Literatura académica sobre el tema "Flussi Secondari"

The word „SPRACH-FLUSS“ (flow of language), depicts images of flowing rivers and streams; babbling, gurgling, murmuring along to their destination. They encounter obstacles, turn corners and meander but undeniably reach their goal. SPRACH-FLUSS was a project held in the Sub-Saharan region of Africa in the years 2008 and 2009. 120 pupils and their teachers from 16 countries in Africa took part in these work-shops organised by the Goethe Institute in Johannesburg in conjunction with the Institute for Theatre and Media at the University of Hildesheim in Germany. Of these 120, 20 were invited to put what they learned to use, in a ‘meet-and-greet’ workshop in the Robert-Bosch secondary school in Hildesheim. The high point of this workshop was a stage performance at the Berlin Academy of Art, called „Sprachen ohne Grenzen“ (Languages without Borders). The aim of the workshops, both in Africa and Germany, was for the pupils and teachers to experience through descriptive games, communication training, body work and personality development, a livelier, more enjoyable and more effective method of learning and teaching German. The participants experienced the German language as an international means of communication, during the various interactive exercises they turned corners and meandered but worked hard ...

I disturbi dell'equilibrio idro-salino risultano estremamente comuni nei pazienti ospedalizzati, in particolar modo in quelli critici. L'ipernatremia, che può essere secondaria a sovraccarico di sodio o a perdita di fluidi ipotonici, può contribuire significativamente alla già importante morbilità e al rischio di morte di questa categoria di pazienti. Questo disturbo richiede pertanto una diagnosi tempestiva e può essere corretto con un intervento appropriato e con il trattamento dei fattori predisponenti che ne sono alla base.

The article addresses the problem of the functional purpose of shaft-type furnaces with chimneys found at the Late Bronze Age sites of Northern Eurasia. This category of thermal engineering structures became widespread in the eastern wing of the West Asian (Eurasian) metallurgical province. Thermal sets with flue channels are physical evidence of the implementation of technological algorithms of the pastoral model of metal production based primarily on multistage processing of secondary copper sulfides. Shaft furnaces with flues of the Ural-Kazakhstan region are functionally similar to the more structurally simple fi re pits-furnaces present in the structure of mining and processing complexes of the steppe Cis-Ural region. They were intended for decrepitation, pyrotechnic enrichment, and refining of ore protolith during a long fi re setting using brushwood and wood fuel at relatively low temperatures in the range of 600–800 °C. The degree of complexity of thermal engineering structures was determined by the nature of the raw materials used. Ordinary fi re pits turned out to be acceptable for ore-bearing complexes in the copper shales and sandstones of the steppe Cis-Ural region. The ores of the ultrabasic deposits of the Ural-Mugodzhar region were difficult to be processed and required the use of mine furnaces with flues, which were also characteristic of the metal production centers of the Kazakhstan mining and metallurgical region. Further improvement of thermal engineering structures with flue channels was due to the need to overcome the raw material crisis caused by the exhaustion of available sulfide reserves in secondary enrichment zones within ultrabasic deposits, and copper shale ore occurrences at the end of the Bronze Age. It required the transition to the use of chalcopyrite and greatly contributed to the discovery of iron metallurgy.

Bridging concerns from human-computer interaction (HCI) and media studies, this essay theorizes deepfake images in terms of their phenomenological implications: the extent to which they enfold the human viewer in a world of the otherwise unseen. Drawing on comparative phenomenology of Vilém Flusser and Louis Bec, we focus on variational autoencoders (VAEs). We contend that the processes underlying deepfake image construction, as much as deepfake images themselves, evidence a parallel, prosthetic, and computational phenomenology: a study of “that which appears” to a computer, and which appears secondarily to a user-human as image. We use the example of VAEs to argue for the emergence of a second-order, received phenomenology of the augmented human as we reside in an increasingly computational world. Keywords: deepfake, computer vision, augmented reality, computer phenomenology, magic phenomenology, machine shamanism

L'esplorazione funzionale della carotide extracranica è venuta ad assumere un rilievo clinico sempre maggiore di pari passo al progredire delle conoscenze sulla fisiopatologia della insufficienza cerebrovascolare. Parallelamente alla profilassi primaria, volta al controllo dei fattori di rischio cardiovascolare, è stata sottolineata l'importanza di una efficace profilassi secondaria della malattia, intesa come diagnosi precoce, in fase iniziale o preclinica, in modo da assicurare non solo un adeguato controllo farmacologico nel tempo, ma anche una efficace selezione ed un ampliamento delle indicazioni chirurgiche, per i malati considerati a rischio. In quest'ambito, lo studio non invasivo dei vasi cerebroafferenti con metodiche ad ultrasuoni è tuttora da considerarsi il momento base dell'iter diagnostico. Alla sede favorevole, che consente una valutazione ecotomografica fine ed attendibile della patologia parietale, si aggiunge la possibiltà della esplorazione dei fenomeni dinamici di flusso mediante effetto Doppler. Le apparecchiature Eco-Color-Doppler di ultima generazione consentono insieme un'analisi strutturale delle caratteristiche della placca ateromasica, la determinazione del grado di emodinamicità di una lesione, misure discretamente attendibili di velocità e di portata mediante campionamenti mirati endovascolari, o sull'intero campo di scansione. Esistono tuttavia alcuni limiti nelle possibilità diagnostiche delle metodiche ad ultrasuoni, alcuni dei quali di natura intrinseca (l'elevata operatore-dipendenza, l'attenuazione del fascio determinata dal calcio tissutale), altri legati alla esplorabilità individuale del soggetto che si sottopone all'indagine ed alla sede del distretto in esame: in particolare, la impossibilità di studiare la carotide distalmente all'angolo della mandibola. Tuttavia, nel ruolo di screening e di controllo, nella definizione della patologia aterosclerotica carotidea e degli aspetti emodinamici di una lesione, l'indagine Eco-Doppler è da ritenersi tuttora insostituibile.

