Littérature scientifique sur le sujet « FISICA SOLARE »
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Articles de revues sur le sujet "FISICA SOLARE"
1
Yuliarita, Emi. « Pengaruh Pencampuran Kerosin dalam Minyak Solar 48 terhadap Perubahan Sifat- Sifat Fisika/Kimia Utama Minyak Solar48 ». Lembaran publikasi minyak dan gas bumi 44, no 2 (8 février 2022) : 204–13. http://dx.doi.org/10.29017/lpmgb.44.2.601.
Texte intégralRésumé :
Pencampuran kerosin ke dalam minyak Solar 48 akan mempengaruhi sifat-sifat fisika/kimiaminyak Solar 48 secara menyeluruh. Untuk melihat sejauh mana perubahan sifat-sifat fisika/kimia minyak Solar 48 akibat masuknya kerosin ini maka dilakukan penelitian pengaruhpencampuran kerosin dalam minyak Solar 48 terhadap perubahan karakteristik fisika/kimia minyakSolar 48. Metodologi yang digunakan adalah metode pencampuran langsung (direct blending)dengan volume pencampuran 10%, 20%, 30% dan 40%. Hasil penelitian menunjukkan bahwapencampuran 10% volume kerosin dalam minyak Solar 48 dapat menyebabkan penurunan beberapasifat-sifat fisika/kimia utama minyak solar seperti angka setana, viskositas kinematik, titik nyala,kandungan sulfur dan lubrisitas. Penurunan sifat-sifat fisika/kimia akibat penambahan 10% volumekerosin dalam minyak Solar 48 masih dapat memenuhi Spesifikasi Minyak Solar 48 yangditetapkan Pemerintah.
2
Sari, Liawati Permata, Siti Patimah et Ajo Dian Yusandika. « Pengembangan Scrapbook Sebagai Media Pembelajaran Fisika ». Indonesian Journal of Science and Mathematics Education 2, no 2 (29 novembre 2019) : 270–76. http://dx.doi.org/10.24042/ijsme.v2i2.4367.
Texte intégralRésumé :
Abstract: This study aims to determine the feasibility of learning media Scrapbook on Solar System materials, as well as to know the response of teachers and learners to the development of learning media Scrapbook on Solar System materia ls.This research is a type of research and development (R & D). The steps of research and development are guided by Brog and Gall model with seven stages. This research was conducted at UIN Raden Intan Lampung, SMPN 21 Bandar Lampung, SMPN 13 Bandar Lampung, and Mts Muhammadiyah Bandar Lampung. The instrument of data collection used is questionnaire or questionnaire. Technique of collecting data using questionnaire with Likert scale. Data analysis techniques used are qualitative descriptive analysis techniques and descriptive statistical analysis. Media feasibility results based on the assessment of media experts and material experts are included in very good criteria. As well as the outcomes of teacher and learner responses through small group trials and field trials were assessed with very good criteria. Scrapbook learning media on the material of the Solar System as a whole received an assessment that is included in the criteria very well, so it is worthy to be used as a medium of learning.Abstrak: Penelitian ini bertujuan untuk mengetahui kelayakan media pembelajaran Scrapbook pada materi Tata Surya, serta mengetahui respon guru dan peserta didik terhadap pengembangan media pembelajaran Scrapbook pada materi Tata Surya. Penelitian ini merupakan jenis penelitian dan pengembangan (R&D). Langkah-langkah penelitian dan pengembangan berpedoman pada model Brog and Gall dengan tujuh tahapan. Penelitian ini dilaksanakan di UIN Raden Intan Lampung, SMPN 21 Bandar Lampung, SMPN 13 Bandar Lampung, dan Mts Muhammadiyah Bandar Lampung. Instrumen pengumpulan data yang digunakan adalah angket atau kuesioner. Teknik pengumpulan data menggunakan angket dengan skala Likert. Teknik analisis data yang digunakan yaitu teknik analisis deskriptif kualitatif dan analisis statistik deskriptif. Hasil kelayakan media berdasarkan penilaian ahli media dan ahli materi termasuk dalam kriteria sangat baik. Serta hasil respon guru dan peserta didik melalui uji coba kelompok kecil dan uji coba lapangan memperoleh penilaian dengan kriteria sangat baik. Media pembelajaran Scrapbook pada materi Tata Surya secara keseluruhan memperoleh penilaian yang termasuk dalam kriteria sangat baik, sehingga layak digunakan sebagai media pembelajaran.
3
Yuliarita, Emi. « PENGARUH PENGGUNAAN LCO SEBAGAI KOMPONEN MINYAK SOLAR TERHADAP SIFAT-SIFAT FISIKA/KIMIA MINYAK SOLAR ». Lembaran publikasi minyak dan gas bumi 39, no 1 (21 février 2022) : 17–25. http://dx.doi.org/10.29017/lpmgb.39.1.653.
Texte intégralRésumé :
Meningkatnya populasi kendaraan bermotor bermesin diesel di Indonesia, dan ditambah dnegan banyaknya industri-industri yang benyak menggunakan minyak solar sebagai bahan bakarnya, menyebabkan kebutuhan minyak solar dalam negeri meningkat dari tahun ke tahun. sementara itu persediaan minyak solar dalam negeri tidak mencukupi sehingga untuk memenuhi kebutuhan tersebut Indonesia terpaksa mengimpor minyak solar.
4
Rahman, Rosdiana Afifah, et Sudarti Sudarti. « ANALISIS KEMAMPUAN BERPIKIR KRITIS MAHASISWA PENDIDIKAN FISIKA SEMESTER 3 TENTANG PEMANFAATAN TEKNOLOGI SOLAR CELL TERHADAP LINGKUNGAN ». Jurnal Inovasi Penelitian dan Pembelajaran Fisika 2, no 1 (31 janvier 2021) : 10. http://dx.doi.org/10.26418/jippf.v2i1.44530.
Texte intégralRésumé :
This article aims to analyze students' understanding of the purpose of solar cell technology. Because the role of students is very important in developing one of the renewable energies that is solar cells. There are still many people who have not seen other benefits from the sun, as well as ways to use solar energy for other processes, such as the use of solar cells in households and so on. Most of humans have not seen other ways and benefits of solar energy. So that to socialize the use of solar cell technology, students need to understand how important solar energy is as a renewable energy and how to use it. The method used in this study used quantitative descriptive, with the sample of 2019 class of physics education students.Keywords: Solar cell, Environment, Renewable.
5
Susilawati, Susilawati, et Intan Wulan Sari. « PEMBELAJARAN FISIKA BERBANTUKAN MEDIA SOSIAL FACEBOOK DAN DAMPAKNYA TERHADAP HASIL BELAJAR FISIKA ». Jurnal Pendidikan Fisika 7, no 1 (29 mars 2019) : 1. http://dx.doi.org/10.24127/jpf.v7i1.1788.
Texte intégralRésumé :
Era teknologi saat ini mebutuhkan kemampuan menggunakan pembelajaran yang memadukan pemanfaatan informasi teknologi dan komunkasi untuk meningkatkan hasil belajar. Sehingga pemanfaatan produk teknologi dalam pembelajaran perlu mendapat perhatian serius. Tujuan penelitian ini untuk mengetahui pengaruh pembelajaran berbantukan media sosial facebook terhadap hasil belajar fisika pada topik tata surya. Metode yang diguanakan dalam penelitain ini adalah kuasi eksperimen dengan desain one group pretest posttest. Penelitian ini dilakukan di MTsN Rukoh Banda Aceh pada siswa kelas VII dengan total sampel 59 siswa. Melalui metode random sampling terpilih kelas VIIA sebagai kelas eksperimen yang diberi perlakuan pembelajaran berbantukan media sosial facebook. Sedangkan kelas VIID terpilih sebagai kelas kontrol yang diajarakan dengan metode diskusi tanya jawab. Teknik pengolahan data melalui uji t dengan aplikasi SPSS versi 20. Setelah dilakukan analisis persyaratan diperoleh data bahwa kedua kelas memenuhi syarat normalitas dan homogenitas. Hasil uji t diperoleh nilai t hitung 25,58 dimana t tabel 16,9 maka t tabel < t hitung yaitu 16,9 < 25.58 sehingga Ho ditolak dan Ha diterima. Hasil ini menunjukkan terdapat pengaruh pembelajaran berbantukan media sosoal facebook terhadap hasil belajar siswa. Berdasarkan hasil Paired Samples Test dan Paired samples correlations diperoleh nilai sig (2- tailed) 0.000 < 0,05 menunjukkan adanya pengaruh signifikan pembelajaran berbantukan jejaring social facebook terhadap hasil belajar fisika pada topik tata surya.The current era of technology requires the ability to use learning that combines the use of information technology and communication to improve learning outcomes. So that the use of technology products in learning needs serious attention. The purpose of this study was to determine the effect of Facebook social media assisted learning on the results of learning physics on the topic of the solar system. The method used in this research is quasi-experiment with the design of one group pretest posttest. This research was conducted at Rukoh Banda Aceh MTsN in class VII students with a total sample of 59 students. Through the random sampling method selected the VIIA class as the experimental class which was given a learning treatment assisted by social media Facebook. While the VIID class was chosen as the control class taught by the question and answer discussion method. Data processing techniques through t-test with SPSS version 20. After the requirements analysis, the data obtained that the two classes meet the requirements for normality and homogeneity. The results of the t test obtained t count 25.58 where t table 16.9 then t table <t count is 16.9 <25.58 so Ho is rejected and Ha is accepted. These results indicate that there is an effect of learning assisted by social media Facebook on student learning outcomes. Based on the results of Paired Samples Test and Paired samples correlations, the value of sig (2- tailed) 0,000 <0,05 indicates that there is a significant influence of learning assisted by Facebook social networking on the results of learning physics on the topic of the solar system.
6
Yuliarita, Emi. « Pengujian kinerja terbatas Minyak Solar Bertitik Nyala 55oC dan 52oC pada Bangku Uji Multisilinder ». Lembaran publikasi minyak dan gas bumi 45, no 2 (1 mars 2022) : 165–73. http://dx.doi.org/10.29017/lpmgb.45.2.695.
Texte intégralRésumé :
Dalam penelitian terdahulu telah dilakukan pembuatan bahan bakar minyak solar 48 bertitiknyala 55oC dan 52oC melalui cutting distillation. Dari hasil analisis sifat-sifat fisika/kimia masingmasingminyak solar bertitik nyala 55oC dan 52oC yang didapatkan, dapat memenuhi spesifikasiminyak solar 48 yang di tetapkan pemerintah sesuai dengan surat keputusan Dirjen Migas No.3675 K/24/DJM/2006 tanggal 17 Maret 2006. Selanjutnya untuk melihat kinerja (performance)dari masing-masing bahan bakar tersebut maka dilakukan pengujian kinerja terbatas terhadapmasing-masing bahan bakar minyak solar bertitik nyala 55oC dan 52oC pada bangku uji multisilinder(Multisylinder Test Bench) dengan menggunakan mesin diesel Isuzu 4JA1) pada tiga kategoribeban. Hasil uji kinerja secara keseluruhan memperlihatkan bahwa minyak solar bertitik nyala55oC dan 52oC sedikit lebih kecil dari minyak solar bertitik nyala 60oC. Namun emisi gas buangkepekatan asap/opasitas minyak solar bertitik nyala 55oC dan 52oC jauh lebih rendah disbandingminyak solar bertitik nyala 60oC.
7
Yuliarita, Emi. « Pembuatan Bahan Bakar Minyak Solar 48 Bertitik Nyala Minimum 550C dan 520C Melalui Cutting Distillation ». Lembaran publikasi minyak dan gas bumi 45, no 1 (1 mars 2022) : 25–31. http://dx.doi.org/10.29017/lpmgb.45.1.679.
