the results, it has been seen that RFID antenna application on plastic, paper, and textile surfaces is possible and usable.</jats:p
Author Reputation Measurement on Question and Answer Sites by the Classification of Author-Generated Content
No full textIn the field of software engineering, practitioners' share in the constructed knowledge cannot be underestimated and is mostly in the form of grey literature (GL). GL is a valuable resource though it is subjective and lacks an objective quality assurance methodology. In this paper, a quality assessment scheme is proposed for question and answer (Q;A) sites. In particular, we target stack overflow (SO) and stack exchange (SE) sites. We model the problem of author reputation measurement as a classification task on the author-provided answers. The authors' mean, median, and total answer scores are used as inputs for class labeling. State-of-the-art language models (BERT and DistilBERT) with a softmax layer on top are utilized as classifiers and compared to SVM and random baselines. Our best model achieves 63.8% accuracy in binary classification in SO design patterns tag and 71.6% accuracy in SE software engineering category. Superior performance in SE software engineering can be explained by its larger dataset size. In addition to quantitative evaluation, we provide qualitative evidence, which supports that the system's predicted reputation labels match the quality of provided answers
A review of anti-reflection and self-cleaning coatings on photovoltaic panels
No full textThe production of electrical energy from solar energy through the photovoltaic method has become increasingly widespread throughout the world in the last 20 years. The photovoltaic energy system generates electricity depending on the amount of sunlight reaching the solar cell, and the amount of sunlight that reaches the solar cells in a solar panel decreases due to factors such as soil and organic dirt. At the same time, sunlight is refracted and reflected due to the reflective effect of the cover glass surface, even if the surface of the photovoltaic panel is clean. The remaining solar rays are broken and reach the solar cell. Decreasing sunlight also causes a decrease in electrical power output. Thus, to overcome these problems, photovoltaic solar cells and cover glass are coated with anti-reflective and self-cleaning coatings. As observed in this study, SiO2, MgF2, TiO2, Si3N4, and ZrO2 materials are widely used in anti-reflection coatings. Common methods used are sol-gel + spin-coating or + dipcoating, sputtering, DC or RF magnetron, and electrospun methods. Regarding self-cleaning applications, fabricating superhydrophobic surfaces stands out among other methods. In self-cleaning applications, Al2O3, TiO2, and Si3N4 are the most suitable materials; the double- and triple-layer coatings yield successful results in terms of surface adhesion and durability. In multi-layer anti-reflection coatings, the reflectance was reduced in studies in which materials with low and high reflection indexes were applied and light transmittance was increased.Marmara University, Turkey, Scientific Research Committee [FEN-E-120514-0149]This project supported by the Marmara University, Turkey, Scientific Research Committee. Project No: FEN-E-120514-0149
Grid connected photovoltaic system design an example application for İstanbul province
No full textIt is seen that the damage to the environment has increased with the use of fossil fuels around the world. It is known that studies continue to minimize the damage to the environment with alternative energy generation methods. Recently, it is seen that generating electrical energy using solar energy, known as clean energy, has an important place. With the developing semiconductor technologies, the use of photovoltaic systems is increasing day by day. The aim of this study is to estimate the amount of energy that will be produced by simulating and modeling the performance of PV (Photovoltaic) systems using PVsyst and PV*SOL programs before the Photovoltaic systems are installed in the region. In the study, grid-connected roof system modeling was made in Bakırköy district of Istanbul province. In the modeling of the system, a total of 90 solar panels were placed on an area of 114.9 m2 , in East and West directions. In total, it is predicted that 17.1 kW of energy will be obtained when the system is used. In the system design, the avoided CO₂ emission is calculated as 8,856 kg/year and the amortization period is calculated as 7.2 years. When the programs are used, the analysis of the system is made before the implementation and it is seen that time and cost savings are achieved
Survey on LED Light Source Solar Simulators