RESUMOO presente artigo examina episódios e iniciativas que possibilitaram o agendamento do combate ao racismo e outras demandas do Movimento Negro brasileiro no final do século XX, culminando na política de promoção da igualdade racial. O texto debruça-se em especial sobre a política de educação para as relações étnico-raciais. Uma inovação institucional em termos de política curricular. O aporte teórico alicerça-se na teoria do processo político, no modelo dos múltiplos fluxos e no debate sobre federalismo. A análise efetivou-se mediante o esquadrinhamento de fontes secundárias: a produção acadêmica disponível (artigos, teses e dissertações) e documentos públicos (legislação e planos de elaborados pelos agentes públicos e documentos produzidos pelo Movimento Negro). Os resultados evidenciam que a implementação da política de educação para as relações raciais enfrenta óbices de natureza institucional e política, como, por exemplo, a ausência de uma estrutura de incentivos que promova a adesão dos entes federativos, além de, sobretudo, deparar com o que pretende destruir: o próprio racismo nas mais distintas facetas.Agendamento. Relações Étnico-Raciais. Política Curricular. Inovação Institucional. ABSTRACTThis article examines episodes and initiatives that enabled the topic of fighting racism and other demands from the Brazilian Black Movement to be placed on the agenda in the late 20th century, culminating in policy to promote racial equality. The paper addresses education policy for ethnic-racial relations. This was an institutional innovation in terms of curricular policy. The theoretical contribution is based on political process theory, the multiple flow model and the debate on federalism. The analysis was conducted by investigating secondary sources: the academic production available (articles, theses and dissertations) and public documents (legislation and plans prepared by public officials and documents produced by the Black Movement). The results demonstrate that the introduction of education policy for racial relations faces obstacles of an institutional and political nature, such as the absence of a structure of incentives that promotes adherence by the federative units, and, above all, encountering what it intends to destroy: the distinctive aspects of racism.Agenda Setting. Ethnic/Racial Relations. Curricular Policy. Institutional Innovation. RESUMENEste artículo analiza episodios e iniciativas que permitieron poner en la agenda la lucha contra el racismo y otras demandas del Movimiento Negro Brasileño a fines del siglo XX, culminando con la política de promoción de la igualdad racial. El texto se centra en particular en la política de educación para las relaciones étnico-raciales. Una innovación institucional en términos de política curricular. El aporte teórico se basa en la teoría del proceso político, en el modelo de múltiples flujos y en el debate sobre el federalismo. El análisis se llevó a cabo mediante el escaneo de fuentes secundarias: la producción académica disponible (artículos, tesis y disertaciones) y documentos públicos (legislación y planes elaborados por agentes públicos y documentos elaborados por el Movimiento Negro). Los resultados muestran que la implementación de la política de educación para las relaciones raciales enfrenta obstáculos de carácter institucional y político como, por ejemplo, la ausencia de una estructura de incentivos que promueva la adhesión de entidades federativas, además de, sobre todo, encontrar con que pretende destruir: el racismo mismo en las más diversas facetas.Agendamiento. Relaciones Étnico-Raciales. Política Curricular. Innovación institucional. SOMMARIOQuesto articolo analizza episodi e iniziative che hanno permesso di mettere all'ordine del giorno la lotta al razzismo e altre rivendicazioni del Movimento nero brasiliano alla fine del XX secolo, culminando nella politica di promozione dell'uguaglianza razziale. Il testo si concentra in particolare sulla politica di educazione alle relazioni etnico-razziali. Un'innovazione istituzionale in termini di politica curricolare. Il contributo teorico si basa sulla teoria del processo politico, nel modello dei flussi multipli e nel dibattito sul federalismo. L'analisi è stata condotta scansionando fonti secondarie: produzione accademica disponibile (articoli, tesi e dissertazioni) e documenti pubblici (legislazione e piani preparati da agenti pubblici e documenti preparati dal Movimento Nero). I risultati mostrano che l'attuazione della politica educativa per le relazioni razziali incontra ostacoli di natura istituzionale e politica come, ad esempio, l'assenza di una struttura di incentivi che promuova l'adesione degli Stati, oltre, soprattutto, l'incontro che mira a distruggere: il razzismo stesso nelle più diverse sfaccettature.Pianificazione. Relazioni etnico-razziali. Politica curricolare. Innovazione istituzionale.

ABSTRACT Introduzione Il trauma cranico (TBI – Traumatic Brain Injury) è una delle principali cause di morte e disabilità al mondo. Il danno cerebrale primario è rappresentato dal trauma, mentre il danno cerebrale secondario è l’evoluzione, limitabile, del danno primario. Esso necessita di una gestione precoce, che inizi immediatamente dopo il trauma e che preveda il raggiungimento di precisi target terapeutici correlati ad un miglior outcome. Attualmente le indicazioni per la gestione del TBI provengono dalle Linee Guida del 2008 (LG 2008), ma in questi anni la letteratura scientifica si è arricchita di molti studi che costituiscono un importante fonte di aggiornamento e miglioramento della gestione preospedaliera dei pazienti con trauma cranico. Scopo dello studio: valutare l’aderenza alle raccomandazioni delle LG 2008 e della più recente letteratura sulla gestone del TBI moderato e severo. Metodo: studio retrospettivo monocentrico. Criteri di inclusione: età > 18 anni, GCS <12, soccorsi da HEMS FVG o Automedica ASUFC. Periodo: 01/05/20118 – 30/04/2020. Raccolta parametri e informazioni cliniche da schede di intervento e sistema informatico ospedaliero. Risultati: 82 pazienti arruolati, 59 (72%) maschi. Età media 58.1±21.3 anni. Il valore medio di H-AIS è stato 3±1.5. A T1: 51(62.2%) TBI severi, 30(36.6%) moderati e 1(1.2%) lieve poi evoluto in moderato. Aderenza di rilevazione del GCS/pupille variabile da 100%/40.2% a 57.1%/17.1%. Aderenza di rilevazione di SpO2/sAP/etCO2 variabili tra 82.9%/89%/45.5% e 53.7%52.4%/46.3%. Temperatura rilevata al massimo nel 2.4% dei casi. Aderenza terapeutica >90% per O2 terapia, <90% per intubazione, <80% per fluidoterapia e vasopressori, <50% per etCO2, nulla per normotermia. Raggiungimento target terapeutici: >95% per SpO2 e sAP>90mmHg, 85.5% per sAP>110mmHg, <50% per etCO2. Conclusioni: necessità di migliorare aderenza di rilevazione di temperatura e pupille, mediante sensibilizzazione del personale e introduzione di scheda di missione unica. Migliorabile il raggiungimento del target pressorio utilizzando sia fluidi che vasopressori. Da implementare la rilevazione dell’etCO2 come guida nell’impostazione della ventilazione.

Electric vehicles (EV) have been introduced in the recent years due to public awareness of the effect of gas emission from traditional cars and the extinction of petroleum natural resources. For charging EV, dynamic wireless charging is considered in this paper. This is because it is more convenient and saves charging time since it charges the electric vehicle while moving. The main challenge of this process is to maintain a high amount of power transfer from primary to secondary coil. One of the factors contributing to a good power transfer is the size of the coil [1]. There are various designs of coil for wireless charging of electric vehicles (EV). Among the most common designs are circular pad (CP), rectangular pad (RP), double-D pad (DDP), and double-D quadrature pad (DDQP). In this paper, circular pad (CP) is chosen for use, due to its simplicity in design and good electrical and magnetic properties. Three different coil pair sizes are tested to find the most suitable coil pair for the primary and secondary pads that has the maximum power transfer and is least sensitive to misalignment. The magnetic properties have been investigated to obtain the highest value of magnetic flux. The geometry design of the pads and simulation was done using COMSOL Multiphysics software. From the simulation, it was found that the unsymmetrical coil pair gives high magnetic strength when the outer diameters of the primary and secondary coils have the same value. ABSTRAK: Kenderaan Elektrik (EV) telah diperkenalkan sejak beberapa tahun ini hasil kesedaran awam tentang kesan pembebasan gas dari kenderaan lama dan pengurangan sumber asli petroleum. Kajian ini berkaitan pengecas dinamik tanpa wayar bagi mengecas EV. Ini kerana pengecas ini lebih sesuai dan jimat masa mengecas kerana kenderaan elektrik dicas ketika bergerak. Cabaran utama proses ini adalah mengekalkan pemindahan tenaga yang tinggi daripada gegelung primer kepada gegelung sekunder. Salah satu faktor bagi mendapatkan pemindahan tenaga yang tinggi adalah saiz gegelung wayar [1]. Terdapat pelbagai bentuk gegelung bagi mengecas kenderaan elektrik (EV) tanpa wayar. Antaranya adalah pad membulat (CP), pad segiempat tepat (RP), pad berganda-D (DDP), dan pad kuadratur berganda-D (DDQP). Kajian ini telah menggunakan pad membulat (CP) kerana reka bentuknya yang ringkas dan ia mempunyai sifat elektrikal dan magnatik yang baik. Tiga pasang gegelung berbeza telah diuji bagi mendapatkan pasangan gegelung pad primer dan sekunder yang paling sesuai di mana ianya mempunyai pemindahan tenaga maksima dan paling kurang sensitif pada ketidakjajaran. Sifat magnet telah diuji bagi mendapatkan nilai fluks magnet tertinggi. Rekabentuk geometri pad dan simulasi telah dijalankan menggunakan perisian Multifizik COMSOL. Hasil simulasi mendapati pasangan gegelung yang tidak simetri telah menghasilkan kekuatan magnetik tertinggi apabila diameter luaran gegelung primer dan sekunder mempunyai nilai sama.

