Analisi delle perdite in un impianto per la lavorazione di bentonite

Questo lavoro ha inizio con l'analisi del processo produttivo e l'individuazione dei parametri che influenzano la capacità produttiva di ciasuna sezione del reparto Bentec, società controllata da Laviosa Chimica Mineraria. Lo studio dell'andamento nel tempo del valore assunto dai parametri nell'anno 2006 ha rappresentato il punto di partenza per la definizione della capacità produttiva effettiva delle sezioni di impianto, relativamente alle diverse tipologie di prodotti realizzati. L'analisi della produttività è stata condotta stabilendo delle relazioni tra i parametri e assegnando agli stessi il valore ricavato dalla media dei valori assunti dal parametro nel periodo di riferimento. Per ciascuna sezione e produzione sono stati inoltre definiti, sulla base di alcune ipotesi, i valori teorici di produttività con l'obiettivo di integrare i risultati delle due differenti analisi, quantificare lo scostamento tra i valori teorici e reali, determinare le cause che lo hanno generato e stabilire l'indice di utilizzo della capacità produttiva disponibile in modo da fornire una guida per attuare interventi di miglioramento orientati all'aumento della produttività

Peningkatan hasil belajar satuan panjang kelas II SDN Babarsari melalui media pembelajaran tangga satuan panjang

Latar belakang penelitian ini mengenai hasil belajar peserta didik pada pembelajaran tematik muatan Matematika materi satuan panjang kelas II SD Negeri Babarsari yang masih rendah, sehingga diperlukan perbaikan agar hasil belajar peserta didik dapat meningkat. Penelitian ini bertujuan untuk meningkatkan hasil belajar materi satuan panjang kelas II SD Negeri Babarsari melalui media pembelajaran tangga satuan panjang. Penelitian ini merupakan Penelitian Tindakan Kelas (PTK). Subjek penelitian ini adalah peserta didik kelas II SD Negeri Babarsari dengan jumlah 27 peserta didik. Desain penelitian ini terdiri dari dua siklus dengan menggunakan model Kemmis dan Targgart yang terdiri dari perencanaan, tindakan, pengamatan, dan refleksi. Teknik pengumpulan data menggunakan dokumentasi dan tes. Analisis data yang digunakan yaitu deskriptif kuantitatif. Hasil penelitian menunjukkan terdapat peningkatan nilai rata-rata hasil belajar peserta didik dari pra siklus sebesar 43,6 meningkat menjadi 60,4 pada siklus I dan meningkat lagi menjadi 74,2 pada siklus II. Dapat disimpulkan bahwa media pembelajaran tangga satuan panjang dapat meningkatkan hasil belajar peserta didik materi satuan panjang kelas II SD Negeri Babarsari Yogyakarta

PENGEMBANGAN MEDIA DOTAYA (LUDO TATA SURYA) UNTUK MENINGKATKAN HASIL BELAJAR IPA MATERI TATA SURYA PADA SISWA KELAS VI DI KABUPATEN GUNUNGKIDUL

Abstrak Rendahnya hasil belajar IPA materi tata surya dan jarangnya media yang digunakan oleh guru ketika pembelajaran serta belum tersedianya media untuk pembelajaran materi tata surya  merupakan  masalah  kompleks  pembelajaran  IPA  SD.  Penelitian  ini  bertujuan  untuk mengetahui  kelayakan  media  pembelajaran  DOTAYA  untuk  siswa  kelas  VI  SD  Negeri Sendowo  III  berdasarkan  penilaian  dari  ahli  materi  dan  ahli  media  dan  keefektifan  media tersebut  untuk  meningkatkan  hasil  belajar  IPA  materi  tata  surya.  Penelitian  ini  merupakan penelitian  pengembangan  atau  Research  and  Development  (RD)  dengan  model pengembangan ADDIE (Dick Carry, 1996) yang meliputi lima tahap yaitu, tahap analisis (analysis),  desain  (design),  pengembangan  (development),  implementasi  (implementation), dan  evaluasi  (evaluation).  Hasil  penelitian  ini  menunjukkan  bahwa  DOTAYA  layak digunakan  di  sekolah  dasar.  Hasil  validasi  materi  memperoleh  nilai  rata-rata  4,7  dengan katagori “Sangat Baik”, sedangkan hasil validasi media terakhir memperoleh nilai rata-rata 4,25  dengan  katagori  “Sangat  Baik”.  DOTAYA  berhasil  memperbaiki  hasil  belajar  IPA materi tata surya. Hal tersebut ditunjukkan dengan persentase ketuntasan hasil belajar posttest, yaitu 66,67%. Persentase ini lebih besar daripada persentase ketuntasan hasil belajar pretest, yaitu 26,67%. Kata kunci: Media, Ludo, Tata Surya.  Abstract Low science achievement about solar system is concerning. Teachers rarely use learning media, and the media are rarely available. This research aims to determine the appropriateness of DOTAYA as learning media for the VI graders in SD Negeri Sendowo III and to determine its effectiveness to improve science achievement of solar system. This study is a research and development (RD) with the  ADDIE  model  (Dick    Carry,  1996)  that  includes  five  stages,  namely  analysis,  design, development, implementation, and evaluation. The results show that DOTAYA is appropriate for the sixth  graders.  The  validation  of  the  content  averaged  4.7  (Very  Good),  while  the  validation  of  the media  averaged  4.25  (Very  Good).  The  DOTAYA  has  been  successfully  improved  the  science achievement  on  solar  system.  The  percentage  of  posttest  is  66.67%,  which  is  greater  than  the percentage of pretest (26.67%).  Keywords: Media, Ludo, Solar Syste

Ruthenium arene complexes in the treatment of 3D models of head and neck squamous cell carcinomas