Texte intégralRésumé :
Pada saat ini batasan titik nyala yang ditentukan untuk minyak Solar 48 di Indonesia adalahminimum 60°C, yang lebih tinggi dibandingkan dengan negara-negara lain. Oleh karena itu penelitianini bertujuan untuk membuat minyak Solar 48 dengan titik nyala minimum 55oC dan 52oC denganmenggunakan metode cutting distillation. Proses cutting distillation dilakukan terhadapcampuran 50:50 minyak tanah dan minyak solar pada temperatur penguapan distilat berkisarantara 10% sampai 40% dari volume distilat. Sisa campuran bahan bakar yang diperoleh daripemotongan distilasi yang mempunyai angka setana paling mendekati 48 digunakan sebagaikomponen dasar untuk pembuatan minyak Solar 48 bertitik nyala 55oC dan 52oC. Kemudianfraksi nafta digunakan untuk membuat penyesuaian titik nyala.Berdasarkan hasil uji sifat-sifat fisika/kimia minyak solar 48 bertitik nyala 55oC dan 52oCyang dihasilkan dalam penelitian ini adalah sesuai dengan spesifikasi minyak Solar 48 yangberlaku di Indonesia sebagaimana diatur dalam Surat Keputusan Dirjen Migas No. 3675 K/24/DJM/2006 tanggal 17 Maret 2006.
8
Mulyadi, Eko. « Pengembangan Media Pembelajaran Efek Fotolistrik pada Pembelajaran Fisika di SMK ». Ideguru : Jurnal Karya Ilmiah Guru 7, no 2 (1 mai 2022) : 206–11. http://dx.doi.org/10.51169/ideguru.v7i2.361.
Texte intégralRésumé :
Pengembangan media pembelajaran efek fotolistrik berupa serangkaian solar sel, bertujuan untuk: 1) studi kelayakan media pembelajaran efek fotolistrik, 2) mempermudah pemahaman siswa tentang efek fotolistrik, 3) membuat siswa menyukai pembelajaran efek fotolistrik dan 4) mengukur besarnya peran media pembelajaran solar sel dalam membantu pemahaman siswa. Proses pengembangan menggunakan model Borg & Gall: 1) Potensi (Masalah), 2) pengumpulan data, 3) desain produk validasi, 4) revisi, 5) uji coba, 6) revisi, 7) produk yang dihasilkan.yang dimulai dari desain rancangan dengan menggunakan 4 panel surya disusun pararel dihubungkan dengan kabel 2 buah kabel positif dan negatif, ke hambatan, kapasitor dan diode, kemudian ke lampu LED, produk dari desain di rangkai, hasilnya dinilaikan kepada ahli media, ahli materi dan pengguna, penilaian dari ahli media, ahli materi dan pengguna di rekapitulasi, untuk mengetahui kelayakan, hasil masukan dan saran untuk perbaikan produk. Hasil penilaian diperoleh rata-rata dari ahli media sebesar 4,00 kategori baik, ahli materi sebesar 4,40 kategori sangat baik dan pengguna diperoleh rata-rata 3,85 kategori baik dan media layak untuk digunakan, siswa yang memahami materi efek fotolistrik dengan media sebesar 58%, siswa yang menyukai pembelajaran efek fotolistrik dengan media 27% amat baik, 35% baik, siswa menilai peran media pembelajaran efek fotolistrik, 46% amat baik dan 35% baik.
9
Shahid, Muhammed, Rizwan Aslam Butt et Attaullah Khawaja. « Fiscal- and Space-Constrained Energy Optimization Model for Hybrid Grid-Tied Solar Nanogrids ». Energies 15, no 21 (31 octobre 2022) : 8080. http://dx.doi.org/10.3390/en15218080.
Texte intégralRésumé :
Due to rising fossil fuel costs, electricity tariffs are also increasing. This is motivating users to install nanogrid systems to reduce their electricity bills using solar power. However, the two main constraints for a solar system installation are the initial financial investment cost and the availability of space for the installation of solar panels. Achieving greater electricity savings requires more panels and a larger energy storage system (ESS). However, a larger ESS also increases the electricity bill and reduces the available solar power due to higher charging power requirements. The increase in solar power leads to the need for more space for solar panel installation. Therefore, achieving the maximum electricity savings for a consumer unit requires an optimized number of solar panels and ESS size within the available financial budget and the available physical space. Thus, this study presents a fiscal- and space-constrained mixed-integer linear programming-based nanogrid system model (FS-MILP) designed to compute the optimal number of solar panels and ESS requirements, and the daily electricity unit consumption and savings. The proposed model is also validated through an OMNET++-based simulation using real-time solar irradiance and residential load values of one year for the city of Karachi, Pakistan. The investigation results show that a maximum of 1050 electricity units can be saved and exported to the main power grid within the maximum financial budget of PKR 1,000,000/-.
10
Detoni, Alessandra Maria, Neuza Francisca Michelon Herzog, Tatiane Ohland, Tailene Kotz et Edmar Clemente. « Influência do sol nas características fisicas e químicas da tangerina 'Ponkan' cultivada no oeste do Paraná ». Ciência e Agrotecnologia 33, no 2 (avril 2009) : 624–28. http://dx.doi.org/10.1590/s1413-70542009000200041.
Texte intégralRésumé :
A 'Ponkan' (Citrus reticulata Blanco) é uma das tangerinas mais produzidas no Brasil e muita apreciada pelo consumidor brasileiro. Tendo em vista a sua alta aceitação, há preocupação em se produzir frutos de boa qualidade. Entre os fatores que interferem na qualidade dos frutos podemos citar, como exemplo, a radiação solar. Objetivou-se, neste trabalho, avaliar as características físicas e químicas de frutos de tangerina 'Ponkan', cultivados no oeste do Paraná e colhidos em dois quadrantes da planta, um de maior incidência solar (leste-oeste) e outro de menor incidência (norte-sul). Para as análises físicas determinou-se: o peso do fruto, da casca e dos gomos, diâmetro transversal e longitudinal. Nas análises químicas foram avaliados: o pH, teor de sólidos solúveis totais (SST), acidez total titulável (ATT), relação SST/ATT e teor de ácido ascórbico. Pôde-se verificar pelos resultados obtidos que os frutos desenvolvidos no quadrante leste-oeste das plantas, onde ocorre maior incidência solar, apresentaram maior peso (212,86 g) e diâmetro longitudinal (74,42 mm) quando comparados com frutos do quadrante de menor incidência solar (180,30 g e 67,75 mm, respectivamente). Porém, nas características químicas não observaram diferenças que pudessem interferir no sabor dos frutos.
Thèses sur le sujet "FISICA SOLARE"
1
Cavalazzi, Gianmarco. « Fisica delle celle fotovoltaiche modelli e prospettive di ricerca ». Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/24338/.
Texte intégralRésumé :
La presente tesi costituisce un lavoro di rassegna sugli ultimi risultati e sulle prospettive di ricerca relative alle celle fotovoltaiche.
Dopo un’introduzione sulle proprietà di interesse della radiazione elettromagnetica e dello spettro solare, si illustrano i meccanismi fisici di interazione radiazione-materia alla base dell’effetto fotovoltaico. Si descrivono poi il principio di funzionamento e i parametri caratteristici delle celle fotovoltaiche, e si discutono alcune strategie adottate per migliorare l’efficienza di conversione dell’energia solare in energia elettrica. Si presentano infine alcune delle tecnologie e architetture più recenti di celle solari: le celle fotovoltaiche a perovskite e le celle fotovoltaiche tandem silicio-perovskite, che hanno dimostrato grandi potenzialità di miglioramento delle prestazioni e risultano particolarmente interessanti per le elevate efficienze raggiunte e i bassi costi di produzione.
2
Albertazzi, Clarissa. « Studio di celle fotovoltaiche di terza generazione : celle tandem ». Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8942/.
Texte intégralRésumé :
Il fotovoltaico (FV) costituisce il modo più diretto di conversione dell’energia solare in energia elettrica e si basa sull’effetto osservato da Becquerel nel 1839. Si può affermare che tale effetto è rimasto una curiosità di laboratorio dalla metà del XIX secolo fino al 1954, quando la prima cella solare in silicio con un’efficienza di conversione del 6% fu costruita ai Laboratori Bell. Da allora la ricerca in questo settore ha sperimentato una crescita costante ed oggi si può contare su tecnologie mature, in grado di sviluppare alte prestazioni in via di ulteriore miglioramento. Le celle tandem costituiscono ora il migliore esempio di dispositivi fotovoltaici in grado di convertire buona parte della potenza irraggiata dal sole. Aumentare l’efficienza con le celle tandem significa sfruttare le differenti lunghezze d’onda dello spettro solare. Questi dispositivi sono infatti costruiti impilando semiconduttori, disponendoli dal basso in modo crescente secondo i loro valori di energia di gap.
A partire dall’analisi delle caratteristiche principali della radiazione solare e del principio di funzionamento delle celle fotovoltaiche, questo lavoro si propone di mettere in evidenza le potenzialità della tecnologia a multigiunzione, che ha già dimostrato rilevanti capacità di ottimizzazione delle prestazioni delle celle solari, facendo ben sperare per il futuro.
3
Franceschetti, Paolo <1981>. « Energie rinnovabili e microgenerazione distribuita : serra solare ad evaporazione ». Doctoral thesis, Università Ca' Foscari Venezia, 2013. http://hdl.handle.net/10579/4658.
Texte intégralRésumé :
In un contesto internazionale di ricerca focalizzato allo sviluppo di nuove tecnologie basate su energie alimentate da fonti rinnovabili, un settore di sempre maggiore interesse è lo sviluppo d’impianti di microgenerazione legati all’acqua. In questo settore si pone il presente studio, il quale vuole apportare un contributo innovativo all’ottimizzazione dei sistemi di desalinizzazione/depurazione delle acque sfruttando unicamente la radiazione solare.
Lo stato dell’arte di questi sistemi, denominati serre solari, è stato in prima istanza analizzato al fine di comprenderne le potenzialità e i limiti dal punto di vista fisico e di efficienza. Si sono quindi sviluppati e sperimentate nuove configurazioni che hanno portato a significativi miglioramenti delle prestazioni. Sulla base dei risultati dei primi test, è stato sviluppato poi il calcolo exergetico dell’intero sistema. Attraverso sperimentazioni circa la tipologia dei materiali da utilizzare per la costruzione delle serre solari e le modellizzazioni termodinamiche e fluidodinamiche, si è giunti quindi ad un ulteriore sviluppo dei sistemi. I miglioramenti apportati hanno permesso un’efficienza del sistema depurativo maggiore rispetto allo stato dell’arte. Una volta consolidato il sistema, è stata approfondita l’analisi volta ad individuare in quali aree del pianeta questi sistemi possano essere maggiormente applicabili, in funzione delle condizioni climatiche (modello geo-spaziale – GSI) e delle condizioni antropiche (indice socio-economico –SEI)In an International context of research focused on the development of new technologies based on energy supplied by renewable sources, the development of micro-water treatment plants is of increasing interesting. The current study fits into this perspective with the aim to provide an innovative tool for the optimization of the desalination/water purification systems, by using only the solar radiation source. In the present study, the state of art of the systems, hereafter called solar stills, was analyzed in order to understand their potential and limits from a physical and efficiency perspective. Afterwards, new prototypes were developed and tested, resulting in a significant improvement of the solar stills’ performances. Basing on results from the first test performed, the exergetic calculation of the system was carried out. . Additionally, the experimentation on different types of materials to be used for the construction of the solar stills, in association to the thermodynamic and fluid dynamic modeling processes, allowed us to reach a further development of the systems. Such improvements leaded to a higher efficiency of the solar still, compared to the state of the art. Once the system has been consolidated, a geo-spatial analysis based on both climatic conditions (geo-spatial index - GSI ) and anthropogenic conditions (socio-economic index - SEI), has been performed with the aim to identify the areas where the developed systems were more applicable.