Background:The Rotterdam Early Arthritis Cohort (REACH) rule [1] and Clinical Arthritis RulE (CARE) [2] are both evidence-based and easy-to-use methods developed to identify the presence of inflammatory arthritis (IA) in patients suspected by their general practitioner (GP). However, the clinical utility of both models in daily clinical practice in an independent primary care setting has not yet been established. While developed for recognizing IA, we believe that it is also important that the broader spectrum of inflammatory rheumatic diseases (IRDs) is correctly classified from primary care, to facilitate appropriate referral towards outpatient rheumatology clinics.Objectives:The primary objective was to determine the diagnostic performance and clinical utility of the REACH and CARE referral rules in identifying IA in an independent population of unselected suspected patients from primary care. Secondly we will assess the diagnostic performance and clinical utility of both models in identifying IRDs.Methods:This prospective observational diagnostic study consisted of adults newly suspected by their GP for the need of referral to the rheumatology outpatient clinic of the Maasstad Hospital in Rotterdam. Primary outcome was IA, consisting of rheumatoid arthritis, axial spondylitis and psoriatic arthritis. Secondary outcome was IRD, defined as IA plus arthritis in systemic disorders such as systemic lupus erythematosus, systemic sclerosis and morbus sjögren. Rheumatologist diagnosis was used as gold standard. To evaluate the clinical performance of the REACH and CARE referral rules in this population, diagnostic accuracy measures were investigated using the Youden index (J) [3]. Moreover, a net benefit approach [4] was used to determine clinical utility of both rules when compared to usual care.Results:This study consisted of 250 patients (22.8% male) with a mean age of 50.8 years (SD 13.9 years). In total 42 (17%) patients were diagnosed with IA and 55 (22%) with an IRD. Figure 1 presents the diagnostic performance in IA (Figure 1A) and in IRD (Figure 1B). For the primary outcome, the REACH model shows an AUC of 0.72 (95% CI 0.64-0.80) and the optimal cut-off point is indicated (J). The CARE model shows an AUC of 0.82 (95% CI 0.75-0.88) and at J there is a somewhat higher sensitivity and specificity. When taking the broader spectrum of IRDs as outcome, the AUC was 0.66 (95% CI 0.58-0.74) for the REACH and 0.76 (95% CI 0.69-0.83) for the CARE model. The net benefit analysis with either IA or IRD as outcome showed that the CARE was of the highest clinical value when compared to usual care.Conclusion:Both the REACH and CARE model showed a good diagnostic performance for detecting IA in an independent population of unselected suspected patients from primary care. Although not specifically developed to recognize the entire spectrum of IRDs, the CARE shows a good performance in doing so. When evaluating clinical utility, we see that both rules have a net benefit in recognizing IA as well as IRDs compared to usual care, however the CARE shows superiority over the REACH. By using the CARE, over half of all suspected patients can be withheld from expensive outpatient rheumatology care, implied by the high specificity of 70%. These results support the idea that incorporating these easy-to-use methods into primary care could lead to providing patients the right care at the right place and improving value based health care.References:[1]ten Brinck RM, van Dijk BT, van Steenbergen HW, le Cessie S, Numans ME. Development and validation of a clinical rule for recognition of early inflammatory arthritis. BMJ Open; 2018: 8[2]Alves, C. Improving early referral of inflammatory arthritis. In Early detection of patients at risk for rheumatoid arthritis – a challenge for primary and secondary care; 2015: 27-38 Ridderkerk, the Netherlands.[3]Fluss R, Faraggi D, Reiser B. Estimation of the Youden Index and its associated cutoff point. Biom J; 2005: 47(4): 458-472[4]Vickers AJ, Elkin EB. Decision curve analysis: a novel method for evaluating prediction models. Med Decis Making; 2006: 26(6): 565-574Disclosure of Interests:None declared

Il seno cavernoso può essere interessato da patologia neoplastica (primitiva e secundaria), infiammatoria e vascolare. Tutte queste entità, ad esclusione delle fistole carotido-cavernose dirette, si manifestano con una clinica analoga, rendendo la diagnosi dipendente fondamentalmente dalle tecniche di imaging. Attualmente le metodiche più utili nello studio del seno cavernoso sono la tomografia computerizzata e la risonanza magnetica che, con le tecniche di angio-TC ed angio-RM, permettono anche uno studio simil-angiografico della regione di interesse. L'arteriografia selettiva rimane tuttora la tecnica gold standard nello studio delle patologie vascolari (aneurismi della carotide interna e fistole carotido-cavernose). La flebografia sovraorbitaria trova attualmente utilizzo esclusivo nella diagnosi della sindrome di Tolosa Hunt con RM negativa e talvolta nella terapia endovascolare di fistole artero-venose. I tumori primitivi più frequenti sono i meningiomi, mentre i neurinomi del seno cavernoso sono estremamente rari. I meningiomi insorgono dal rivestimento durale del seno e si manifestano, sia alla TC che alla RM, come lesioni ben delimitate con un'impregnazione precoce, intensa ed omogenea. I neurinomi del seno cavernoso possono derivare dal III, dal IV, dal V o dal VI nervo cranico e possono insorgere primitivamente nel seno cavernoso o, più frequentemente, negli spazi cisternali interessando il seno sviluppandosi lungo il nervo. La diagnosi differenziale deve essere posta soprattutto tra il meningioma ed il macroadenoma ipofisario a sviluppo laterosellare (il più frequente tumore secondario). Il principale criterio riguarda l'interessamento della carotide interna che viene frequentemente stenotizzata dai meningiomi, mentre può essere circondata e dislocata dai macroadenomi, senza però apprezzare significative riduzioni del suo lume. Il seno cavernoso può essere interessato per contiguità anche da due neoplasie della base cranica: il carcinoma del rinofaringe ed il cordoma. Le metastasi del seno cavernoso si possono instaurare per via ematogena, liquorale o perineurale. Determinano generalmente aumento di volume del seno, non hanno un segnale RM caratteristico e devono essere messe in diagnosi differenziale con le patologie infiammatorie. Queste comprendono la sindrome di Tolosa Hunt e le affezioni granulomatose croniche (sarcoidosi, granulomatosi di Wegener). La prima è caratterizzata da dolore retroorbitario, paralisi dell'oculomotore ed iperestesia trigeminale sostenute da un'infiammazione del seno ad eziologia sconosciuta. Le immagini di RM possono essere del tutto negative ed in tali casi può essere utile per raggiungere la diagnosi la flebografia. Un valido criterio diagnostico per le patologie infiammatorie è rappresentato dalla drammatica remissione della sintomatologia e del quadro radiologico in seguito a terapia steroidea. Gli aneurismi della carotide interna sono classificati in base alle dimensioni: se di diametro superiore ai 2,5 cm vengono definiti giganti. Questi hanno parete trombizzata, scarsa tendenza alla rottura e si manifestano clinicamente con sintomi da compressione dei nervi che decorrono nella parete od all'interno del seno cavernoso. Nella diagnosi di queste formazioni la semeiotica TC e RM, tra loro complementari, rivestono un ruolo importante. Il criterio fondamentale è però dato dalla dimostrazione della natura vascolare della lesione, ottenibile con le tecniche di angio-TC e angio-RM e l'arteriografia selettiva. Le fistole carotido-cavernose dirette sono anomale comunicazioni ad alto flusso tra la carotide interna ed il seno cavernoso Sono caratterizzate da una presentazione clinica improvvisa ed imponente e sono facilmente valutabili con TC, angio-TC, RM, angio-RM ed arteriografia digitale. Le fistole carotido-cavernose indirette corrispondono a fistole arterovenose durali ed hanno di solito una clinica sfumata ed un decorso subdolo. La loro diagnosi con TC, angio-TC, RM ed angio-RM è più difficile essendo spesso i reperti suggestivi di tali condizioni rappresentati solo da una dilatazione della vena orbitaria di drenaggio. L'arteriografia oltre a confermare la diagnosi rappresenta anche l'indagine indispensabile per la programmazione terapeutica endovascolare o chirurgica.