Current chemotherapy for head and neck squamous cell carcinomas (HNSCCs) are based on cisplatin, which is usually associated to severe side effects. In general, the exploration for metal-based alternatives to cisplatin has resulted in the development of a series of ruthenium complexes that are able to produce a safe therapeutic action against some neoplasms, among which are lung and ovarian cancers. Here, we evaluate the efficacy of well defined, easily available and robust ruthenium(II) η6-arene compounds on 3D models of HNSCCs with or without human papillomavirus (HPV) infection and compare their effects to the state-of-the-art RAPTA-C, a promising ruthenium compound with known anti-cancer activity. One of the compounds induces a significant therapeutic action especially on HPV negative carcinoma. Besides viability and repopulation evaluations, we performed quantitative analysis of the internalized Ru compounds to further validate our findings and elucidate the possible mechanisms of action. These results show that Ru arene compounds represent a promising alternative for the treatment of HNSCCs and pave the way for the composition of innovative (co)therapies

Texture and Phase Recognition Analysis of β-NaYF4 Nanocrystals

Texture and phase recognition analysis (TPRA) based on electron nanodiffraction technique is used to characterize the geometry of up-conversion nanocrystals (UCNCs) synthesized by the common thermal-decomposition protocol in the presence of a stoichiometric amount of NH4F. Here, we confirmed experimentally that despite the apparently different shapes of samples (hexagons, rods, and cubes), all the nanocrystals are actually β-phase hexagonal prisms. This is of relevance since many biological features of nanostructures, such as cellular internalization and cytotoxicity, are governed by their geometry. In addition, reproducibility in biological experiments is paramount

Photothermal effect by NIR-responsive excretable ultrasmall-in-nano architectures

Here, we report: (i) the straightforward production of narrow-NIR-absorbing gold ultrasmall-in-nano architectures (tNAs), and (ii) their suitability as excretable platforms for photothermal therapy upon CW-irradiation at 808 nm. These findings are a significant step toward the translation of metal nanotheranostics to cancer treatments

A New Twist in the Photophysics of the GFP Chromophore: A Volume-Conserving Molecular Torsion Couple

The simple structure of the chromophore of the green fluorescent protein (GFP), a phenol and an imidazolone ring linked by a methyne bridge, supports an exceptionally diverse range of excited state phenomena. Here we describe experimentally and theoretically the photochemistry of a novel sterically crowded nonplanar derivative of the GFP chromophore. It undergoes an excited state isomerization reaction accompanied by an exceptionally fast (sub 100 fs) excited state decay. The decay dynamics are essentially independent of solvent polarity and viscosity. Excited state structural dynamics are probed by high level quantum chemical calculations revealing that the fast decay is due to a conical intersection characterized by a twist of the rings and pyramidalization of the methyne bridge carbon. The intersection can be accessed without a barrier from the pre-twisted Franck-Condon structure, and the lack of viscosity dependence is due to the fact that the rings twist in the same direction, giving rise to a volume-conserving decay coordinate. Moreover, the rotation of the phenyl, methyl and imidazolone groups are coupled in the sterically crowded structure, with the methyl group translating the rotation of one ring to the next. As a consequence, the excited state dynamics can be viewed as a torsional couple, where the absorbed photon energy leads to conversion of the out-of-plane orientation from one ring to the other in a volume conserving fashion. A similar modification of the range of methyne dyes may provide a new family of devices for molecular machines, specifically torsional couples

Unexpected Records of Newborn and Young Sharks in Ligurian and North Tyrrhenian Seas (North-Western Mediterranean Basin)

Between 2007 and 2022, 112 specimens of newborn and young pelagic sharks were recorded in the waters of Tuscany Region, in the South Ligurian–North Tyrrhenian Seas (north-western Mediterranean basin). The sharks belonged to the Carcharhinus plumbeus (n = 14), Prionace glauca (n = 66), Isurus oxyrinchus (n = 16), Mobula mobular (n = 5) Alopias vulpinus (n = 7) and Hexanchus griseus (n = 4) species. Each animal was correctly identified thanks to the photographs or videos collected. All specimens were incidentally captured with set nets in inshore shallow waters, except bluntnose six-gill sharks, which were bycatch of deep-water bottom-trawl fishery. Body mass, sex, total length and biometric measurements were recorded in 34 baby sharks following the Mediterranean Large Elasmobranches Monitoring (MEDLEM) protocol. The presence of very evident and often non-healed umbilical scar confirmed that some of the sample specimens were newborn. Further confirmation came from the comparison between the total length observed and the size at birth known for the sampled species as reported in the literature. Some baby sharks were preserved in the Museums of Natural History of Pisa and Florence University collections. The importance of the coastal area studied as a possible shark nursery is discussed

Total- and semi-bare noble metal nanoparticles@silica core@shell catalysts for hydrogen generation by formic acid decomposition

Catalysts are involved in a number of established and emerging chemical processes as well as in environmental remediation and energy conversion. Nanoparticles (NPs) can offer several advantages over some conventional catalysts, such as higher efficiency and selectivity. Nowadays, versatile and scalable nanocatalysts that combine activity and stability are still lacking. Here, we report a comprehensive investigation on the production and characterization of hybrid nano-architectures bringing a partial or total bare surface together with their catalytic efficiency evaluation on, as a proof-of-concept, the formic acid decomposition reaction. In this regard, formic acid (FA) is a convenient and safe hydrogen carrier with appealing features for mobile applications, fuel cells technologies, petrochemical processes and energetic applications. Thus, the design of robust catalysts for FA dehydrogenation is strongly demanded. Due to this, we produced and evaluated nano-architectures with various equilibrium between the size-increase of the active part and the barer catalytic surface. Overall, this work paves the way for the development of new approaches for green energy storage and safe delivery