4
Sotte, Marco. « Design, test and mathematical modeling of parabolic trough solar collectors ». Doctoral thesis, Università Politecnica delle Marche, 2012. http://hdl.handle.net/11566/242075.
Texte intégralRésumé :
La radiazione solare alla
sua origine
è
una
fonte
di
energetica
ad
alta
exergia:
il
sole
ha
un’irradianza
pari
a
63
MW/m2.
Ma
all’arrivo
sulla
superficie
terrestre
questo
flusso
diminuisce
drasticamente.
Per
questa
ragione,
quando
si
necessita
di
elevate
temperature
o
elevate
exergie
si
adottano
sistemi
solari
a
concentrazione.
Fra
tutte
le
possibili
geometrie
i
concentratori
solari
parabolici
assiali
sono
di
gran
lunga
la
tecnologia
più
adottata.
Un
campo
di
utilizzo
dei
PTC
(parabolic
trough
collectors)
è
quello
del
calore
destinato
ai
processi
industriali:
questa
applicazione
ha
un
elevatissimo
potenziale
anche
alle
latitudini
dell’Europa
centro-‐meridionale.
Nella
presente
tesi
sono
discussi
i
risultati
di
un
progetto
di
ricerca
(PTC.project)
per
lo
studio
dei
PTC
applicati
alla
domanda
di
calore
dei
processi
industriali
o
di
altre
utenze
nell’intervallo
di
temperatura
fra
80
e
250
°C.
Sono
descritti
la
progettazione
e
la
realizzazione
di
due
prototipi
di
PTC,
con
informazioni
complete
riguardo
alle
caratteristiche
geometriche,
ai
materiali
e
ai
processi
produttivi.
Successivamente
sono
illustrati
i
risultati
di
test
preliminari
sui
prototipi,
assieme
alle
caratteristiche
di
un
banco
per
il
test
di
apparati
solari
a
temperature
comprese
fra
10
e
150
°C.
E’
poi
esposto
il
modello
matematico
sviluppato
per
descrivere
l’efficienza
ottica
e
termica
dei
concentratori,
completo
delle
routine
per
il
calcolo
della
posizione
del
sole.
Infine
è
esposto
un
ambiente
per
la
simulazione
dell’esercizio
annuale
di
un
campo
di
concentratori
accoppiato
ad
uno
specifico
profilo
di
domanda
termica.
I
risultati
suggeriscono
lo
sviluppo
di
questa
tecnologia
nel
panorama
delle
fonti
di
energia
rinnovabile
che
dovranno
essere
adottate
per
raggiungere
gli
obiettivi
energetici
ed
ambientali
fissati
in
vari
contesti
internazionali.
Ma
saranno
necessari
forti
investimenti
se
si
vorrà
imprimere
un’accelerazione
allo
sviluppo
dei
PTC
e
delle
tecnologie
solari
termiche
in
genere.Solar radiation at its origin is a high-exergy energy source: the Sun has an irradiance of about 63 MW/m2. But on the Earth’s surface solar energy flow dramatically decreases. For this reason, when high temperatures or high-exergy need to be reestablished, concentrated solar systems are adopted. Among all possible geometries, parabolic trough collectors are by far the most widespread technology. A field of usage of PTCs is in industrial process heat: this application has a dramatic potential and can be adopted at latitudes like those of central and southern europe. In this thesis the results of research project (PTC.project) for the study of PTCs in IPH and other heat demands in the temperature range from 80 to 250 °C are exposed. The design and manufacture of two prototypes are described in detail, giving complete information on geometrical characteristics, materials and manufacturing processes. Then the results of preliminary tests on the mentioned prototypes are produced, together with the characteristics of a test bench designed to determine PTCs performances with water and heat transfer oil as working fluids in a temperature range from 10 to 150 °C. Then a mathematical model, able to determine the performance of any PTC is described: the model accounts for optical and thermal losses of the collector, and also contains a routine code to calculate the solar position. In the end a simulation environment for annual analysis of the performance of a PTC applied to a specific process heat demand load is presented and the results obtained on a realistic heat demand yearly profile are described. The energetic results suggest that there could be space for this technology in the variety of renewable energies that will be needed to meet international goals in terms of energy and environment in the nearest future. But the experience acquired also suggests that investments are needed if an acceleration on the spreading of PTCs and other CSP technologies is to be realized
5
Zambolin, Enrico. « Theoretical and experimental study of solar thermal collector systems and components ». Doctoral thesis, Università degli studi di Padova, 2011. http://hdl.handle.net/11577/3422853.
Texte intégralRésumé :
Flat-plate and evacuated tube collectors are the most widely used device to convert solar radiation into heat. In conventional applications they can provide energy for domestic hot water or space heating in combination with low water temperature systems.
Testing of thermal efficiency and optimisation of these solar thermal collectors are addressed and discussed in the present work.
A new set of experimental data has been used to evaluate the performance of flat-plate and evacuated collectors at various conditions. Efficiency is measured following the standard EN 12975: standard efficiency curves, input/output energy curves and daily efficiency curves have been obtained from tests.
This approach allows a more comprehensive comparison of the effective performance of the solar thermal collectors considered here.
A simulation tool of the flat-plate thermal collector is also proposed. The numerical model permits to obtain a “virtual collector” and provides information on the predicted performance without constructing prototypes. The three-dimensional steady-state model for flat-plate solar collector is validated comparing model predictions with experimental results obtained from experimental tests on two flat-plate collectors. Measures of the temperature profile in the copper sheet, in the glass cover and in the tubes, and an infrared analysis, are used to investigate the heat losses and optical characteristics.
The numerical model has been also used to analyse comparative effects of varying design choices, with regard to geometry and materials.
The evacuated tube collectors are in principle more expensive than flat-plate collectors and they are suitable for more higher temperature systems (space heating, absorption cooling machines..). Their geometry makes more difficult to fully characterize the collector performance. A new procedure to characterize these type of collectors has been developed and described in this thesis. Efficiency tests have been performed on a U-tube evacuated tubular collector, using a cylindrical absorber, both with and without external CPC (compound parabolic concentrator) reflectors.
Experimental results have been used to validate the new procedure and to provide information on the improvement of collectors’ performance obtained through the use of external CPC reflectors.I collettori solari termici maggiormente impiegati per convertire la radiazione solare in calore sono i collettori a tipologia piana e a tubi evacuati. Nelle applicazioni convenzionali essi vengono utilizzati per la produzione di acqua calda sanitaria o riscaldamento domestico in combinazione con sistemi a bassa temperatura. Prove d’efficienza termica ed ottimizzazione di questi dispositivi solari sono affrontati e discussi in questa tesi. Nuove prove sperimentali in varie condizioni sono state effettuate su collettori piani vetrati e a tubi evacuati per effettuare una nuova analisi comparativa. L’efficienza è stata misurata secondo le indicazioni della normativa europea EN 12975 ed inoltre si sono ricavate curve input-output e di efficienza media giornaliera. Questo approccio permette un confronto più ampio delle prestazioni effettive dei collettori solari considerati. Uno strumento di simulazione delle prestazioni dei collettori a geometria piana è anche proposto. Il modello numerico permette di ottenere un “collettore virtuale” e fornisce informazioni sulle prestazioni di un collettore senza costruirne un prototipo funzionale. Il modello tridimensionale stima le prestazioni di un collettore a geometria piana in condizioni stazionarie ed è stato validato confrontando le prestazioni stimate con i risultati sperimentali ottenuti su due collettori diversi. Misure di temperatura della piastra assorbente, della copertura vetrata, dei tubi dell’arpa ed analisi all’infrarosso sono stati utilizzati per investigare le dispersioni termiche e le caratteristiche ottiche della geometria considerata. Il modello è inoltre stato usato per analizzare gli effetti di alcune scelte progettuali riguardanti la geometria e i materiali dei componenti del collettore. I collettori solari a tubi evacuati sono in linea di principio più costosi dei collettori piani e sono idonei ad applicazioni a più alta temperatura (sistemi di riscaldamento, macchine ad assorbimento..). La loro geometria rende più difficile la caratterizzazione completa delle prestazioni del collettore. Una nuova procedura per caratterizzare questo tipo di collettori è stata sviluppata ed è qui descritta. Sono state eseguite prove sperimentali su un collettore a tubi evacuati, con tubi ad U, con assorbitore cilindrico, con e senza riflettori CPC (compound parabolic concentrator) esterni. I risultati sperimentali sono stati utilizzati per validare la nuova procedura e per fornire indicazioni sull’incremento dell’efficienza dovuto all’impiego dei riflettori CPC.
6
Maoulaoui, Khaled. « Sistemi solari stand-alone per il mantenimento della catena del freddo ». Doctoral thesis, Università Politecnica delle Marche, 2013. http://hdl.handle.net/11566/242736.
Texte intégralRésumé :
Il presente lavoro mira a fare un confronto con diverse tecnologie del freddo dal sole ‗Ice maker‘; Queste macchine potrebbero essere alimentate termicamente (solare termico-adsorbimento o assorbimento) oppure elettricamente (FV-Compressione vapore)
Il lavoro inizia con un‘introduzione che spiega i vantaggi del solar Ice maker: autonomia, salute e non tossicità, eco sostenibilità e per fattori socio economici.
Ho trattato all‘inizio l‘argomento dei captatori solari sia termici sia fotovoltaici, che serviranno ad alimentare le macchine, sono stati illustrati in seguito i cicli termodinamici delle macchine sopra citate.
Poi abbiamo studiato una macchina ad adsorbimento (metanolo-carbone attivo) alimentato da un panello solare termico. Partendo dal modello matematico e dei dati fissi e dinamici (radiazione e temperatura) inserendoli in un software dava i risultati della simulazione dinamica, poi è stata trattata l‘analisi parametrica e alla fine il dimensionamento di tutti i componenti (collettore solare, condensatore, evaporatore…)
La seconda macchina era quella ad assorbimento solare (acqua-Bromuro di litio) alimentata da panello solare termico. Facendo la stessa procedura di prima modello matematicodati dentrosimulazione dinamicarisultatianalisi parametrica (senza studiare il dimensionamento).
Invece per la terza macchina si tratta compressione di vapore (R-600a) alimentato con panello policristallino e motore DC. Facendo la stessa procedura appena citata.
Il confronto finale tra queste tre macchine è stato fatto basandoci su indici di confronto (quantità ghiaccio al giorno/ superfice panello, rendimento, minime temperature raggiunte…) per stabilirne che quella a adsorbimento sia la migliore.