Lo scopo di questo lavoro di tesi, svolto presso la Fores Engineering di Forlì, società del gruppo Rosetti Marino, è di studiare il sistema di raffreddamento di un gas di sintesi ad alta temperatura, andando a supportare la progettazione di dettaglio sviluppata da Fores. Il raffreddamento avviene in due apparecchiature poste in serie: un quencher che porta il gas da 1100 °C a 500 °C, e, a seguire, uno scambiatore (secondary cooler) che raffredda il gas fino a 300 °C. Durante l’esperienza di tirocinio è stato richiesto di dimensionare entrambe le apparecchiature, tenendo presenti alcuni vincoli progettuali richiesti dal processo. Il fluido di raffreddamento è acqua in pressione che evapora parzialmente, per cui è stato necessario considerare tutte le problematiche e gli aspetti peculiari connessi a queste particolari condizioni. Il quencher fa parte di un impianto pilota oggetto di revamping e svolge un ruolo fondamentale all’interno del processo in quanto il successo di quest’ultimo è strettamente correlato al modo in cui viene condotto il raffreddamento. N.b. Poiché questo impianto è oggetto di brevetto, in questa tesi non sarà esplicitato niente che possa tradire il segreto industriale: pertanto non verranno riportate informazioni specifiche come, ad esempio, le sostanze coinvolte, ma solamente informazioni generali che permettano comunque di ottenere una buona descrizione del sistema.

Lo scopo della tesi era valutare l’impatto di alcune condizioni di stress sulla risposta fisiologica di Lactobacillus sakei, una specie appartenente al gruppo dei lattobacilli con la capacità di dominare il microbiota di prodotti carnei fermentati anche quando gli zuccheri esosi (glucosio) o pentosi (ribosio) sono esauriti, utilizzando altri substrati (aminoacidi, piruvato) per ottenere energia tramite vie metaboliche secondarie. Per studiare questi aspetti, il ceppo target (L. sakei Chr82, starter commerciale) è stato pre-coltivato in presenza di glucosio o ribosio ed inoculato in terreno sintetico contenente tutti gli aminoacidi in forma libera. I risultati hanno mostrato che il metabolismo degli aminoacidi era influenzato dalla presenza degli zuccheri, con arginina, cisteina e serina consumati in maniera significativa. Sulla base di questi risultati, nella seconda fase il ceppo è stato inoculato in tampone fosfato a pH 7 o 5, addizionando i suddetti aminoacidi o acido piruvico (punto di partenza per diverse vie metaboliche per la produzione di energia e composti aromatici). I dati dei conteggi hanno mostrato una minore sopravvivenza a pH 5, soprattutto in cellule pre-coltivate con glucosio. L’analisi citofluorimetrica ha evidenziato una maggiore vitalità, ad eccezione del campione con cisteina dopo 6 ore di incubazione. La permeabilità della membrana cellulare era in generale maggiore a pH 7, mentre la depolarizzazione era maggiore a pH 5. Nei campioni con acido piruvico questi valori erano decisamente più bassi, ad indicare una maggiore integrità cellulare. I risultati relativi agli acidi organici hanno mostrato infatti un consumo di piruvato pari a circa il 50%, suggerendo che esso venga impiegato come substrato per vie metaboliche volte a ricavare energia favorendo la sopravvivenza microbica. I risultati ottenuti possono fornire informazioni utili per ottimizzare l'utilizzo di L. sakei nell’industria dei salumi fermentati.

I rifiuti rappresentano una sfida a livello ambientale, sociale ed economico: se da un lato evocano immagini negative, spesso diffuse dai mass media in relazione a reati ambientali, dall’altro rappresentano una risorsa preziosa per l’industria nel caso in cui vengano sottoposti a riutilizzo, riciclaggio e recupero di materia ed energia, anche su scala globale a seguito di movimentazioni transfrontaliere. Il presente studio si articola tra il tema normativo, relativo alla gestione e movimentazione dei rifiuti speciali, argomenti tecnico/procedurali, in merito ai controlli ambientali, e valutazioni di natura economico/ambientale, riguardanti le motivazioni a sostegno dei flussi e delle rotte dei rifiuti, conciliando la materia ambientale con quella economico/politica. Il percorso parte da una “fotografia” della gestione nazionale e locale dei rifiuti speciali, per focalizzarsi sui flussi di rifiuti e materie prime secondarie, così come rilevati dagli enti localmente preposti alla vigilanza ambientale, contestualizzati nella realtà produttiva veneta e nello scorcio del Porto di Venezia, elaborati al fine di un apporto propositivo alla strategia di repressione dei traffici illeciti di rifiuti.