No full textBu çalışmada; fotovoltaik cihazların testlerini gerçekleştiren ve son yıllarda kullanımı giderek artan LED ışık kaynaklı solar simülatörler incelenmiştir. Bu amaçla giriş kısmında yenilenebilir enerji kaynaklarından güneş enerjisinin önemi vurgulanmış, solar simülatörlerin tanımı ve gerekliliği açıklanmıştır. Sonraki bölümlerde ise güneş ışığı detayları belirtilmiş, solar simülatörlerde kullanılan diğer ışık kaynakları incelenmiş, LED ışık kaynaklarının diğerlerine göre farkları ortaya konulmuştur. LED solar simülatörler için ASTM E927-10 ve IEC- 60904-9 standartlarında belirtilen performans kriterleri detaylandırılmış ve bu kriterlerin belirlenmesindeki değerler formüle edilmiştir. Yine aynı standartlar doğrultusunda LED solar simülatörler konusunda gerçekleştirilen bilimsel çalışmalar incelenmiş ve kronolojik olarak detaylandırılmıştır. Çalışmanın sonunda solar simülatörlerde kullanılan ışık kaynaklarının avantaj ve dezavantajları bir tablo halinde sunulmuştur. Karşılaştırma sonrasında solar simülatörlerde ışık kaynağı olarak kullanılan LED’lerin önemi ve gerekliliği vurgulanmıştır
An interpretable statistical approach to photovoltaic power forecasting using factor analysis and ridge regression
No full textAbstract Accurate forecasting of solar energy is essential for balancing supply and demand, enhancing energy planning, and supporting the integration of renewable resources into modern electricity grids. While recent research has heavily focused on machine learning-based models such as Long Short-Term Memory networks for solar energy forecasting, these approaches often lack transparency and interpretability. This study presents an interpretable by design photovoltaic (PV) forecasting framework that couples hierarchical factor analysis (HFA) with ridge regression. HFA compresses high dimensional meteorology into three physics meaningful second order factors after which a single parameter ridge model provides coefficient level transparency and regularization in this compact space. Using 15 min measurements from a 93.6 kWp plant in Adıyaman, Türkiye (May 17, 2021–Jan 12, 2025), we evaluate under a unified chronological split (0.64/0.16/0.20). The model combines strong generalization with clear insights into how meteorological variables affect solar power generation, ensuring transparency and verifiability. These results highlight regression-based methods as robust, explainable alternatives to complex deep learning models in photovoltaic forecasting.Since development and forecasting using highly multivariate models is typically not an easy task, our approach is designed to provide a more streamlined model through which future prediction is easier. Simplifying complexity and making it easier to understand how parameters affect the result, our proposed model simplifies finding the most important drivers of solar power generation
Prediction of white layer formation in ?-WEDM process of NiTi shape memory superalloy: FEM with experimental verification
No full textMicroscopic changes in the surface of nickel-titanium (nitinol) shape memory alloys (SMAs) in micro-wire electro-discharge machining (?-WEDM) due to the formation of a resolidified layer on the machined surface, called white layer, are one of the main drawbacks in the processing of such alloys. Since these changes significantly affect the shape memory and elastic recovery characteristics of these alloys, reduction of the white layer thickness (WLT) based on the selection of optimum process parameters is essential to raise the quality of the machined parts. In this regard, a finite element model (FEM) has been developed to simulate the effects of ?-WEDM process parameters, including discharge current, pulse on-time, pulse off-time, and servo voltage, on the heat distributing in Ni55.8Ti SMA to predict the WLT. The flushing efficiency of electric discharges and the effect of flow regime of the dielectric fluid on the heat distribution in the workpiece and the formation of the WLT are analyzed. Experimental data are used to verify the accuracy of the FEM. The results show that the developed model can predict the WLT in ?-WEDM process of Ni55.8Ti SMA with an average error of 14%. The effects of discharge parameters on the formation of the WLT are discussed in details based on the results of the FEM. © 2021, The Author(s), under exclusive licence to Springer-Verlag London Ltd. part of Springer Nature.Bilkent Üniversites
Exploring the context and potential benefits of implementing an Intermittent Preventive Treatment for malaria in infants (IPTi) in Papua New Guinea
No full textSummary: Background
Intermittent preventive treatment (IPTi) is an intervention aiming to reduce the
risk of malaria in infants. Its concept is to deliver a full treatment course of
antimalarial drugs to infants, three or four times during the first year of life,
following the expanded program of immunization (EPI) schedule and regardless
of clinical malaria episodes.