Il passo successivo è oltrepassare la simulazione dinamica, e Progettare/installare le tre macchine nella stessa zona climatica (Africa subsahariana) e studiare realmente il funzionamento in sito e stabilirne quale macchina sia la migliore nelle stesse condizioni operative.The present work aims to make a comparison between different sun‘s cold technologies ―Ice maker ―; These machines could be thermally powered by (solar thermal energy adsorption or absorption) or electrically (FV- vapor Compression) The work begins with an introduction, that explains the advantages of solar Ice maker: Self-sufficiency, Health and non-toxicity, Ecological sustainability, Social and Economic factors. I mentioned at the beginning the topic of the PV and thermal solar collectors, which will be used to drive these machines, and then i illustrated in the thermodynamic cycle of the machines mentioned above. Then i studied the adsorption machine (methanol-activated charcoal) powered by a solar thermal Panel. Starting from a mathematical model and fixed and dynamic data (temperature and radiation) inserting them in a software that gives us the dynamic simulation results, then it was discussed the parametric analysis and design of all components (solar collector, condenser, evaporator, ...) The second machine was the solar absorption (water-lithium bromide) powered by solar thermal Panel. Doing the same procedure of first mathematical model input data dynamic simulationresultsparametric analysis (without studying the machine design). For the third machine the vapor compression (R-600a) powered by polycrystalline Panel and DC motor. Doing the same procedure just over mentioned. The final comparison between these three machines was done based on comparing index (Ice quantity per day/Panel surface, STR, Lowers temperatures reached ...) to find that the best machine is the solar adsorption. The next step is to go beyond dynamic simulation, and to Design/install these three machines in the same climate zone (sub-Saharan Africa) studying the effective machines run and to establish which one is the best in the same operating conditions.
7
Orlando, Andrea. « Multispacecraft observations of Coronal Mass Ejections ». Doctoral thesis, Università di Catania, 2012. http://hdl.handle.net/10761/990.
Texte intégralRésumé :
The Sun-Earth environment is strongly influenced by the coupling level between the Earth magnetosphere and the interplanetary magnetic field. The latter is closely related to the solar wind, a flux of plasma continuously flowing from the Sun and propagating in the interplanetary space medium. This plasma is constituted by electrons, protons and heavier particles, and propagates with a speed of 400-800 km/s, reaching Earth in 2.4-4.6 days. A sudden increase of the solar wind's speed is achieved by two types of phenomena: flares and Coronal Mass Ejections (CMEs).
In this context, this thesis concerns the study of the physical processes that lie at the base of the CME formation and of their effects on the Sun-Earth environment. Such an investigation can be done utilizing data taken from satellites that study solar wind, interplanetary magnetic field, flares and CMEs.
8
RONCHI, ALESSANDRA. « Hybrid and Nanostructured materials for low power photon upconversion based on triplet-triplet annihilation ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2022. http://hdl.handle.net/10281/370864.
Texte intégralRésumé :
Durante il dottorato ho investigato il processo fotofisico di "upconversion" assistito da annichilazione tripletto-tripletto (TTA-UC) tramite studi di spettroscopia in sistemi profondamente differenti gli uni dagli altri. In TTA-UC radiazione ad alta energia è emessa dalla ricombinazione radiativa dello stato di singoletto eccitato di una molecola emettitore, popolato precedentemente dall'annichilazione dei tripletti di due emettitori. Un sensibilizzatore immagazzina la luce incidente a bassa energia e trasferisce l'eccitazione agli emettitori tramite trasferimento di energia alla Dexter. Poiché il suo funzionamento si basa su tripletti mestastabili, TTA-UC può essere altamente efficiente anche in condizioni di luce non coerente e a bassa energia. Come tale, è particolarmente adatto per dispositivi che sfruttano l'energia solare poiché è in grado di aumentarne l'efficienza di conversione limitando le perdite per trasmissione. Mi sono concentrata su due problemi importanti che tuttora limitano l'impiego di materiali che attuano TTA-UC (upconverters), ossia la limitata capacità di immagazzinare energia dei comuni sensibilizzatori organici e le scarse prestazioni di TTA-UC in upconverters a stato solido, i quali sono più adatti per applicazioni tecnologiche rispetto a sistemi liquidi. Per risolvere il primo problema ho investigato sensibilizzatori ibridi, composti da nanostrutture a semiconduttore decorate con molecole organiche, con ampio assorbimento. Nanocristalli di CdSe drogati con cationi d'oro e decorati con acido antracenico carbossilico si sono dimostrati essere sensibilizzatori ibridi efficienti ed innovativi. Il drogante introduce nel gap energetico dei nanocristalli livelli localizzati su cui le lacune si localizzano sulla scala dei picosecondi, più velocemente dell'estrazione di lacune sul livello HOMO dei leganti. Con tale strategia ho raggiunto l'efficienza di UC del 12%, record per sistemi ibridi. Ho poi mostrato come le proprietà superficiali e fotofisiche di nanoplatelets di CdSe le rendano ottimali candidati in sensibilizzatori ibridi. Ho mostrato che il ricoprimento delle superfici non è omogeneo, ma procede ad isole e l'interazione di "π- π stacking" porta alla formazione di aggregati sulle superfici delle nanoplatelets, con il risultato di ridurre l'energia dei tripletti dei leganti con profonde ripercussioni sulle prestazioni di TTA-UC e sulla scelta della specie emettitrice. Riguardo al secondo problema, ho studiato due upconverters a stato solido, polimeri vetrosi nanostrutturati che mostrano proprietà macroscopiche simili ma realizzati con tecniche differenti. Essi presentano domini liquidi di dimensione inferiore a 50 nm dove le specie che attuano TTA-UC si accumulano, racchiuse in una matrice rigida polimerica che fornisce protezione da ossigeno e qualità ottica eccellenti e stabilità a lungo termine. Il confinamento molecolare permette di aumentare la densità locale di eccitoni aumentando l'efficienza di UC a basse potenze grazie alle ridotte distanze intermolecolari e all'attivazione del regime di TTA-UC confinato.Ho inoltre studiato un nuovo emettitore derivato da perilene, realizzato con lo scopo di aumentarne l'efficienza di fluorescenza. Grazie a questo emettitore ho raggiunto l'efficienza record di UC di 42%, dovuta proprio alla struttura molecolare dell'emettitore che permette di limitare la formazione di aggregati, garantendo un'eccellente efficienza di generazione di singoletti tramite TTA. Infine, ho presentato una prospettiva riguardo alle prestazioni che possono essere raggiunte combinando le due tematiche trattate, ossia inserendo sensibilizzatori ad ampio assorbimento in polimeri nanostrutturati. Trovando il giusto compromesso tra taglia dei domini liquidi e distribuzione dell'energia di eccitazione si raggiungerebbe la massima efficienza di UC a potenze minori dell'irradianza solare, promuovendo lo sviluppo di upconverters a stato solido per tecnologie a energia solareIn my PhD project, I investigated the photophysical process of photon upconversion assisted by triplet-triplet annihilation (sTTA-UC) through spectroscopy studies in a variety of systems, profoundly different on many levels. In sTTA-UC high energy radiation is emitted from the fluorescent recombination of the excited singlet of an emitter molecule, previously populated via annihilation of the metastable triplet states of two emitters. This is a sensitized process since a sensitizer is necessary to harvest the low energy incident light and to transfer the stored energy to the emitters via Dexter energy transfer. Because its functioning relies on long-lived metastable triplets, this process can be highly efficient also under low power, noncoherent light. As such, sTTA-UC is particularly suited for solar applications as it can increase the conversion efficiency by reducing transmission losses. During my studies, I focused on addressing two crucial issues that still limit the application of upconverters in solar technologies, i.e. the limited storage ability of common organic sensitizers and the poor sTTA-UC performance in solid-state upconverters, which are intrinsically better suited than liquid solutions for technological applications. To solve the first problem, I investigated hybrid sensitizers, composed of semiconductor nanostructures decorated with conjugated organic ligands characterized by broadband absorption. CdSe nanocrystals (NCs) doped with gold cations and decorated with 9-anthracene carboxylic acid demonstrated to be efficient innovative broadband hybrid sensitizers. The doping strategy inserts into the NCs energy gap localized hole-accepting states where the holes localize on the picosecond timescale, outpacing hole transfer to the ligand HOMO. With this strategy, I achieved the UC efficiency of 12%, the record performance obtained so far for hybrid upconverters. I then discussed how the CdSe nanoplatelets surface and photophysical properties make them potential optimal light harvesters. My studies on the nanoplatelets-to-ligands energy transfer dependency on the surface ligand density revealed that the surface coverage is not homogeneous but proceeds in an island-like way promoted by π- π stacking and results in the formation of ligands aggregates on the nanoplatelets surfaces, which causes a redshift of the ligand triplet energy with critical repercussions on the sTTA-UC performance and on the emitter selection. To address the second issue, I investigated two solid-state upconverters, i.e. nanostructured glassy polymers that show similar macroscopic properties but fabricated via different approaches. They both feature liquid droplets of mean size less than 50 nm where the upconverting dyes accumulate, embedded in a rigid polymer matrix that grants excellent oxygen protection and optical quality and long-term stability. The dyes confinement allows to increase the effective local excitons density resulting in an enhanced UC efficiency at low excitation intensities, thanks to the reduced intermolecular distances and the activation of the confined sTTA-UC regime. I also introduced a new perylene derivative as emitter, specifically designed to prevent molecular aggregation to maximize its fluorescence efficiency. By employing this emitter, I achieved the record UC efficiency of 42%, which directly stems from the emitter molecular structure, as it limits the formation of aggregates, while guaranteeing excellent singlet generation efficiency upon TTA. I finally presented a perspective of the performances that can be achieved by combining the two topics considered, i.e. loading broadband sensitizers in nanostructured polymers. I highlighted that if the best trade-off between nanostructure size and energy distribution is met the maximum UC efficiency can be achieved at excitation powers orders of magnitude lower that the solar irradiance, therefore promoting the development of real-world solid-state upconverters.
9
Emmi, Giuseppe. « ANALISI TEORICA E SPERIMENTALE DI SISTEMI SOLARI PER LA CLIMATIZZAZIONE E LA PRODUZIONE DI ACQUA CALDA SANITARIA DI EDIFICI RESIDENZIALI ». Doctoral thesis, Università degli studi di Padova, 2010. http://hdl.handle.net/11577/3427018.
Texte intégralRésumé :
The aim of this work is the analysis of the application of solar thermal systems for combining heating, cooling and hot water production. The most important topic of this work is therefore the use of renewable solar energy for the reduction of energy use in civil buildings. The use of solar radiation to produce electrical energy has not been investigated in this context. In particular, measurements of the effciency of solar thermal system installed in a residential dwelling in Treviso and results of solar cooling system simulations coupled with radiant systems are presented.
The first part of the thesis presents the current status of the solar thermal market in Europe and in the World, and expected trends for the future.
The first case study regards the energy efficiency of a residential building with solar thermal system for heating and domestic hot water production. Afterwords a dynamic model of the building and the system was developed in the software TRNSYS, in order to evaluate the performance of the system depending on with different parameters, such as collector area and tank volume.
The second part of the thesis regards solar cooling systems equipped with absorption machines. This part starts with a short introduction of the absorption technology. Then, the results of a study for a patent prototype system are summed up. This system is a “Plug&Play” machine for residential and office buildings. In the frame of this study the design of each part of the system has been carried out by the use of dynamic models, by applying simulations to the proposed system, in a typical dwelling. This model describes the application of the proposed system both in a residetial building and in a office building. Different types of radiant system are used for checking the indoor comfort and for evaluating the best solution as terminal unit.