Despite significant efforts have been directed toward reducing waste generation and encouraging alternative waste management strategies, landfills still remain the main option for Municipal Solid Waste (MSW) disposal in many countries. Hence, landfills and related impacts on the surroundings are still current issues throughout the world. Actually, the major concerns are related to the potential emissions of leachate and landfill gas into the environment, that pose a threat to public health, surface and groundwater pollution, soil contamination and global warming effects. To ensure environmental protection and enhance landfill sustainability, modern sanitary landfills are equipped with several engineered systems with different functions. For instance, the installation of containment systems, such as bottom liner and multi-layers capping systems, is aimed at reducing leachate seepage and water infiltration into the landfill body as well as gas migration, while eventually mitigating methane emissions through the placement of active oxidation layers (biocovers). Leachate collection and removal systems are designed to minimize water head forming on the bottom section of the landfill and consequent seepages through the liner system. Finally, gas extraction and utilization systems, allow to recover energy from landfill gas while reducing explosion and fire risks associated with methane accumulation, even though much depends on gas collection efficiency achieved in the field (range: 60-90% Spokas et al., 2006; Huitric and Kong, 2006). Hence, impacts on the surrounding environment caused by the polluting substances released from the deposited waste through liquid and gas emissions can be potentially mitigated by a proper design of technical barriers and collection/extraction systems at the landfill site. Nevertheless, the long-term performance of containment systems to limit the landfill emissions is highly uncertain and is strongly dependent on site-specific conditions such as climate, vegetative covers, containment systems, leachate quality and applied stress. Furthermore, the design and operation of leachate collection and treatment systems, of landfill gas extraction and utilization projects, as well as the assessment of appropriate methane reduction strategies (biocovers), require reliable emission forecasts for the assessment of system feasibility and to ensure environmental compliance. To this end, landfill simulation models can represent an useful supporting tool for a better design of leachate/gas collection and treatment systems and can provide valuable information for the evaluation of best options for containment systems depending on their performances under the site-specific conditions. The capability in predicting future emissions levels at a landfill site can also be improved by combining simulation models with field observations at full-scale landfills and/or with experimental studies resembling landfill conditions. Indeed, this kind of data may allow to identify the main parameters and processes governing leachate and gas generation and can provide useful information for model refinement. In view of such need, the present research study was initially addressed to develop a new landfill screening model that, based on simplified mathematical and empirical equations, provides quantitative estimation of leachate and gas production over time, taking into account for site-specific conditions, waste properties and main landfill characteristics and processes. In order to evaluate the applicability of the developed model and the accuracy of emissions forecast, several simulations on four full-scale landfills, currently in operative management stage, were carried out. The results of these case studies showed a good correspondence of leachate estimations with monthly trend observed in the field and revealed that the reliability of model predictions is strongly influenced by the quality of input data. In particular, the initial waste moisture content and the waste compression index, which are usually data not available from a standard characterisation, were identified as the key unknown parameters affecting leachate production. Furthermore, the applicability of the model to closed landfills was evaluated by simulating different alternative capping systems and by comparing the results with those returned by the Hydrological Evaluation of Landfill Performance (HELP), which is the most worldwide used model for comparative analysis of composite liner systems. Despite the simplified approach of the developed model, simulated values of infiltration and leakage rates through the analysed cover systems were in line with those of HELP. However, it should be highlighted that the developed model provides an assessment of leachate and biogas production only from a quantitative point of view. The leachate and biogas composition was indeed not included in the forecast model, as strongly linked to the type of waste that makes the prediction in a screening phase poorly representative of what could be expected in the field. Hence, for a qualitative analysis of leachate and gas emissions over time, a laboratory methodology including different type of lab-scale tests was applied to a particular waste material. Specifically, the research was focused on mechanically biologically treated (MBT) wastes which, after the introduction of the European Landfill Directive 1999/31/EC (European Commission, 1999) that imposes member states to dispose of in landfills only wastes that have been preliminary subjected to treatment, are becoming the main flow waste landfilled in new Italian facilities. However, due to the relatively recent introduction of the MBT plants within the waste management system, very few data on leachate and gas emissions from MBT waste in landfills are available and, hence, the current knowledge mainly results from laboratory studies. Nevertheless, the assessment of the leaching characteristics of MBT materials and the evaluation of how the environmental conditions may affect the heavy metals mobility are still poorly investigated in literature. To gain deeper insight on the fundamental mechanisms governing the constituents release from MBT wastes, several leaching experiments were performed on MBT samples collected from an Italian MBT plant and the experimental results were modelled to obtain information on the long-term leachate emissions. Namely, a combination of experimental leaching tests were performed on fully-characterized MBT waste samples and the effect of different parameters, mainly pH and liquid to solid ratio (L/S,) on the compounds release was investigated by combining pH static-batch test, pH dependent tests and dynamic up-flow column percolation experiments. The obtained results showed that, even though MBT wastes were characterized by relatively high heavy metals content, only a limited amount was actually soluble and thus bioavailable. Furthermore, the information provided by the different tests highlighted the existence of a strong linear correlation between the release pattern of dissolved organic carbon (DOC) and several metals (Co, Cr, Cu, Ni, V, Zn), suggesting that complexation to DOC is the leaching controlling mechanism of these elements. Thus, combining the results of batch and up-flow column percolation tests, partition coefficients between DOC and metals concentration were derived. These data, coupled with a simplified screening model for DOC release, allowed to get a very good prediction of metal release during the experiments and may provide useful indications for the evaluation of long-term emissions from this type of waste in a landfill disposal scenario. In order to complete the study on the MBT waste environmental behaviour, gas emissions from MBT waste were examined by performing different anaerobic tests. The main purpose of this study was to evaluate the potential gas generation capacity of wastes and to assess possible implications on gas generation resulting from the different environmental conditions expected in the field. To this end, anaerobic batch tests were performed at a wide range of water contents (26-43 %w/w up to 75 %w/w on wet weight) and temperatures (from 20-25 °C up to 55 °C) in order to simulate different landfill management options (dry tomb or bioreactor landfills). In nearly all test conditions, a quite long lag-phase was observed (several months) due to the inhibition effects resulting from high concentrations of volatile fatty acids (VFAs) and ammonia that highlighted a poor stability degree of the analysed material. Furthermore, experimental results showed that the initial waste water content is the key factor limiting the anaerobic biological process. Indeed, when the waste moisture was lower than 32 %w/w the methanogenic microbial activity was completely inhibited. Overall, the obtained results indicated that the operative conditions drastically affect the gas generation from MBT waste, in terms of both gas yield and generation rate. This suggests that particular caution should be paid when using the results of lab-scale tests for the evaluation of long-term behaviour expected in the field, where the boundary conditions change continuously and vary significantly depending on the climate, the landfill operative management strategies in place (e.g. leachate recirculation, waste disposal methods), the hydraulic characteristics of buried waste, the presence and type of temporary and final cover systems.

The present thesis deals with the generation of innovative design solutions for reducing aerodynamic losses in Low-Pressure Turbines through the combined use of Artificial Neural Networks and CFD (Computational Fluid Dynamics). In particular, a lean model for optimizing blade airfoils in a multi-row environment and the development of a passive control device for reducing secondary losses are presented. The first procedure allows building a 1.5 stage by starting from a single blade profile, which is one of the main focuses of low TRL (Technology Readiness Level) design activities. In the obtained setup, two airfoil aerodynamic optimizations are performed by considering steady and unsteady conditions separately. The evaluation of the unsteady phenomena proves to be critical already at the considered blade design stage. Indeed, such practice allows achieving better aerodynamic performance and reducing the blade count per row. The second part of the thesis explains the blade fence development, which has been performed in collaboration with Avio Aero and Università degli Studi di Genova (UniGE). Such shelf-like devices are applied onto the blade surface to hinder the generation of secondary flows. The blade fence shape is the result of numerical aerodynamic optimizations so that the devices determine the reduction not only of the secondary loss but also of the flow turning deviation at the vane outlet. Such beneficial effects are also confirmed by the results of the experimental campaign conducted by UniGE on linear cascades.