Mainly Sulphadoxine/pyrimthamine (SP) was studied and demonstrated to
reduce the risk of malaria by 30% in Africa, where Plasmodium falciparum (Pf) is
the predominant species. No study has been carried out in regions of the world
with a significant burden of non-Pf infections. There is therefore a need to
investigate the potential benefits of IPTi in areas, such as Papua New Guinea
(PNG), highly endemic for Plasmodium vivax (Pv) malaria.
Apart from efficacy, which is the corner stone of an intervention, it is essential to
have a clear picture of the context in which such an intervention might be
implemented. Indeed, determinants of effectiveness such as the malaria context
(epidemiology and case management), the acceptability and the access to the
intervention need to be investigated prior to the implementation of IPTi.
The present study investigates the efficacy of IPTi in PNG as well as some key
aspects of infant’s health in PNG that might help to understand the context in
which IPTi could be implemented.
Methods
Randomized controlled trial investigating the protective efficacy of 4 doses of SP
associated to 3 days of artesunate (SP-AS3) or 3 days of amodiaquine (SP-AQ3)
given at 3-month intervals during the first year of life. Most of infants were
followed-up for an additional 12 months. The study took place in Madang and
Maprik (PNG) from 2006 to 2010, but only the Madang cohort was used for the
IPTi efficacy analyses.
Making use of the morbidity passive case detection of the trial, the following
aspects of infant’s health in PNG were investigated:
· Effectiveness of treating infants with a unified treatment
(artemther/lumefantrine, AL) for Pf & Pv malaria based on the result of the
rapid diagnostic test (RDT)
· The incidence of common illnesses based on RDT and syndromic
definitions of diseases and the impact of IPTi on them.
· The performances of the integrated management childhood illness (IMCI)
supplemented with RDT & IPTi for the management of common
syndromes/diseases in PNG.
The acceptability of IPTi was also assed alongside the drug trial.
Findings
1605 infants 3 months old were enrolled in the IPTi trial, 1125 in Madang and 480
in Maprik. The intention-to-treat relative risk (RR) at 15 months of age (Madang
site only) was 0.72 (95%CI, 0.57 - 0.90) on all malaria episodes with SP-AQ3 and
0.88 (95%CI, 0.70 - 1.10) with SP-AS3, overall p=0.017. Using SP-AQ3, the RR
was 0.63 (95%CI, 0.45 - 0.88) on Pf and 0.78 (95%CI, 0.60 - 1.01) on Pv. No
difference was observed in the incidence of overall morbidity, severe diseases
and non-malarial illnesses between the placebo and IPTI intervention arms.
Fewer deaths were observed in the treatment arms compared to placebo:
placebo=8, SP-AQ3=1 and SP-AS3=3.
7223 fever episodes occurred (in Madang and Maprik) during the study and 5670
had a negative RDT result. Out of them, 133 (3.4%) re-attended the clinic within
7 days for fever, and 1 died of lower respiratory tract infection (LRTI). 23 (0.6%)
infants re-presented with a severe illness (4 with positive BS and/or RDT). 1728
children with positive RDT results were treated with artemether/lumefantrine (AL).
30 (1.7%) re-attended within 7 days for fever, none died.
Out of the total cohort, incidence rates (episodes/child/year) for common
syndromes/diseases were: 0.85 (95%CI, 0.81-0.90) for LRTI, 0.72 (95%CI, 0.65-
0.93) for gastroenteritis (GI), 0.62 for malaria (95%CI, 0.58 - 0.66) and 0.08
(95%CI, 0.07-0.09) for otitis.
The introduction of RDT led to a high accuracy of “on site” malaria diagnosis (К
=0.99). On the opposite, the clinical diagnosis accuracy for others syndromes
was poor: К=0.47 for LRTI, К=0.52 for GI and К= 0.52 for otitis.
