Iodoaminations of alkenes

The activation of alkenes and their subsequent functionalization is a frequently used methodology in synthetic chemistry. This review highlights recent iodine-mediated aminations and elaborates on the various strategies to bring about regio- or stereoselective transformations

Le interazioni onda – struttura: la riflessione ondosa

L’inserimento di una qualsiasi struttura preposta alla protezione costiera (o portuale) incide notevolmente sull’idrodinamica e la morfologia della zona circostante. Conoscere gli effetti che un’opera determinerà sul territorio è il primo elemento che consente di definire il tipo stesso di opera da progettare e governa alle fasi di progettazione stessa. Da ciò nasce l’esigenza di studiare l’interazione delle strutture artificiali con le onde marittime, le correnti e il trasporto solido. Tuttavia, l’analisi dell’interazione tra le onde e le strutture costiere non è uno stru-mento fondamentale soltanto per la progettazione delle opere, ma anche per la messa in sicurezza delle zone di battigia o portuali protette dalle opere stesse. Valutare l’affidabilità di tali opere di difesa, ai fini della rappresentazione dei meccanismi del processo di inondazione delle zone costiere in occasione di mareggiate, necessita della conoscenza e della stima accurata dei fenomeni principali che nascono dall’interazione delle opere con il moto ondoso: la risalita delle onde sul paramento lato mare, la traci-mazione e trasmissione di acqua a tergo delle strutture, la riflessione delle onde che, dopo essersi frante sull’opera, ritornano verso il largo

Le reti neurali artificiali in idraulica marittima

Le reti neurali artificiali (Artificial Neural Networks, ANN) sono algoritmi di analisi dati e di modellazione numerica. Vengono dette “data driven models”, ossia modelli di calcolo basati sul processamento di dati – ottenuti sperimentalmente o prodotti artificialmente – al fine di testare la sensibilità di un certo fenomeno ad alcuni parametri. Le ANN sono particolarmente utili nelle analisi di fenomeni in cui il numero di parametri in gioco è molto elevato, e le relazioni fisiche tra essi sono fortemente non lineari e molto complesse. Dal punto di vista della tipologia di modellazione, le ANN costituiscono una “black-box”, dunque l’algoritmo di calcolo prescinde completamente dallo studio del fenomeno fisico che sta alla base della relazione di causa-effetto tra dati di input e di output; pertanto, le ANN sono in grado di elaborare i dati sperimentali a disposizione (input) e produrre delle predizioni dei valori desiderati (output), ricostruendo artificialmente gli effetti della complessa relazione di causa-effetto incognita. Obbiettivo di tale lavoro è esaminare la struttura caratteristica di una rete neurale e proporre alcuni esempi di ANN impiegati per la modellazione della portata di tracimazione e del coefficiente di trasmissione di strutture costiere, per sottolineare l’adeguatezza di tali strumenti all’impiego in idraulica marittima e presentarli per eventuali successivi utilizzi, quali, ad esempio, la stima del coefficiente di riflessione ondosa, ad oggi non ancora modellato accuratamente

Kajian empiris perpindahan massa oksigen oleh compressed air aerator dengan analisis dimensi=Empirical Study on Oxygen Mass Transfer by Compressed Air

To increase oxygen content in water, a Compressed Air Aerator was used, by process of diffusion with forced convection oxygen was absorbed with a certain rate corresponding to the capability and the magnitude of the existin& power. The objective of this research is to know dominant variables that affect the aerator capability in penetrating the oxygen into the water due to aerator system used, and the relationship betwen those variables. In this research, an empirical approach were used for the solution of the problem and carried out by dimensional analysis with numerical anlysis, program. The results of this research indicated that the performance of Compressed Air Aerator namely the rate of mass transfer coefficient of the oxygen into the water (K) is affected by the air compressed from compressor output (P), the nozle hole diameter (do), density of nozzle number per area unit (r), and depth of the water (H) at conditions of oxygen diffusion coefficient into the water (D), mass density of water (r), surface tension of water (s), viscosity of water (mL), viscosity of air (mG) and acceleration of gravity (g) at held constant. The maximum value of K resulted at P = 50 Psi, do= 1 mm, r = 162/m , dan H = 0.75 m. Betwen the K-observed and K-predicted, by chi-squared test there is not significantly difference at probability 0.032. The equation form of prediction was resulted, after being tested with regression analysis, coefficient of ditermination (R2) = 0.8943. Keyword: oxygen mass transfer - aerator - dimensional analysi

Semi-automatic detection of the overtopping waves and reconstruction of the overtopping flow characteristics at coastal structures

This paper proposes a semi-automatic and customizable procedure for the identification of the overtopping waves based on a threshold-down-crossing analysis of the sea surface elevation signals. The procedure can be applied to 2D experimental and numerical signals, to emerged and submerged structures, with the same accuracy of a human-supervised analysis. The procedure includes an original and innovative algorithm to compare the water level signals at consecutive gauges and couple the waves propagating in between. The coupling algorithm implies a series of original applications of practical relevance, such as: i) the computation of the wave celerity, which is a crucial parameter for the assessment of the structural stability and the hydraulic vulnerability of the landward area; ii) the estimation of the wave overtopping discharge, which can be obtained by integrating the wave celerities with the surface elevations; iii) the description of the wave overtopping characteristics and their evolution over the structure crest; iv) the evaluation of the volumes lost for percolation in permeable structures. The application to new and literature data and the comparison with well-established formulae prove that the results obtained from the identification and coupling procedures are accurate and reliable