L’Agenda Digitale Europea stabilisce il ruolo chiave delle tecnologie dell’informazione e della comunicazione (TIC) grazie a un mercato digitale unico basato su internet veloce e superveloce e su applicazioni interoperabili, al fine di ottenere vantaggi socioeconomici sostenibili COM(2010)245. Le TIC producono un'innovazione di prodotto e cambiamenti strutturali all'interno di tutto il sistema economico e possiamo affermare che dal punto di vista multisettoriale hanno un ruolo moltiplicativo sulla crescita economica, poiché l’aumento della domanda di TIC stimola a sua volta tutte le altre produzioni. Inoltre come riscontrato in letteratura economica, nelle istituzioni internazionali, nonché confermate dai dati periodici rilasciati dagli uffici statistici nazionali, una maggiore incidenza della popolazione attiva formalmente istruita in associazione con l'adozione delle TIC è altamente correlata ad una crescita robusta, sostenibile ed equa. In questo quadro è importante valutare il ruolo delle TIC nel sistema economico, in particolare verrà analizzato il ruolo delle TIC sia rispetto ad un particolare settore quello della sanità, che dal lato dei soggetti che dovrebbero essere parte attiva nella gestione delle TIC ovvero la situazione delle abilità digitali dei lavoratori dipendenti. Il primo articolo si focalizza sul ruolo delle TIC nella determinazione dell’output del settore sanitario, utilizzando il database WIOD (World Input Output Database), di 24 paesi nell’arco temporale 2000-2014, tenendo conto anche dei differenti sistemi sanitari nazionali. La produzione del settore “Sanità e Servizi Sociali” assume, almeno in alcuni paesi specifici, il ruolo di stimolo all’innovazione che compensa ampiamente quello di peso sul bilancio pubblico. Nel secondo articolo analizziamo come l’uso delle TIC stia progressivamente aumentando nel sistema sanitario italiano e in particolare come l'introduzione del Fascicolo Sanitario Elettronico (FSE), strumento di condivisione dei dati sanitari del singolo cittadino, potrebbe determinare cambiamenti nella produzione sui servizi sanitari. Verranno analizzati gli eventuali cambiamenti strutturali dei processi produttivi e della produzione totale applicando l'Analisi Strutturale di Decomposizione (SDA). La base dati di riferimento sarà la tavola di Input-Output riferita a due diversi periodi al fine di individuare i risultati sia degli effetti tecnologici sia della domanda finale a livello settoriale. Infine l’ultimo articolo ha l’obiettivo di valutare le conseguenze dei cambiamenti nella composizione dell'occupazione per competenza digitale all’interno del flusso di produzione e distribuzione del reddito. Verrà costruita una Matrice di Contabilità Sociale (SAM) che consente di rappresentare le relazioni tra i cambiamenti di produzione delle attività e i cambiamenti di compensazione dei dipendenti per competenze, grado di digitalizzazione e genere. LA SAM sviluppata nel documento è relativa all'Italia nel 2013; il lavoro è disaggregato in competenze formali / non formali / informali e, inoltre, competenze digitali / non digitali. Le abilità digitali del lavoro seguono la definizione di “competenza formale” della Commissione Europea (2000): i) competenza formale a seconda del livello di istruzione e formazione; ii) competenza non formale acquisita sul posto di lavoro e attraverso le attività delle organizzazioni e dei gruppi della società civile; iii) competenza informale non acquisita intenzionalmente durante la vita. In questo quadro è stata introdotta un'ulteriore classificazione di input di lavoro basata sull'uso / non utilizzo di computer collegati a Internet. Sulla base della SAM, è stato implementato un modello multisettoriale esteso. Infine, verrà individuata una struttura adeguata di domanda finale che consente di ottenere i migliori risultati in termini di valore aggiunto distribuiti a lavoratori più qualificati con una elevata competenza digitale.

Il titolo di questo volume rimanda a una realtà presente, spesso drammaticamente, in tutti i territori in cui le culture slave, in diverse fasi storiche, si sono trovate a vivere a contatto con altre etnie. Al di là dei problemi di convivenza, complicati oggi da fenomeni quali globalizzazione e multiculturalismo che dissimulano i conflitti identitari, la storia degli slavi si è sempre intrecciata a quella di altri popoli. È sembrato opportuno dunque proporre il tema, non inedito, dei ‘confini’, che offre ampio spazio di riflessione su una molteplicità di aspetti delle culture slave. Ancora oggi dall’Italia si guarda ai paesi dell’Europa centro-orientale con un certo scetticismo. Le lingue e le tradizioni di quest’area restano poco o niente affatto note. I flussi migratori dei popoli di questi ultimi vent’anni hanno contribuito a creare l’immagine di un’Europa di secondaria importanza, arretrata, che vuole imporsi alla prima. Questo volume collettivo vuole invece mostrare come la nostra identità di europei si riesca a mettere a fuoco, e con difficoltà, solo allargando lo sguardo ad est e imparando la lezione dei territori dell’Europa centro-orientale. Anche se gli slavi occidentali e parte degli slavi meridionali hanno partecipato alla storia occidentale sin dal medioevo e ne sono stati poi divisi dagli eventi storici, si potrà forse forgiare una nuova identità europea solo riflettendo sulle vicende dell’intero mondo slavo, e sperimentando le stesse difficoltà di convivenza (quale è ora anche l’esperienza dell’Europa occidentale) fra residenti e immigrati, culture maggioritarie e minoritarie, identità e alterità.

The 1955 production boom resulted in nearly a million unsold vehicles on dealers’ lots. As a result, automakers scaled back production, resulting in widespread, chronic layoffs for autoworkers. Supplemental Unemployment Benefits were of little help because the programs were not fully funded and most unemployed autoworkers did not meet eligibility requirements. Instead, they struggled to cobble together secondary support systems. Many autoworkers had gone into debt during flush times in 1955 and were now saddled with mortgages, rents, or installment payments without regular income. Detroit floundered while the national economy thrived. More accurately, Detroit's working-class residents suffered while wealthier Detroiters shared in the nation's prosperity. Federal officials and automakers blamed autoworkers, with their high wages and generous fringe benefits, for their predicament.

In this paper, a CFD software package is applied to the performance prediction of a 14-stage centrifugal pump with opposed impeller configuration. In this study, the fluid volumes of the complete multistage pump are simulated together. The CFD model includes not only all the main flow channels from inlet to discharge, but also all the secondary flow passages such as wearing ring leakage and seal flush. The CFD model and the simulation results will be presented and discussed in detail. The CFD prediction will be compared with available experiment data.