The last part of this thesis is based on the previous study. At first the design of a thermal chamber for a company producing radiant ceilings was developed. This chamber will be used to measure the performance of cooling radiant systems and for didactic purposes. After that, a case study consisting in solar collectors, coupled with an absoption chiller applied to a radiant ceiling has been investigated. This case evaluates the energy provided for heating, cooling and domestic hot water production for a residential dwelling. The results of the simulations are presented for four different climatic zones.Il presente lavoro verifica l’applicazione dell’energia solare termica ai fini della climatizzazione combinata alla produzione di acqua calda sanitaria nel settore civile al fine di ridurne i consumi energetici. In particolare è stata analizzata una serie di studi derivanti da misure in opera delle prestazioni di funzionamento di un impianto solare termico installato in un’abitazione residenziale nella provincia di Treviso e da simulazioni dinamiche del sistema edificio–impianto sia per il riscaldamento che per il raffrescamento. L’obiettivo principale è verificare, o comunque prevedere, quali siano i margini di risparmio ottenibili dallo sfruttamento della tecnologia appositamente creata per l’utilizzo della radiazione solare solamente da punto di vista termico in sistemi attivi. In tale contesto infatti non verrà trattato l’aspetto relativo alla produzione elettrica fotovoltaica, che assieme ai sistemi solari termici ha avuto una grande diffusione soprattutto negli ultimi anni grazie ad incentivi di natura pubblica. Nella prima parte del lavoro si analizza quale sia lo stato attuale del mercato del solare termico nei vari Paesi europei e del mondo e quali siano le prospettive future, dal momento che l’energia solare diventerà parte integrante di tutti i sistemi energetici sia su piccola che su grande scala. Sulla base di queste considerazioni si riportano i risultati prestazionali di alcuni casi di studio. Un primo studio ha riguardato l’analisi di un sistema solare a servizio di un edificio residenziale. La prima parte dello studio ha riguardato il monitoraggio in opera per circa un anno di tutte le grandezze utili ai fini della valutazione energetica. Successivamente è stato sviluppato un modello di simulazione dinamica del sistema edificio–impianto mediante il codice di calcolo dinamico TRNSYS. La seconda parte del lavoro prosegue con la trattazione di sistemi solari dedicati al raffrescamento estivo, conosciuti anche come sistemi di solar cooling. A tal riguardo, dopo una breve descrizione delle macchine frigorifere ad assorbimento, si riporta lo studio effettuato in collaborazione con un’azienda per lo sviluppo di un prototipo di macchina solare di tipo “Plug&Play”, basata su un brevetto depositato, da utilizzarsi nell’edilizia sia residenziale che del settore terziario. In particolare sono stati affrontati problemi di natura tecnica legati ad alcune limitazioni che il prototipo ha presentato e sono stati dimensionati i componenti principali del sistema. Nonostante in questa prima fase il lavoro sia stato di natura progettuale, è stato richiesto l’ausilio di simulazioni dinamiche per poter effettuare alcuni dimensionamenti e scelte. L’ultima parte di questo progetto è dedicata alla creazione di un modello dinamico complessivo del sistema considerando utenze di tipo sia residenziale che terziario. Mediante tale modello sono state effettuate delle simulazioni accoppiando la macchina a diverse tipologie di sistemi radianti. La parte conclusiva ha riguardato un altro caso di studio sul solar cooling, differente da quello precedente; tale lavoro ha avuto come primo obiettivo lo studio di una camera termica da installare all’interno di un’azienda al fine di testare i sistemi radianti di propria produzione. Successivamente si sono effettuate delle simulazioni analizzando una tipologia di sistema radiante a soffitto accoppiato ad un sistema di solar cooling. A differenza del lavoro precedente, in questo caso sono stati valutati i fabbisogni energetici legati al riscaldamento, al raffrescamento e alla produzione di acqua calda sanitaria per quattro zone climatiche.
10
SANTUNIONE, GIULIA. « Sviluppo di un metodo di invecchiamento biologico accelerato delle superfici ad alta efficienza energetica ». Doctoral thesis, Università degli studi di Modena e Reggio Emilia, 2022. http://hdl.handle.net/11380/1277157.
Texte intégralRésumé :
La crescita di biofilm sulle superfici esterne degli edifici è la causa del loro deterioramento estetico e funzionale. Gli organismi autotrofi quali alghe e cianobatteri sono i pionieri da cui può svilupparsi nel tempo una più complessa biocenosi comprensiva di batteri eterotrofi, funghi e licheni. La colonizzazione biologica dipende soprattutto dalle condizioni climatiche e microclimatiche che si verificano sulle superfici, quali la disponibilità di luce e acqua. Tale fenomeno, chiamato “bioageing”, è particolarmente impattante per le superfici ad alta efficienza energetica (cool materials) applicate agli edifici, caratterizzate da un’elevata riflettanza solare che limita il surriscaldamento, consentendo risparmi in energia di raffrescamento. I materiali cool rappresentano una delle più efficaci contromisure al fenomeno dell’Isola di Calore Urbano. Ad oggi, sono disponibili alcuni metodi standard per ottenere dati relativi all’invecchiamento naturale delle superfici (ASTM G7) e all’invecchiamento accelerato (ASTM D7897). Purtroppo però, quest’ultimo è focalizzato sullo studio del deterioramento chimico-fisico dei materiali, senza tenere in considerazione gli aspetti legati alla colonizzazione biologica.
Questo lavoro di ricerca ha come scopo quello di sviluppare un protocollo di prova ripetibile per accelerare la crescita di organismi su materiali cool, e determinarne il relativo calo in termini di riflettanza solare. La procedura sperimentale si prefigge di comprimere drasticamente i tempi di bioageing delle superfici, fenomeno che normalmente richiede alcuni anni per verificarsi in condizioni naturali. Il metodo è stato costruito studiando separatamente l’influenza dei parametri ambientali sulla ripetibilità del test. Sono state confrontate numerose condizioni sperimentali che sono poi state valutate per il livello di ripetibilità raggiunto. Lo strumento usato come camera di crescita è un bioreattore di tipo TIS (Temporary Immersion System). Tre tipologie di materiali cool sono state coinvolte: cool asphalt shingle (AS), single ply white membrane (WM) e white paint (WP). Ogni campione è stato caratterizzato dal punto di vista chimico e fisico sia prima che successivamente alla procedura di bioageing.
La crescita biologica è stata monitorata, misurata e correlata con i livelli di colonizzazione sulle superfici. Si è osservato che sia la crescita che la dinamica di colonizzazione ricalcano l’andamento dalla Legge di Avrami, ovvero un modello già utilizzato per simulare il processo di ricopertura algale nel tempo.
Altri aspetti del fenomeno di invecchiamento biologico sono stati studiati: è noto dalla letteratura che la deposizione di particolato e inquinanti sulle superfici (soiling) può rappresentare una fonte di nutrimento per gli organismi autotrofi. E’ stato inoltre osservato che l’esposizione a particolari sostanze inquinanti può inibire la crescita e diminuire la biodiversità delle comunità di organismi colonizzatori. È stato quindi confrontato il livello di invecchiamento biologico tra superfici nuove e precedentemente “soiled”. È stato infine valutata la risposta cellulare di alcune specie algali presenti nei contesti urbani allo stress abiotico rappresentato da una soluzione standard di inquinanti atmosferici.
Questa ricerca propone in definitiva un protocollo sperimentale di prova ripetibile per accelerare il processo di invecchiamento biologico delle superfici cool; la modularità e l’applicabilità del protocollo di prova nel definire la resistenza alla crescita biologica di una superficie vengono descritti dal modello di Avrami. Tra le prospettive future della ricerca vi è la validazione del protocollo studiato su altre tipologie di materiali, oltre a quella di verificare la riproducibilità del metodo in altri laboratori.Biological growth on building surfaces can be responsible of degradation of their aesthetical and functional properties. Phototrophic organisms as algae and cyanobacteria have been identified as the first ones to colonize surfaces and allow the formation of following biocenosis, where also heterotrophic bacteria and fungi are involved. Biological colonization depends mainly on climate and microclimate conditions over and all around surfaces, mainly moisture and light availability. This phenomenon is particularly damaging for solar reflective materials (cool building materials), which are characterized by the ability to reflect solar radiation in the whole wavelength spectrum and remain cooler under the sun. Cool materials represent one of the most efficient countermeasures to the urban heat island effect, which causes temperatures in urban areas to be significantly higher than in the surrounding rural areas. Several standards are nowadays available to investigate natural ageing of cool materials (ASTM G7) and accelerated ageing (ASTM D7897). Unfortunately, these standards are mostly focused onto surface soiling and they do not take into proper account the presence and growth of microorganisms. This research work was firstly aimed to develop a laboratory procedure able to reproduce biological colonization on new materials in a repeatable way, in order to quantify the loss of energy performance due to the biological growth. Another goal was to reduce the bio ageing test duration, which normally requires many years through natural exposition. The novel method was built step by step studying separately the influence of different experimental parameters on biological growth then on repeatability of the test. Several setups and environmental conditions have been tested, compared and finally evaluated according to repeatability of results. The experimental device used to expose material samples to bioageing was a bioreactor -a Temporary Immersion System (TIS); three different types of high-efficiency building materials samples, precisely white asphalt shingle (AS), single ply white membrane (WM) and white paint (WP) were tested. Materials samples have been characterized in terms of physical and chemical properties, before and after bioageing exposure. Furthermore, biological growth has been monitored, measured, and finally correlated to colonization level on surfaces. Algae and cyanobacteria growth as well as bio-colonization dynamics describes a curve which follow Avrami’s law, a model previously used to simulate algal colonization process as temporal evolution. Ancillary aspects to bioageing phenomenon were investigated in this research: scientific literature reports that the deposition of soiling on surfaces seems to provide a nutrient layer for phototrophic organisms, encouraging their growth; however, it has been also observed that the presence of atmospheric pollutants could inhibit both the size and diversity of the microbial community. Hence, algal and cyanobacteria growth on soiled surfaces was here studied and compared to growth on new ones. Moreover, metabolites profile production of some algal species after their exposure to soiling mixture was described, in order to outline the influence and effects of soiling solution as abiotic stress to algal cells metabolism. Definitely, this research offers an experimental protocol to induce accelerate bio ageing process on cool building surfaces, providing data about repeatability and strength of the method; the modularity and the application of the protocol to define bio-resistance of a surface type was finally described by Avrami’s model. The application of the protocol on different types of cool surfaces and reproducibility definition are expected as future perspectives.
Livres sur le sujet "FISICA SOLARE"
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Degl’Innocenti, Egidio Landi. Fisica solare. Milano : Springer Milan, 2008. http://dx.doi.org/10.1007/978-88-470-0678-2.
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Solar radiation resource assessment project : Program overview of fiscal year 1993. Golden, CO : National Renewable Energy Laboratory, 1994.
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David, Atkinson, et Jet Propulsion Laboratory (U.S.), dir. Spacecraft Health Automated Reasoning Prototype (SHARP) : The fiscal year 1989 "SHARP portability evaluations" task for NASA Solar System Exploration Division's Voyager Project. Pasadena, Calif : National Aeronautics and Space Administration, Jet Propulsion Laboratory, California Institute of Technology, 1990.
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Seitz, Frederick. The modern theory of solids. New York : Dover Publications, 1987.
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United States. Congress. Senate. Committee on Energy and Natural Resources. Proposed fiscal year 1995 budget request for Department of Energy (renewable energy programs) : Hearing before the Committee on Energy and Natural Resources, United States Senate, One Hundred Third Congress, second session ... March 8, 1994. Washington : U.S. G.P.O., 1994.
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Office, General Accounting. Tax administration : IRS' abatement of assessments in fiscal years 1995-98 : report to the Joint Committee on Taxation. Washington, D.C : The Office, 1999.
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Office, General Accounting. Tax administration : IRS' abatement of assessments in fiscal years 1995-98 : report to the Joint Committee on Taxation. Washington, D.C. (P.O. Box 37050, Washington 20013) : The Office, 1999.
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Office, General Accounting. Tax administration : Results of IRS' mid-fiscal year 1989 financial review : report to the Chairman, Subcommittee on Oversight, Committee on Ways and Means, House of Representatives. Washington, D.C : The Office, 1989.