Left atrial anomalous muscular band as incidental finding during video-assisted mitral surgery

Congenital fibromuscular bands have been described inleft ventricle or right atrium and have been diagnosed by echocardiography and CT scan. The first report of anomalous band in the left atrium was described in 1897 by Rollestone (1). We hereby present a case of a patient with an incidental finding of left atrial band during a minimally invasive mitral surgery procedure

Implementasi Turbin Angin Tipe Helix Dalam Mendukung Ketersediaan Energi Listrik di Wilayah Wisata Dilem Wilis Trenggalek

Energi angin menjadi salah satu energi terbarukan yang tidak terdegradasi, dan tersebar secara geografis. Pemanfaatan energi angin juga di dukung dengan ditargetkannya bauran energi 23% berasal dari EBT pada 2025 mendatang. Kementrian ESDM (Energi dan Sumber Daya Mineral) RI juga mengatakan bahwa potensi angin di Indonesia sangat tinggi mencapai 978 MW yang tersebar di berbagai daerah di Indonesia. Lokasi Pengabdian Masyarakat yaitu Wisata Dilem Wilis Trenggalek memiliki potensi energi angin yang dapat dimanfaatkan untuk menghasilkan listrik, sehingga perlu diimplementasikan turbin angin tipe helix untuk mendukung ketersediaan energi listrik. Adapaun hasil dari pengabdian ini antara lain: terwujudnya satu unit turbin angin tipe helix sebegai alternatif energi yang bersih dan terbarukan yang dapat menghasilkan listrik sekitar 300 watt; terjadinya transfer teknologi dan pengetahuan khususnya tentang implementasi dan perawatan turbin angin tipe helix. Turbin ini dapat beroperasi dan mulai melakukan pengisian pada kecepatan angin sekitar 3m/detik. Kata kunci— Turbin Angin, Energi Terbarukan Abstract  Wind energy is one of the renewable energies that is not degraded, and is geographically dispersed. The use of wind energy is also supported by the target of 23% of the energy mix coming from NRE in 2025. The Ministry of Energy and Mineral Resources (Energy and Mineral Resources) of the Republic of Indonesia also said that the wind potential in Indonesia is very high, reaching 978 MW spread across various regions in Indonesia. The location of the Community Service, namely Dilem Wilis Trenggalek, has the potential for wind energy that can be used to generate electricity, so it is necessary to implement a helix type wind turbine to support the availability of electrical energy. The results of this service include: the realization of a helix type wind turbine unit as a clean and renewable energy alternative which can generate about 300 watts of electricity; the transfer of technology and knowledge, especially regarding the implementation of helix type wind turbines. This turbine can operate and start charging at a wind speed of about 3m/s. Keywords— Wind turbine, Savonius, Renewable Energ

Synthesis of Tungsten Trioxide/Hydroxyapatite (WO3/HAp) Photocatalyst For Methylene Blue Degradation

Abstract: Dyes have toxic properties and complex chemical structures which become a threat to the ecosystem if it exposes to the environment. A photocatalyst is a semiconductor material that can run a photocatalytic process under UV or visible light to degrade most organic molecules, ideally to H2O and CO2. Tungsten trioxide (WO3) is a visible photocatalyst which could use sunlight irradiation to treat the wastewater pollutant. In this study, WO3 material was hybridized with hydroxyapatite (HAp) through the sol-gel method to degrade methylene blue (MB) synthetic pollutants. The FTIR and SEM-EDX characterization confirmed the presence element of the WO3/HAp hybrid material. The original WO3 and modified WO3/HAp photocatalysts with concentrations of 10, 15, and 20 mg were tested to degrade 15 ppm of 50 ml MB solution under visible light for 4 hours. The highest pollutant degradation was obtained using a 20 mg photocatalyst, which reached the photodegradation efficiency of 73.072% for WO3 and 88.689% for WO3/HAp. The result proved that WO3/HAp hybrid photocatalyst showed higher degradation performance than the unmodified WO3 photocatalyst. The results of this research can be developed for industrial wastewater treatment, including the papermaking, printing and dyeing industries.Abstrak: Zat warna  memiliki sifat beracun dan memiliki struktur kimia  kompleks yang dapat menjadi ancaman bagi ekosistem apabila terpapar ke lingkungan. Fotokatalis heterogen menggunakan semikonduktor yang memicu proses fotokatalitik dengan bantuan sinar UV atau sinar tampak dalam mendegradasi kebanyakan limbah organik, menjadi H2O dan CO2. Tungsten trioksida (WO3) merupakan fotokatalis yang dapat menggunakan cahaya matahari untuk mendegradasi polutan pada air limbah. Pada penelitian ini, WO3 dihibridisasi dengan hidroksiapatit (HAp) melalui metode sol-gel untuk mendegradasi polutan sintetik Methylene Blue (MB). Hasil karakterisasi FTIR dan SEM-EDX mengkonfirmasi unsur-unsur penyusun material  WO3/HAp. Fotokatalis WO3 munri  dan WO3/HAp yang dimodifikasi diuji untuk mendegradasi 15 ppm larutan MB 50 ml di bawah cahaya tampak selama 4 jam dengan konsentrasi 10, 15 dan 20 mg. Degradasi polutan tertinggi diperoleh dengan menggunakan fotokatalis 20 mg yang mencapai efisiensi 73,072% untuk WO3 dan 88,689% untuk WO3/HAp. Hasil tersebut membuktikan bahwa fotokatalis hybrid WO3/HAp menunjukkan kinerja degradasi yang lebih baik daripada fotokatalis WO3 tanpa modifikasi