The objective was to study the effect of equivalence ratio of secondary stage combustible mixture injected into the cross flow stream of vitiated air in a two staged combustion system on the characteristics of the secondary stage combustion zone. The primary cylindrical combustor equipped with low swirl air blast nozzle operating with kerosene generates vitiated air. A methane injector was flush mounted to the inner surface of the secondary combustor. It was used to inject the premixed methane-air mixtures perpendicular into the crossflow of vitiated air. An optical, double shell, secondary combustor with three optical windows on its outer shell was used to image the secondary stage flames. The inner shell was a quadratic fused quartz tube which acts as a thermal barrier and the outer thick quartz windows mounted in the quadratic stainless steel chamber withholds the pressure. Chemiluminescence imaging technique equipped with ICCD camera was used to image the OH* emissions of the secondary stage flame. The vitiated air was generated at 2 bar and 1700 K. The velocity of the vitiated air in the secondary combustor was 57 m/s. A premixed methane air mixture was injected into the cross flow stream of vitiated air. The momentum flux ratio between the jet and the vitiated air was maintained at 1.4. The equivalence ratio of the premixed methane-air mixture was varied from 0.5 to 1.0. As the equivalence ratio of the secondary stage combustible mixture moves towards stoichiometric condition, the secondary stage combustion zone becomes compact and also the distance between the burner and the combustion zone decreases. The turbulent flame stabilized in the secondary combustor exhibited large scale structures and other unsteady phenomena that require time-resolved computational methods. Large eddy simulations (LES) are well suited to the calculation of such complex flows. The flame was embedded in a strong turbulent flow where auto-ignition and quenching are important, which poses a significant challenge for the reaction modeling. The presumed JPDF turbulent reaction model, which has been proven to be a reliable model for these challenging conditions, was successfully coupled with the LES simulation. The qualitative agreement between the results of simulations and measurements was quite satisfactory.

Abstract The objective of matrix acidizing in sandstone reservoirs using acid systems that contains Hydrofluoric acid (HF) is to widen the pore throats and spaces in order to increase the permeability around the wellbore and also to remove formation damage. One of the major disadvantages of this acid system is the secondary and tertiary reactions, which may end up with precipitations that damage the formation. Because of this, pumping sufficient pre- flush and post-flush volumes of Hydrochloric acid (HCl) is critical to prevent such damaging reactions. However, the placement of such fluids still are a concern in multiple opened layers or long open intervals zones. Stimulating sandstone reservoirs in the Southern fields of the Sultanate of Oman is very challenging, especially in those that exhibit relatively low permeability. These formations, based on petrology work, contains significant amount of clays and feldspars, which make it difficult in the designing process of the acid formulation. A new version of HF acid system was recently developed. It is specially formulated, so it does not require the addition of Hydrochloric acid (HCl) pre-flush. Because of this, it can be pumped as a single stage system. In addition, its higher reactivity allows deeper penetration and it has the ability to minimize secondary reactions and damaging precipitates. Lab testing work was conducted to ensure the effectiveness of this single stage acid system. The results were promising as they show a good improvement in the rock permeability. These results were encouraging to carry field trials in the sandstone reservoirs in Oman Southern fields. Up to now, it has been pumped in these type of sandstones for oil producer wells and for water injector wells. The actual treatment using this system showed increased oil productivity by higher than 60% and higher than 80% in water injectivity. This paper presents the testing, designing and pumping of the single stage acid system, as well as the comparison with the conventional HF acid system in Southern fields of Oman. It outlines the laboratory work and analysis done as well as the field trials.

Predicting unsteady aerodynamics and related phenomena in the vicinity of the stability limit of transonic compressors has been a challenging topic within the turbomachinery community since decades. To improve numerical tools and prediction capabilities the Transonic Compressor Darmstadt Open Test Case has been introduced in order to provide a reliable validation test data set for steady and unsteady compressor aerodynamics. This work investigates the unsteady aerodynamics before the occurrence of rotating stall within the TU Darmstadt OpenStage compressor rotor and introduces unsteady wall pressure data to the Darmstadt Open Test Case. Exemplary pre-stall aerodynamics and stall inception are investigated for nominal (transonic) and part speed (subsonic) operating conditions, comprising the analysis of the unsteady static pressure field at the rotor tip as well as spectral analysis of the corresponding pressure signals during transient throttling maneuvers. To capture the rotor tip flow field, the rotor casing is instrumented with axially arranged flush mounted time-resolving wall pressure transducers. To determine propagation speeds of occurring phenomena, additional circumferentially distributed sensors are taken into account. Vibration monitoring shows no significant flutter or non-synchronous blade vibration, prior to the occurrence of rotating stall. Thus, this work focuses on aerodynamics, such as the interaction of secondary flow and shocks.

Abstract Additive manufacturing (AM) offers access to the entire volume of a printed artifact during the build operation. This makes it possible to embedding foreign components (e.g. sensors, motors, actuators) into AM parts, thus enabling multifunctional products directly from the build tray. However, the process of designing for embedding currently requires extensive designer expertise in AM. Current methods rely on a designer to select an orientation for the embedded component and design a cavity such that the component can be successfully embedded without compromising the print quality of the final part. For irregular geometries, additional design knowledge is required to prepare a shape converter: a secondary piece to ensure a flush deposition surface on top of the embedded component. This research aims to develop a tool to automate these different design decisions for in-situ embedding, thus reducing the need for expert design knowledge. A three-stage process is proposed to 1) find the optimum orientation based on cavity volume and cross-section area, 2) create the necessary cavity geometry to successfully insert the component, and 3) perform a Boolean operation to create the digital design for any requisite shape converter. Performance of the tool is demonstrated with four test cases with varying levels of geometric complexity. These test cases show that the proposed process successfully handles arbitrary embedded geometries, though several limitations are noted for future work.

The objective of this investigation was to study the effect of axially staged injection of methane in the vitiated air cross flow in a two stage combustion chamber on the formation of NOX for different momentum flux ratios. The primary cylindrical combustor equipped with a low swirl air blast nozzle operating with Jet-A liquid fuel generates vitiated air in the temperature range of 1473–1673 K at pressures of 5–8 bar. A methane injector was flush mounted to the inner surface of the secondary combustor at an angle of 30°. Oil cooled movable and static gas probes were used to collect the gas samples. The mole fractions of NO, NO2, CO, CO2 and O2 in the collected exhaust gas samples were measured using gas analyzers. For all the investigated operating conditions, the change in the mole fraction of NOX due to the injection of methane (ΔNOX) corrected to 15% O2 and measured in dry mode was less than 15 ppm. The mole fraction of ΔNOX increased with an increase in mass flow rate of methane and it was not affected by a change in the momentum flux ratio. The penetration depth of the methane jet was estimated from the profiles of mole fraction of O2 obtained from the samples collected using the movable gas probe. For the investigated momentum flux ratios, the penetration depth observed was 15 mm at 5 bar and 5 mm at 6.5 and 8 bar. The results obtained from the simulations of the secondary combustor using a RANS turbulence model were also presented. Reaction modeling of the jet flame present in a vitiated air cross flow posed a significant challenge as it was embedded in a high turbulent flow and burns in partial premixed mode. The applicability of two different reaction models has been investigated. The first approach employed a combination of the eddy dissipation and the finite rate chemistry models to determine the reaction rate, while the presumed JPDF model was used in the further investigations. Predictions were in closer agreement to the measurements while employing the presumed JPDF model; this model was also able to predict some key features of the flow as the change of penetration depth with the pressure.