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Office, General Accounting. Tax administration : Assessment of IRS' report on its fiscal year 1995 compliance initiatives : report to the Ranking Minority Member, Committee on Governmental Affairs, U.S. Senate. Washington, D.C : The Office, 1997.
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Fisica Solare (UNITEXT / Collana di Fisica e Astronomia). Springer, 2007.
Trouver le texte intégralChapitres de livres sur le sujet "FISICA SOLARE"
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Chami, Ralph, Thomas F. Cosimano, Raphael Espinoza et Peter Montiel. « The Challenge of Macroeconomic Stabilization in Fragile States ». Dans Macroeconomic Policy in Fragile States, 209–34. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780198853091.003.0008.
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We develop a dependent-economy model with macroeconomic policies derived from a policymaker maximization problem. The model assumes that the probability of state failure is a function of the economic situation and the government’s capacity to deliver favors through public employment. We solve the model under three different policymakers’ objectives: the “political” policymaker, technocratic policymaker, and social planner. Public employment is higher if it is decided by the political policymaker, but the probability of state failure is higher because fiscal deficits lead to inflation. A technocratic policymaker implements a conservative fiscal plan but the probability of state failure is higher than what could be achieved if this probability was taken into account in the objective function. Comparative statics provide a “test” of the objective function: a benevolent policymaker should take advantage of additional fiscal space to improve the economy, not to spend all resources on policymaker consumption or on public wages.
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Frizell, Jakob. « War and Modern Taxation ». Dans Global Taxation, 43–66. Oxford University Press, 2022. http://dx.doi.org/10.1093/oso/9780192897572.003.0002.
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The chapter analyses the effect of war on tax modernization across world regions. By the example of the Angolan civil war, it questions the conventional wisdom according to which warfare is a distinctly European pathway to fiscal development. It argues that the fiscal exigencies of war are near-universal and lead to similar tax policy reactions irrespective of geographical area. This is equally true for civil as for interstate wars. The availability of natural resource rents or external finance may mitigate the immediate effect of war, but does not neutralize it. The argument is supported by a series of logit regressions estimating the effect of war on the probability of permanently introducing any of six modern taxes in a global sample of countries covering the two last centuries. The sole diverging case is Latin America, where the link between war and taxation is weak at best. Latin America thus represents the exception from the ‘bellicist’ rule of fiscal development.
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Timilsina, Govinda. « The Economics of Renewable Energy Promotion Policies ». Dans Practice, Progress, and Proficiency in Sustainability, 270–84. IGI Global, 2016. http://dx.doi.org/10.4018/978-1-5225-0440-5.ch012.
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Large-scale deployment of renewable energy technologies, such as wind power and solar energy, has been taking place in industrialized and developing economics mainly because of various fiscal and regulatory policies. An understanding of the economy-wide impacts of those policies is an important part of an overall analysis of them. Using a perfect foresight computable general equilibrium model, this study analyzes the economy-wide costs of achieving a 10 percent share of wind power in Brazil's electricity supply mix by 2030. The study finds that the expansion of wind power would increase GDP in Brazil. The study also finds that a production subsidy financed through increased value-added tax would be superior to a consumption mandate where electricity utilities are allowed to pass the increased electricity supply costs directly to consumers. These two policies would impact various production sectors differently to achieve the wind power expansion targets.
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Akar, Sevda, et Dilek Akbaş Akdoğan. « Environmental and Economic Impacts of Wave Energy ». Dans Practice, Progress, and Proficiency in Sustainability, 285–309. IGI Global, 2016. http://dx.doi.org/10.4018/978-1-5225-0440-5.ch013.
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The wave energy is one of the most important renewable energy sources and it has many advantages compared to other renewable energies. First, it is more reliable. Second, the cost of wave energy is competitive with other sources when it is used as a primary power source. Third, its energy density and deployment potential are higher than the wind and solar energy. Fourth, the wave energy has minor negative environmental impacts and production amount of the wave energy is more predictable. In the study, the applications of wave energy production are discussed in European Union countries in which have started to operate wave energy, recently. It is also tried to evaluate the feasibility of wave energy production opportunities in Turkey. As a result of the study, it can be said that the Black Sea has the highest wave energy potential in Turkey. Industrial production of wave energy actualized by fiscal incentives and this may lead to many social benefits such as increasing employment, reducing external dependency and diminishing greenhouse gases emission.
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Bomtempo, Eugênio Pacceli de Morais. « Urbanization of Slums and the Taxation of Heritage in the Brazilian Municipal Scope ». Dans METHODOLOGY FOCUSED ON THE AREA OF INTERDISCIPLINARITY- V1. Seven Editora, 2023. http://dx.doi.org/10.56238/methofocusinterv1-006.
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The situation of cities in Brazil has worsened in such a way that it compromises all the rights recognized by the Democratic Rule of Law. Municipalities do not have enough tax revenue to eradicate slums and urbanize the cities, which are hostage to organized crime and increasing violence. Through the qualitative method, the purpose of this study is to investigate the challenges encountered in taxing the heritage so that there are resources to solve the historical problems of the slums. It was concluded: it is possible to increase the tax collection on assets, but the challenges are persistent. They require new techniques and correct measures. The citizen must be converted into a development partner. Failure to tax properly violates Article 11 of the Fiscal Responsibility Law and can generate accountability. This research lacks the necessary depth to exhaust such complex relationships, but it can mean an invitation to luminaries to dedicate themselves to the theme.
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Pachpande, Priti, et Sham Bachhav. « One Nation One Tax ». Dans Indian Business Case Studies Volume IV, 47—C7.P37. Oxford University PressOxford, 2022. http://dx.doi.org/10.1093/oso/9780192869401.003.0007.
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Abstract The Impact and Relevance of the GST (One tax) Bill Goods and Services Tax will be instrumental in helping the GDP of India to grow by 2%. The GST also offers a solution to the multinationals as it breaks down the indirect tax structure into one single tax payable by the companies. Although the states have feared loss of fiscal powers, the Constitutional amendment bill has promised to solve this by giving compensation packages for three years for any kind of revenue loss. The bill has proposed to have GST council wherein all union and state ministers in charge of finance will be on an equal footing. It will also have a dispute settlement authority to mitigate the tensions between the centre and state smoothly. One main contention for the state in the GST is the inclusion of petroleum products. The current consensus on this is that the states will continue to levy sales tax/VAT on these with the exception of imports and inter-state trade. The main function of the GST is to transform India into a uniform market by breaking the current fiscal barrier between states. Thus the GST will facilitate a uniform tax levied on goods and services across the country. Currently, the indirect tax system in India is complicated with overlapping taxes levied by the Centre and the State separately. Framework of the GST will replace indirect taxes. The GST will have a ‘dual’ structure, which means it will have two components—the Central GST and the State GST. They will both have separate powers to legislate and administer their respective taxes. Thus equally empowering both. Taxes such as excise duty, service, central sales tax, VAT (value added tax), entry tax, or octroi will all be subsumed by the GST under a single umbrella. With passing of the GST bill, we can expect a climate of improved tax compliance. Thus, the GST will basically have only three kinds of taxes, Central, State, and another called the integrated GST to tackle inter-state transactions.
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Feinman, Gary M., et Linda M. Nicholas. « Re-envisioning Prehispanic Mesoamerican Economies ». Dans Modes of Production and Archaeology. University Press of Florida, 2017. http://dx.doi.org/10.5744/florida/9780813054308.003.0011.
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Exuberant Spanish accounts of the 16th century Aztec market system have been part of the documentary record for hundreds of years. Yet the significance of markets and marketplace exchanges in the prehispanic Mesoamerican world has consistently been under-theorized until relatively recently. One of the key, but not sole, factors that has forced a shift in our analytical framing is the archaeological evidence that almost all production (craft and agrarian) was situated domestically in prehispanic Mesoamerica, yet many households were producing at least in part for exchange. In consequence, centralized managerial control over production would have been difficult if not impossible to sustain. Although such findings have cast great doubt on long-held visions of Mesoamerican command economies, understanding how power was funded in different prehispanic time/space contexts remains a central issue with a greater analytical focus now shifted to the fiscal foundations of collective action, governance, and power. Despite important shifts in the specific lessons and legacies that we draw from Marx’s historical analysis, intellectual parallels and debts to this materialist frame of thought remain, and these help generate new questions to guide the way forward for studying this region’s past.
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Weimer, David L. « Policy analysis in the United States ». Dans Policy Analysis in the United States. Policy Press, 2018. http://dx.doi.org/10.1332/policypress/9781447333821.003.0002.
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Four demands have driven the development of policy analysis in the U.S. First, reformers have sought evidence to support their efforts. Beginning with the municipal bureaus of the Progressive Era, advocacy groups have sought supportive policy analysis, resulting in the proliferation of ideologically differentiated think tanks that produce policy research. Second, politicians have recognized the need for specialized expertise to address pressing problems. Operations research grew out of efforts to solve problems facing the U.S. in World War II and led to subsequent efforts to improve bureaucratic decision-making capacity. Third, the growing scope and complexity of government have led to a demand for information to support routine decision processes. Fiscal offices support state budgeting and the Congressional Budget Office, Government Accountability Office, and Congressional Research Service support the routine business of Congress. Fourth, politicians have sought to discipline their own (and especially others’) future actions by mandating that analyses be applied to certain classes of decisions. Legislative requirements that the Army Corps of Engineers consider the benefits of investment projects were introduced at the beginning of the last century, legislative requirements for the completion of environmental impact statements were imposed in 1970, and beginning in 1981, executive orders have required cost-benefit analyses be completed for major agency rulemakings. Higher education has responded to these demands by supplying persons trained specifically in policy analysis.
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Geda, Alemayehu, Fredrik Huizinga et Addis Yimer. « Exogenous Shocks and Macroeconomic Policy Analysis using Applied Macro-Econometric Models in Africa ». Dans Economic Modeling, Analysis, and Policy for Sustainability, 74–129. IGI Global, 2016. http://dx.doi.org/10.4018/978-1-5225-0094-0.ch006.
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In this study we have developed a macro-econometric model for a typical supply constrained African economy. This is aimed at developing a theoretical and empirical template for such policy tools which are increasingly demanded in Africa. We have concretized it by building a macro-econometric model for Rwanda. The Rwanda macro-econometric model has 107 equations of which 72 are endogenous. In addition, a supplementary ARIMA based model with 33 equations for exogenous variable is built to make the model useful for forecasting. The fiscal, balance of payment and money supply block of the model is fairly disaggregated to offer an adequate picture of the macro economy. An econometric estimation of the core behavioral equations of the model using equilibrium [error]-correction approach is made with the database that stretches from 1960 to 2009. The model is similar to successful macro models in the region such as that of the KIPPRA-Treasury model of Kenya. It can also easily be further extended to the support budgeting, forecasting and macroeconomic policy analysis work at the relevant ministries in Africa such as the Ministry of Finance in Rwanda. We have managed to successfully solve the model from 1999 to 2009 and forecast major macro outcomes from 2010 to 2014. We have also used it to conduct a policy simulation exercise which is very important for policy makers such as those in Rwanda. We hope this model offers a theoretical and empirical framework for building macro model across Africa which is increasingly being demanded in many countries.
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Shettigar, Jagadish, et Pooja Misra. « Giving Back to Society ». Dans Resurgent India, 160—C3.2.P14. Oxford University PressOxford, 2022. http://dx.doi.org/10.1093/oso/9780192866486.003.0032.