25% of illness episodes were inappropriately treated: 6% did not receive
antibiotics when they should have and 19% received antibiotics when they should
not have (according to recommendations). The prescription’s rate of antibiotics
was 56% when the RDT for malaria was negative and 16% when the RDT was
positive (p<0.001). The acceptability of IPTi appears to be good in Melanesian
populations.
Conclusion
The use of RDT and artemether/lumefantrine is a safe and effective strategy for
the management of malaria cases in PNG and could be implemented very easily.
IPTi has demonstrated its efficacy to reduce both Pf and Pv episodes. However,
the apparent absence of benefit on the overall morbidity and on severe illnesses
is a concern and mitigates the interest of implementing this intervention in PNG.
Furthermore, other factors such as a low EPI coverage and rapidly changing
malaria endemicity due to the recent introduction in PNG of insecticide treated
nets (ITN) and artemisinin combination therapies (ACT) are likely to jeopardize
the potential benefits of IPTi in PNG. ---------- Zusammenfassung:
Hintergrund
Intermittent preventive treatment in infants (IPTi) ist eine Intervention mit dem
Ziel, das Risiko von Malaria bei Kleinkindern zu reduzieren. Sein Konzept ist den
Säuglingen Behandlung mit Malariamedikamenten, drei oder viermal während
des ersten Lebensjahres, nach dem Zeitplan des Erweitertens Programms der
Immunisierung (EPI) und unabhängig von klinischen Malaria Episoden.
Haupsächlich Sulfadoxin/pyrimthamine (SP) wurde studiert und zeigte, dass das
Risiko von Malaria um 30% in Afrika reduziert wurde, wo Plasmodium falciparum
(Pf) die vorherrschende Spezies ist. Keine Studie wurde in den Regionen der
Welt mit einer signifikanten Belastung durch nicht-Pf-Infektionen durchgeführt. Es
besteht daher ein Bedarf, die potenziellen Vorteile der IPTi in Bereichen wie
Papua-Neuguinea (PNG), hoch endemisch für Plasmodium vivax (Pv) Malaria,
zu untersuchen.
Abgesehen von Wirksamkeit, die der Grundstein für eine Intervention ist, ist es
wichtig, ein klares Bild des Kontextes zu haben, in dem ein solcher Eingriff
durchgeführt werden könnte. Tatsächlich, Determinante der Wirksamkeit wie der
Malariakontext (Epidemiologie und Case Management), die Akzeptanz und der
Zugang auf die Intervention, muss vor der Durchführung von IPTi untersucht
werden.
Die vorliegende Studie untersucht die Wirksamkeit von IPTi in PNG sowie einige
der wichtigsten Aspekte der kindlichen Gesundheit von Kleinkindern in PNG, die
helfen könnten, den Kontext, in dem IPTi implementiert werden könnte, zu
verstehen.
Methoden
Randomisierte kontrollierte Studie, die die schützende Wirkung untersucht von
vier Dosen von SP und 3 Tagen von Artesunat (SP-AS3) oder 3 Tage von
Amodiaquin (SP-AQ3) in 3-monatigen Abständen, gegeben während des ersten
Lebensyahres. Die meisten Kinder wurden für weitere 12 Monate beobachtet.
Die Studie fand in Madang und Maprik (PNG) von 2006 bis 2010 statt, aber nur
die Madang Kohorte wurde für die IPTi Wirksamkeit Analyse verwendet.
Folgende Aspekte der Gesundheit der Kleinkinder in PNG wurden untersucht,
indem die passiven Fälle der Studie registriert wurden:
• Wirksamkeit der Behandlung von Säuglingen mit einer einheitlichen
Behandlung (artemther / Lumefantrin, AL) für Pf & Pv Malaria, dem Ergebnis des
rapid diagnostic test (RDT) nach.
• Die Inzidenz von gewöhnlichen Krankheiten nach RDT und syndromalen
Definitionen von Krankheiten und die Auswirkungen von IPTi auf ihnen.
• Die Leistungen des integrierten Managementsystems Kinderkrankheiten (IMCI)
ergänzt mit RDT & IPTi für die Bewirtschaftung der gewöhnlichen Syndrome / in
PNG.