Abstract Acid stimulation in high-temperature sandstone reservoirs with high clay content can lead to undesired results due to secondary and tertiary reactions between treatment fluids and reservoir clays. Although there have been significant advancements in treating clastic formations over the years, high bottomhole temperature (BHT) coupled with high clay content of up to 35% and subhydrostatic conditions still presents a major challenge. A stimulation workflow to address these challenges was adapted to treat and successfully enhance well production in sandstone reservoirs in southern Pakistan. Candidate wells were selected for acidizing treatments based on declining production trend and identification of significant damage skin. X-ray diffraction tests on core samples indicated presence of acid-sensitive clays and calcite. Due to the risk of precipitation from secondary and tertiary reactions, conventional hydrochloric and hydrofluoric acid treatments were not viable options. Core flow testing was conducted to assess the efficiency of alternative acid systems at the reservoir conditions with BHT above 320°F, validating the selection of a high-performance sandstone acid system that was designed to handle undissolved clays in the critical matrix by helping to bind the clays to the pore surfaces, thus preventing them from migrating and plugging the pore throat during flowback. The matrix stimulation campaign included vertical and deviated dry gas wells, completed with 3 1/2-in. to 4 1/2-in. production tubing and 7-in. liner, with perforated intervals averaging 20 ft. Prior to the main acid treatment, high-pressure rotary jetting across the target intervals was conducted by pumping organic acid via coiled tubing. This wellbore conditioning technique allowed maximizing the acid performance by delivering 360° high-energy fluid to clear the perforations of scale and improve injectivity. The main treatment consisted of an organic acid preflush and a high-performance sandstone acid system as the main fluid, followed by a brine post-flush. Throughout the treatment, nitrogen was added to all fluids to facilitate fluid flowback under subhydrostatic conditions. The wells treated using this matrix stimulation engineered workflow yielded sustained production gains from 3 MMscf/D to 3.5 MMscf/D, exceeding expectations by more than 50% and achieving payback periods less than 20 days. The success of the treatment was largely due to the carefully designed stimulation workflow and its flawless execution. Acidizing high-temperature sandstone reservoirs with 30 to 35% clay content is uncommon. The experience gained in southern Pakistan validates the high-performance sandstone acid system as a reliable option for matrix acidizing in hot, acid-sensitive sandstone reservoirs. It also provides a detailed engineering workflow for candidate selection, treatment design, and job execution and evaluation, which can easily be adapted to regions facing similar challenges.

A centrifugal compressor is often equipped with a vaneless diffuser because the operation range of a vaneless diffuser is wider than the operation range of vaned diffuser, and the geometry of the vaneless diffuser is simple and inexpensive. The flow field after the centrifugal compressor rotor is highly complicated and the velocity is high. A moderate amount of this velocity should be recovered to the static pressure. It is important to study the flow field in the vaneless diffuser in order to achieve guidelines for design and an optimal performance. In this article, the experimental study of the pinch in the vaneless diffuser is conducted. Five different diffuser heights were used, b/b2 = 1, b/b2 = 0.903, b/b2 = 0.854, b/b2 = 0.806 and b/b2 = 0.903 (shroud). In three of the cases, the pinch was made to both walls of the diffuser, hub and shroud, and in one case, the pinch was made to the shroud wall. The total and the static pressure, the total temperature and the flow angle were measured at the diffuser inlet and outlet by using a cobra-probe, kiel-probes and flush-mounted pressure taps. In addition, the static pressure in the diffuser was measured at three different radius ratios. The overall performance, the mass flow, the pressure ratio and the isentropic efficiency of the compressor stage were also monitored. Detailed flow field measurements were carried out at the design rotational speed and at the three different mass flows (close to the surge, design and close to the choke). The isentropic efficiency and the pressure ratio of the compressor stage was increased with the pinched diffuser. The efficiency of the rotor and the diffuser was increased, whereas the efficiency of the volute/exit cone was decreased. The pinch made to the shroud wall was the most effective. The pinch made the flow angle more radial and increased the velocity at the shroud where the secondary flow (passage wake) from the rotor is present.

Thermodynamic and aerodynamic measurements at and near the endwall of turbine vanes were carried out in a linear cascade with a transonic flow field. The investigations were performed in the Windtunnel for Straight Cascades at DLR Go¨ttingen at representative dimensionless engine conditions of Mach and Reynolds number, Ma2is = 1.0 and Re2 = 850 000 respectively. The endwall film cooling configuration consisted of a slot in front of the vanes, film cooling holes inside the vane passages and a groove simulating the slit between two adjacent vane platforms, but there was no coolant leakage from the groove. Laser-Two-Focus velocimetry (L2F) was used to determine local velocities in the vicinity of the endwall. At a much larger number of locations compared to the velocity measurements the L2F-device was utilized as a seeding particle counter which enabled the determination of local coolant concentration. With these concentration measurements the migration of coolant from the different origins could be traced through the vane passage. By extrapolating the measured concentration values to the endwall adiabatic film cooling effectiveness could be obtained. The measurements at the present slot configuration were compared with previous ones [1, 2] where the slot position was closer to the vane entrance. Whereas the coolant ejection at the previous slot position produced a much more intense horse shoe vortex than without coolant, the new slot position causes no increase of secondary flow. This result proves the previous statement that positioning a coolant opening flush near the saddle point of the upstream endwall boundary layer stagnation region should be avoided. The new slot position improved film cooling effectiveness compared to the previous ones even with half the amount of coolant. By investigating the migration of film coolant from the holes inside the vane passage, ineffective holes could be identified and suggestions for improving the film coolant configuration could be given. At one location adiabatic film cooling effectiveness from these aerodynamic measurements could be compared with a thermodynamic measurement using infrared imaging.

Abstract Flow distortions occur at the outlet section of the intake duct owing to its shape properties, which is a component of water-jet propulsion. Since the noticeable influence of intake’s flow characteristics upon propulsive efficiency, it’s necessary to focus on intake duct redesign. In this paper, a systematic methodology for reducing flow distortions and power losses within the intake duct through a shape optimization process was obtained. In addition, the mechanism of flow distortions was also developed. The flush type inlet applied in the marine vessel with the speed of 30 knots was chosen as research project. Four characteristic parameters were set as optimization variables depending on the geometrical relationship of thirteen characteristic parameters referred to the duct longitudinal midsection, which were the ramp angle α, the radius of the upper lip R3, the radius of the lower lip R4 and the lip height h respectively. Subsequently, a sample space was built by Latin Hypercube Sampling (LHS) and the parameters were normalized in the range of 0 to 1. With the commercial software CFX, the numerical simulation was accomplished driven by SST k-ω turbulence model. Multi-objective optimization based on the Non-Dominated Sorting Genetic Algorithm II (NSGA-II) was utilized to minimize the non-uniformity at outlet section and maximize the minimal pressure at lip simultaneously. Moreover, the Radial Basis Function (RBF) neural network was employed to approximate the functional relationship between variables and objectives, which could be applied in the NSGA-II to get the Pareto Front. The minimum non-uniformity point and the trade-off point (The point both satisfies the minimum non-uniformity and the maximum minimal pressure at lip strategically) were selected from the Pareto Front. With regard to the characteristic parameters of the trade-off point, the ramp angle, the radius of the upper lip, the radius of the lower lip and the lip height are 31.91°, 11.42 mm, 400.97 mm and 55.43 mm respectively. Meanwhile, the characteristic parameters of the minimum non-uniformity point are 30.22°, 25.59 mm, 166.65 mm and 89.90 mm respectively. Ultimately, the duct outflow characteristics of prototype and optimization are compared. In terms of the trade-off point, the minimal pressure at lip increases 66.40% to −24488.93 Pa and the non-uniformity has a drop of 4.56% to 0.1571. The non-uniformity of the minimum point is 0.1481 which is reduced by 10.02%. Through the optimization of duct shape, the secondary flow (Dean vortices) is suppressed effectively. This paper is expected to provide a better comprehension of the flow field within the intake duct of water-jet propulsion.