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Abstract The grim picture painted by GDP numbers during the Covid-19 outbreak had begun ringing alarm bells for policy-makers and the Government machinery alike. There was an outcry by economists for a stimulus package along the lines provided by Governments of advanced economies running into trillions of dollars. While the Government of India ably responded to the need of the hour and provided a stimulus package to the tune of Rs. 20 lakh crores (equivalent to 10% of GDP), many deliberations post this announcement were pointing towards the fact that the stimulus was inadequate for reviving the Indian economy, and the Government must pull out all stops to get the economy back on track. The point that was being missed out here and what the chapter delves into was that the hands of the Government were tied due to the availability of limited fiscal space. The question that all of us need to answer is: In times of an unprecedented situation such as a health pandemic, is it the whole sole responsibility of the Government alone to step forward and take action in such difficult times OR should Corporates and citizens join hands with the Government and work towards nation building especially during a crisis in hand? Should not the wealthy and citizens with deep pockets rise to the occasion and be a partner in the Government’s efforts in bringing back the situation to normalcy? Given the health emergency and crisis situation, cash- rich corporates and wealthy individuals with deep pockets should co- create their CSR and philanthropic strategies as an effective response to the virus outbreak.
Actes de conférences sur le sujet "FISICA SOLARE"
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Hayakawa, Yuta, Hiroto Hamane et Akihiko Nakamura. « Reverse and Same Phase Hydraulic 4WS System for Solar Vehicle ». Dans FISITA World Congress 2021. FISITA, 2021. http://dx.doi.org/10.46720/f2020-vdc-083.
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"This paper introduces hydraulic 4WS system developed for the solar vehicles that participated in the 2017 and 2019 Bridgestone World Solar Challenges. This is the world's first solar powered vehicle to demonstrate hydraulic 4WS. The reverse phase 4WS allows the layout of steered tires are in a limited vehicle body space. Furthermore, in order to convert the crosswind into propulsion when the vehicle receives a crosswind, same phase 4WS was developed. The 2017 vehicle introduced a hydraulic 4WS system with multi-link and rigid suspension. In 2019 vehicles, 4WS was introduced to the trailing arm suspension. The same phase steering angle can be controlled from the driver's seat. The hydraulic circuit uses three cylinders. There is a cylinder mounted on the front steering mechanism, a cylinder that steers the rear wheels, and a centering cylinder that is responsible for adjusting and restoring the center position in the middle. When a load is input to the front cylinder, the centering cylinder and the rear cylinder operate. The steering unit consists of a rack and pinion gear that changes the steering wheel into linear motion, a front cylinder and a stopper which starts the operation of the 4WS. Normally, only the front wheels are steered by rack and pinion gears. When the steering is turned beyond a certain turning angle, the 4WS is driven for the first time by the stopper. The centering cylinder is loaded with an initial load by a spring. When the load on the front cylinder is stopped, all cylinders return to the initial position. In addition, the centering cylinder mechanism was designed so that the set length of the spring could be adjusted. The initial positions of the three cylinders can be adjusted by adjusting the spring set length. That is, same phase 4WS can be realized by this adjustment. This papers that hydraulic 4WS can be introduced for two different suspensions. The proposed systems were successfully tested on 3000 km of public roads in Australia. This paper introduces Reverse and Same Phase Hydraulic 4WS system."
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TSIMIS, CHARALAMPOS, et Xavier Montane. « Numerical and physical experiments on the passby noise of the iShare ». Dans FISITA World Congress 2021. FISITA, 2021. http://dx.doi.org/10.46720/f2020-mcf-005.
Texte intégralRésumé :
"This paper presents the work of an R&D project which aims to augment IDIADA’s capabilities in the prediction of aerodynamically generated passby noise via CFD simulations. The project focuses on the noise generated by the A-pillar and the side view mirror of IDIADA’s iShare concept car and combines numerical and experimental investigations. The objective is to develop and validate the numerical aeroacoustics methodology, as well as to develop an experimental methodology that makes use of IDIADA’s semi-anechoic chamber. The main numerical methodology used was based on the surface integral formulation of Ffowcs Williams-Hawkings, this is an acoustic analogy which splits up the problem to the local noise generation first and to the propagation of the acoustic wave second. For the local noise generation two approaches were used, a compressible and an incompressible one. The latter assumes that the acoustic field has a negligible effect on the hydrodynamic flow field, which simplifies the physics involved. The technique uses the theory of Acoustic Perturbation Equations to model the acoustic field that is generated by the flow of an incompressible fluid. The solver used was STAR-CCM+. Parallel to the numerical methodology development the project developed an experimental methodology. This involved the design of a nozzle that could channel the available flow of the semi-anechoic chamber into a high velocity jet that could be directed towards the A-pillar or the side view mirror of a vehicle, thus focusing the noise generation in these features. Finally, the numerical tests were compared to the experiments for validation. The paper will present the numerical and experimental SPL measurements in an array of microphones placed 0.6m away from the left hand side of the iShare, as well as, CFD visualisations of the flow field generated and of the noise sources. The numerical results follow the trends of the experimental results, but for certain frequency octaves there was a small deviation in the predicted SPL. Overall the agreement was satisfactory. This work has shown the potential of the methodologies used to solve aeroacoustics problems and the limitations of what can be tested in IDIADA’s semi-anechoic chamber and of the numerical methods. The paper will elaborate in detail on these findings. This is a new field for IDIADA, and it offers a new aeroacoustic validation case for numerical codes to be compared against."
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Sileghem, Louis. « A New Engine Concept to Control the Ignition Timing of HCCI Combustion : Piston Assisted Compression Ignition (PACI) ». Dans FISITA World Congress 2021. FISITA, 2021. http://dx.doi.org/10.46720/f2020-adm-073.
Texte intégralRésumé :
HCCI engines have long been seen as the holy grail of internal combustion engines. These engines would combine a very high efficiency with ultra-low emissions. The bottleneck of HCCI engines is the lack of control over the ignition timing of the homogeneous air-fuel mixture. In this paper, a new engine concept is presented to solve this problem. In this new concept, next to the main compression of the engine, a secondary piston is provided in the combustion chamber to give an additional compression for a short duration close to the top dead center of the main piston. As a result, this new internal combustion engine concept is called "Piston Assisted Compression Ignition" or "PACI". This secondary piston provides the additional compression that is needed to ignite the air-fuel mixture at the right timing during the engine cycle for a range of different loads and different inlet temperatures. In the same way as the combustion is initiated by a spark in a spark ignition engine, this concept tries to initiate and control the combustion in a compression ignition engine by an additional mechanical compression near the top dead center. First, insights are given about the possibilities of this new engine concept and secondly, calculations of the ignition timings for a load range at different inlet temperatures are presented. The ignition timings are compared with the ignition timings that would be possible without the secondary piston. Calculations with methanol (single-stage autoignition) and PRF95 (two-stage autoignition) have shown the potential of this concept to better control the autoignition timings for a load and temperature range for both these fuels compared to the usual HCCI concept with a single compression stroke. To conclude, this research shows the potential of a radical new engine concept that could be an interesting way to solve the control problem of HCCI engines if possible mechanical challenges of this concept can be overcome.
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Ianni, A. « Solar Neutrinos : Present and Future ». Dans IFAE 2005 : XVII Incontri de Fisica delle Alte Energie ; 17th Italian Meeting on High Energy Physics. AIP, 2005. http://dx.doi.org/10.1063/1.2125655.
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Griffin, Steven T., et Thomas E. Wyatt. « Solar panel sensor modeling and fiscal modeling ». Dans 2014 IEEE Sensors Applications Symposium (SAS). IEEE, 2014. http://dx.doi.org/10.1109/sas.2014.6798912.
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Shah, Sameer Rafiq, Dilip Kumar et Nishant Tiwari. « Design and Development Of An In-Wheel Suspension With Novel Automatic Camber Control Strategy For Improved Handling ». Dans FISITA World Congress 2021. FISITA, 2021. http://dx.doi.org/10.46720/f2020-vdc-081.
Texte intégralRésumé :
In this era of electrification, HEVs are mainly focused on weight and space saving. This is done to ensure the maximum size of the battery package on the vehicle. This situation demands for a drive by wire systems which makes the vehicle lighter as well as more spacious. This paper introduces a new type of In-Wheel suspension has been introduced in this paper. The problem of large suspension systems and its bulkiness were studied. Vehicle instability while driving and cornering was also stated. And the suspension's capability to handle uneven tyre wear which is caused due to improper or fixed camber angle was also addressed. The Novel In-Wheel Suspension is introduced in this paper which houses all the crucial parts of the suspension inside the rim of the wheel thus making it compact, lighter and sturdy. Parts were first designed by the principles of Machine Design, Kinematics and Mechanics of Materials. They were later modelled on Solid Edge ST7. Structural simulations was carried out on FEA Solver under highly strained conditions and also under dynamic loading and the results were satisfactory. A scaled prototype was made by manufacturing the parts on CNC machine. Later the suspension was assembled by brazing the parts together. The Impulse hammer technique was used to carry out the modal analysis which was used to study the damping characteristics of the suspension. Another innovation is introduced in this suspension which the Novel concept of Automatic Camber Control strategy which calibrates the camber angle of the wheel in real-time and greatly improves the performance as well as stability of the vehicle. The design process involved understanding the scaling down the size of the suspension without compensating the functionality of the suspension. The working prototype of the suspension was constructed and after rigorous testing which were carried out. It was found that the performance of suspension under low traction conditions was enhanced.
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Mindl, Pavel, Zdeněk Čeřovský et Pavel Mňuk. « Optimization of induction machine generator regime in electro mobile ». Dans FISITA World Congress 2021. FISITA, 2021. http://dx.doi.org/10.46720/f2020-adm-099.
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The main physical parameters in case of traction vehicle design are: Maximal desired velocity, desired traction power and traction torque on vehicle velocity dependence. In case of electrically driven vehicles these requirements are solved by the variable parameters of electric energy for motor supply. Power required for motor terminals in accordance with vehicle speed are for comparable vehicles the same. In case of electric drive, the power, needed for motor supplying could have different parameters, characterized by the supply voltage, current and its frequency. Supply voltage and current frequency must be proportional to vehicle required speed of course. But torque creation is very sensitive on air gap magnetic field revolutions and machine rotor revolutions difference. This difference is characterized by the rotor current frequency (f2) or by the corresponding rotor current angular velocity ω2 = 2π f2. Operational regime of AC induction motor is characterized by three independent parameters: Stator voltage U1, stator voltage frequency f1 and rotor current frequency f2. These parameters determinates torque T, stator current I1 and its relation T/I1 unequivocally. Electrically driven vehicles enable to recuperate electric energy during braking interval. It is very temptingly to recuperate braking energy with maximal efficiency when relation I/T achieved its maximum for desired braking torque. To solve this problem is possible theoretically in case, if basic motor parameters – winding inductance and resistivity are constant parameters. But in real case resistivity changes with temperature and inductance depends on current. Therefore, in real case of this troubleshooting is based on theory and experiments combination. In case of induction machine working regime optimization it is necessary to split the task on the motor and generator regimes. In case of electric vehicle recuperation braking, it is convenient to achieve for desired braking torque maximal active current for electric accumulator charging. From theory and previous experiments imply that it exists I/T relation maximum like in motor so in generator regimes. Optimization of motor regime were analysed and experimentally verified in L/1/. The case of recuperation regime is analysed in this article.
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Li, Congcong, Lijun Zhang et Dejian Meng. « A Two-stage Ground Segmentation and Multi-frame Point Clouds Based Road Boundary Extraction Algorithm ». Dans FISITA World Congress 2021. FISITA, 2021. http://dx.doi.org/10.46720/f2021-dgt-043.