Die Akzeptanz von IPTi wurde während dieser Studie bestimmt .
Resultate
1605 3-Monate alt Säuglinge wurden in die IPTi Studie eingezogen, 1125 in
Madang und 480 in Maprik. Intention-to-treat relative Risiko (RR) bei 15 Monaten
alt betrug 0.72 (95% CI, 0.57 bis 0.90) auf allen Malariaepisoden mit SP-AQ3
und 0.88 (95% CI, 0.70 bis 1.10) mit SP-AS3, Insgesamt p = 0.017. Mit SP-AQ3
wurde das RR 0.63 (95% CI, 0.45 bis 0.88) auf Pf und 0.78 (95% CI, 0.60 bis
1.01) auf Pv. Es wurde kein Unterschied in der Inzidenz von insgesamter
Morbidität, schwere Erkrankungen und nicht-Malaria-Erkrankungen zwischen der
Placebo-und IPTi Intervention Arme beobachtet. Nur wenige Todesfälle wurden
in den Behandlungsgruppen im Vergleich zu Placebo beobachtet: Placebo = 8,
SP-AQ3 = 1 und SP-AS3 = 3 ist.
7223 Fieberepisode (in Madang und Maprik) sind während der Studie
aufgetreten und 5670 hatten einen negativen RDT. Aus ihnen, 133 (3.4%)
besuchten die Klinik innerhalb von 7 Tagen bei Fieber wieder und 1 starb an
unteren Atemwegeinfektion (LRTI). 23 (0.6%) Säuglinge kamen erneut mit einer
schweren Krankheit (4 mit positiven BS und / oder RDT). 1728 Kinder mit
positiven RDT Ergebnissen wurden mit Artemether / Lumefantrin (AL) behandelt.
30 (1.7%) besuchten die klinik innerhalb von 7 Tagen bei Fieber wieder, keiner
starb.
Von der insgesamten Kohorte waren Inzidenzraten (Episode / Kind / Jahr) für
gemeinsame Syndrome / Krankenheiten : 0.85 (95% CI, 0.81-0.90) für LRTI, 0.72
(95% CI, 0.65-0.93) für Gastroenteritis (GI), 0.62 f!ur malaria (95%CI, 0.58 - 0.66)
und 0.08 (95% CI, 0.07-0.09) für Otitis.
Die Einführung von RDT führte zu einer hohen Genauigkeit von "on site"
Malaria-Diagnose (К = 0.99). Im gegenteil, war die Genauigkeit klinischer
Diagnose für andere Syndrome schlecht : К = 0.47 für LRTI, К = 0.52 für GI und
К = 0.52 für Otitis.
25% der Krankheitsepisoden wurden unsachgemäß behandelt: 6% erhielten
keine Antibiotica, wenn sie sie haben sollten und 19% erhielten Antibiotika, wenn
sie sie nicht haben sollten (den Empfehlungen nach). Die Verschreibung von
Antibiotika war 56% wenn der RDT für Malaria negative war und 16% wenn der
RDT postiv war (p <0.001). Die Akzeptanz für IPTi scheint in melanesischen
Bevölkerung gut zu sein.
Schlussvolgernd
Die Verwendung von RDT und Artemether / Lumefantrin ist eine sichere und
wirksame Strategie für die Verwaltung der Malariafälle in PNG und könnte sehr
leicht realisiert werden. IPTi hat seine Wirksamkeit demonstriet, sowohl Pf und
Pv Episoden zu reduzieren. Allerdings ist die offensichtliche Abwesenheit von
Vorteilen auf die gesamte Morbidität und auf schwere Krankheiten ein Anliegen,
und mildert das Interesse der Durchführung dieser Intervention in PNG. Darüber
hinaus gibt es andere Faktoren, wie eine niedrige EPI Berichterstattung und die
sich rasch verändernde Malaria endemizität durch die kürzliche Einführung in
PNG von Insektiziden behandelte Moskitonetze (ITN) und Artemisinin-
Kombinationstherapien (ACT), die die potenziellen Vorteile der IPTi in PNG
gefährden könnten