Texte intégralRésumé :
Lidar based perceptual system is an important aspect of autonomous driving. In this paper we focus on ground segmentation and road boundary extraction in point cloud. In order to solve the problem that most of the current ground segmentation algorithms can not make full use of the data information, which leads to poor segmentation results on complex roads (such as slopes and undulating roads), this paper presents a two-stage ground segmentation algorithm that combines the Cloth Simulation Filtering (CSF) algorithm and the 2.5D grid map method. In the first stage, CSF is applied to filter out most ground points. Then we project the non-ground points obtained in the first stage to a grid map and judge the attribute of each grid in the map for further segmentation refinement. After ground segmentation, road boundary extraction also plays an indispensable role to obtain drivable area and reduce search space. However, most of road boundary extraction methods focus on single frame data and discard useful historical information. In this paper, the road boundary seed points of the current frame are accumulated from previous multiframe point clouds. After that, the curbs are fitted via the parabola model and RANSAC algorithm. Extensive simulations in Prescan show that the proposed ground segmentation algorithm can adapt to various complex road conditions. Field tests were also conducted to demonstrate the effectiveness of the proposed segmentation method. Our experimental results of road boundary extraction also show that after multiframe accumulation, more detailed information of road boundary can be obtained, resulting in more accurate detection results. In straight part the extraction accuracy of road boundary is more than 96%; in the curve part, the extraction accuracy of road boundary is not as stable as the straight part, but the lowest extraction accuracy is 89.33%, and the average extraction accuracy is 95.64%. Finally, we analyze the influence of localization and attitude angle error on road boundary extraction.
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Grober, Florian, Andreas Janßen et Ferit Küçükay. « Customer-Focussed Automatic Test Course Design ». Dans FISITA World Congress 2021. FISITA, 2021. http://dx.doi.org/10.46720/f2020-dgt-007.
Texte intégralRésumé :
Customer centricity gains increasing importance in vehicle development. With respect to durability testing and approval of prototypes, it causes the requirement for testing procedures which highly comply with the occurring loads during customer operation. In this manner, lightweight construction is enabled and considerable economic advantages are raised by avoiding oversizing as well as undersizing of components. As current state of the art, vehicle manufacturers use special test courses on proving grounds or public roads which must be endured damage-free by the vehicle prototype until a compulsory mileage is reached. Alternatively, the course's loads can be reproduced on a test rig to reduce the required test time. The definition of these test courses is based on long-standing experiences. According to new trends in the automotive sector, as for example electrification and shared mobility, it can be predicted that the customer loads will change in accelerating cycles. Correspondingly, these previous experiences cannot be used offhandedly for such new questions and existing test courses become invalid. To solve the described problem of inflexibility, this article presents a technology for automatic generation of appropriate test courses from customer field data. The developed algorithm transforms customer-oriented load spectra into a test course that reproduces the occurred loads as good as possible. For this purpose, digital map data is combined with measured track load data and consecutive road segments are assembled to a complete test course by heuristic methods. This resulting course requires a minimum driving distance and induces approximately the same loads as the destination load spectra derived from customer field data. The optimisation can be processed simultaneously for several different load channels. Via using automation and heuristics, a good performance arises and enables a fast as well as flexible generation of tailored test courses pursuant to current demands. In contrast to the inflexible test course concept used so far, the described technique represents a good improvement of customer-oriented testing methodology. Therefore, it provides a great novelty value. In the article, the process of an automatic test course design is demonstrated and validated by means of a real example, which shows the practical applicability. The latter is also proved by the fact that the described method has already been used successfully in the research and development of Volkswagen AG.
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Erwin Brosch, Erwin Brosch, et Daniel Trost Daniel Trost. « Validation of a Data-Based Thermal Model of a Gearbox ». Dans FISITA World Congress 2021. FISITA, 2021. http://dx.doi.org/10.46720/f2021-adm-154.
Texte intégralRésumé :
"Oil sump temperature in conventional gearboxes is one of the most important technical framework conditions in terms of research, development and especially in testing of gearboxes. Nevertheless, it is not always possible to set a suitable sensor or to access sensor data with sufficient quality. The need for a simulated oil sump temperature is, among others, for such purposes. In a previous work, an approach for this is presented. A thermal model of a gearbox is generally created on the basis of lumped-element models. Therefore, the thermal masses, such as oil, gears and the gearbox housing, are modeled as lumped-capacitance and the thermal transitions between them as thermal resistances. In addition, there are thermal sources due to heat generation and thermal sinks due to cooling. In principle, a high level of detailed knowledge would be required to parameterize this lumped-element model. To circumvent this, a data-based approach for parameter identification is chosen. For this purpose, an optimization problem is formulated which aims at minimizing the error between simulated and measured values. The methods of genetic algorithms are used to solve the optimization problem. This computationally expensive step is done in advance, apart from the actual use of the model. Thus, a model with little detailed knowledge and without extensive model building can be generated. The preliminary conceptual paper focusses on gearboxes of battery electric vehicle (BEV) with low thermal masses. In contrast, transmissions in conventional and in hybrid electric vehicles (HEV) are steadily increasing in size, number of gears, and thermal mass. The generality of the approach described above is shown by modeling a very large gearbox in the present work. For the specific case, even a gearbox with a coolant/oil heat exchanger is considered. Beside this extension of the model, the former approach has additionally been improved regarding the accuracy of the results. By varying the measured and simulated model inputs, the parameters can be determined more accurately. Furthermore, the final simulation model is upgraded with these additional model inputs as well, which leads to a significant improvement of the simulation results. The model complexity even decreases. These results base on a large measurement data set, which is necessary for the identification of the parameters. In addition, measurement data is needed for the validation of the method. An extensive series of measurements have been taken on an electric powertrain test bench and is presented within this work. Both, generic measurement runs, which are ideal for system identification, and runs similar to a real driving data were recorded."
Rapports d'organisations sur le sujet "FISICA SOLARE"
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Author, Not Given. Solar thermal program summary : Volume 1, Overview, fiscal year 1988. Office of Scientific and Technical Information (OSTI), février 1989. http://dx.doi.org/10.2172/10102066.
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Author, Not Given. Solar buildings program summary : Volume 2 : Research summaries, fiscal year 1988. Office of Scientific and Technical Information (OSTI), avril 1989. http://dx.doi.org/10.2172/6053553.
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Author, Not Given. Solar Radiation Resource Assessment Project. Program overview of fiscal year 1993. Office of Scientific and Technical Information (OSTI), juin 1994. http://dx.doi.org/10.2172/10177326.
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Sengupta, Manajit, Aron Habte, Yu Xie, Peter Gotseff, Mark Kutchenreiter, Afshin Andreas, Ibrahim Reda et al. Solar Radiation Research Laboratory (SRRL) Final Report : Fiscal Years 2019-2021. Office of Scientific and Technical Information (OSTI), février 2022. http://dx.doi.org/10.2172/1846616.
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Riordan, C., E. Maxwell, T. Stoffel, M. Rymes et S. Wilcox. SERI Solar Radiation Resource Assessment Project : Fiscal Year 1990 Annual Progress Report. Office of Scientific and Technical Information (OSTI), juillet 1991. http://dx.doi.org/10.2172/5425544.
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Sengupta, Manajit, Yu Xie, Aron Habte, Grant Buster, Galen Maclaurin, Paul Edwards, Haiku Sky, Mike Bannister et Evan Rosenlieb. The National Solar Radiation Database (NSRDB) Final Report : Fiscal Years 2019-2021. Office of Scientific and Technical Information (OSTI), février 2022. http://dx.doi.org/10.2172/1847083.
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Méndez-Vizcaíno, Juan C., et Nicolás Moreno-Arias. A Global Shock with Idiosyncratic Pains : State-Dependent Debt Limits for LATAM during the COVID-19 pandemic. Banco de la República, octobre 2021. http://dx.doi.org/10.32468/be.1175.
Texte intégralRésumé :
Fiscal sustainability in five of the largest Latin American economies is examined before and after the COVID-19 pandemic. For this purpose, the DSGE model in Bi(2012) and Hürtgen (2020) is used to estimate the Fiscal Limits and Fiscal Spaces for Peru, Chile, Mexico, Colombia, and Brazil. These estimates advance the empirical literature for Latin America on fiscal sustainability by offering new calculations stemming from a structural framework with alluring novel features: government default on the intensive margin; dynamic Laffer curves; utility-based stochastic discount factor; and a Markov-Switching process for public transfers with an explosive regime. The most notable additions to the existing literature for Latin America are the estimations of entire distributions of public debt limits for various default probabilities and that said limits critically hinge on both current and future states. Results obtained indicate notorious contractions of Fiscal Spaces among all countries during the pandemic, but the sizes of these were very heterogeneous. Countries that in 2019 had positive spaces and got closer to negative spaces in 2020, have since seen deterioration of their sovereign debt ratings or outlooks. Colombia was the only country to lose its positive Fiscal Space and investment grade, thereby joining Brazil, the previously sole member of both groups
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Menicucci, D. The Solar Thermal Design Assistance Center report of its activities and accomplishments in Fiscal Year 1993. Office of Scientific and Technical Information (OSTI), mars 1994. http://dx.doi.org/10.2172/10138122.
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Menicucci, David. The Solar Thermal Design Assistance Center : Report of Its Activities and Accomplishments in Fiscal Year 1992. Office of Scientific and Technical Information (OSTI), janvier 1993. http://dx.doi.org/10.2172/1545835.
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Pérez Urdialez, Maria, Ariel Yépez, Mauricio Tolmasquim, Claudio Alatorre, Alejandro Rasteletti, Marco Stampini et Michelle Hallack. El papel de la transición energética en la recuperación sostenible de América Latina y el Caribe. Inter-American Development Bank, avril 2021. http://dx.doi.org/10.18235/0003214.
Texte intégralRésumé :
Muchos países de América Latina y el Caribe (ALC) y del mundo se encuentran actualmente desarrollando ambiciosos planes para la reactivación económica y la generación de empleo en el período pospandemia. Estos planes representan una oportunidad única para la inclusión de medidas que, al mismo tiempo que reactivan la economía, también apoyan la transición energética de los países de la región. Esta nota técnica busca apoyar a los países de la región en el diseño de planes de recuperación sostenibles, presentando consideraciones que deben ser tomadas en cuenta para el diseño e implementación exitosa de estos planes. Los países de ALC presentan importantes ventajas comparativas para la transición hacia matrices más sostenibles. Particularmente, se destacan la gran cantidad de recursos naturales para la producción de biomasa, energía eólica y solar. Adicionalmente, las subastas para la adjudicación de nueva capacidad energética son habituales en la regionales y tanto desarrolladores internacionales de energías renovables como prestamistas internacionales presentan interés en el financiamiento de dichas inversiones. Es por ello que los países latinoamericanos y del Caribe tienen una oportunidad única para llevar adelante una transición energética sostenible que además incremente los recursos disponibles para dicho fin. Las inversiones sostenibles para fomentar la transición energética deben ser acompañadas de medidas que amplíen el espacio fiscal de los gobiernos, para no comprometer su sostenibilidad. Para alcanzar esto, la presente nota propone discutir los temas asociados a la introducción de mecanismos que permiten impulsar la transición abriendo espacios fiscales, como mecanismos de fijación de precios de carbono, como los impuestos al carbono o los permisos negociables de emisión de carbono. Adicionalmente, se propone la posibilidad de reducir los subsidios a energéticos con grande emisiones o aumentar la eficiencia de los instrumentos con diseños más focalizados, aprovechando el contexto de bajos precios internacionales de la energía.