Academic literature on the topic 'InAs/AlSb LCQ'

La détection sensible et sélective des BTEX et du propane présente un grand intérêt pour les applications environnementales, biomédicales et pétrochimiques. Cependant, la détection de ces composés est compliquée à cause des interférences potentielles, soit entre eux, soit avec d'autres composés. Ce problème peut être résolu par la spectroscopie laser à de grandes longueurs d'onde (13-15 µm), où ils présentent des caractéristiques d'absorption très discriminantes. Pourtant, cette gamme spectrale est pratiquement inexplorée en raison du manque de sources appropriées. Cette thèse vise à combler cette lacune en développant des LCQ émettant à des grandes longueurs d'onde élevées et en exploitant le QEPAS pour une détection ultra-sensible et sélective.Un nouveau design est proposé pour améliorer les performances des LCQ à base d'InAs de grande longueurs d'onde. Cette conception nous a permis de démontrer une densité de courant de seuil record de 0,6 kA/cm2 à 300 K. En outre, une nouvelle technique d'isolation utilisant le SOG est également proposée pour améliorer les problèmes de stabilité du dispositif provoqués par l'altération des propriétés de l'isolation de la résine photosensible (généralement utilisée pour les QCL à base d'InAs) à des températures élevées. Par la suite, des QCL DFB monomodes avec un SMSR > 20 dB et une puissance de sortie optique de l'ordre du mW ont été développé, ciblant les lignes d'absorption de ces gaz. En utilisant ces lasers, un système de détection basé sur le QEPAS a été développé, calibré et caractérisé pour la détection du toluène, du benzène et du propane. Des limites de détection exceptionnellement basses de 113 ppb, 3 ppb et 3 ppm sont atteintes dans une matrice d'azote pur sur un temps d'intégration de 10 secondes. Le système conserve sa sélectivité et sa robustesse, même dans des mélanges de gaz complexes. Enfin, une QCL de 13,71 µm est couplée avec succès à un HCW, où les conditions optimales de couplage, la qualité du faisceau et la perte sont explorées. L'étude confirme la transmission efficace d'une telle longueur d'onde à travers le HCW avec une perte minimale et une qualité de faisceau spatial améliorée
Sensitive and selective sensing of BTEX and Propane is of great interest for environmental, biomedical, and petrochemical applications. However, detecting these compounds poses unique challenges due to potential interferences, either among themselves or from other compounds. This issue can be resolved by using laser spectroscopy in the long-wavelength mid-infrared spectral region (13-15 µm), where they exhibit highly discriminating absorption features. Yet, this wavelength range is almost unexplored due to the lack of suitable sources. This thesis aims to bridge this gap by developing high-performing long-wavelength QCLs and leveraging QEPAS for ultra-sensitive and selective detection.A novel design is proposed to improve the performance of long-wavelength InAs-based QCLs, which allowed us to demonstrate a record-breaking low threshold current density of 0.6 kA/cm2 at 300 K. Additionally, a novel insulation technique using SOG is also proposed to improve device stability issues provoked by the alteration of properties of photoresist insulation (typically used for InAs-based QCLs) at elevated temperatures. Subsequently, single-frequency DFB QCLs with SMSR > 20 dB and optical output power in the mW range operating in the continuous wave regime are developed, targeting the absorption lines of these gasses. Using these DFBs, a sensing system based on QEPAS is developed, calibrated, and characterized for Toluene, Benzene, and Propane detection. Exceptionally low detection limits of 113 ppb, 3 ppb, and 3 ppm are achieved in a pure nitrogen matrix over a 10-second integration time. The system maintains selectivity and robustness, even in complex gas mixtures. Finally, a 13.71 µm QCL is successfully coupled with a HCW, where optimal coupling conditions, beam quality, and loss are explored. The study confirms the efficient transmission of such wavelength through HCW with minimal loss and improved spatial beam quality

Wenn frühneuzeitliche Höfe, wie von Zeitgenossen immer wieder behauptet, nach Art einer Bühne funktionieren, dann liegt es nahe, höfisches Leben nach Praktiken des Sehens und Gesehen-Werdens, der Beobachtung, der Überwachung, des Zuschauens zu befragen. Während das höfische lch durch Prozesse formierenden Sehens entsteht, kann auch der Hof selbst, als Ort der Macht, als Produkt des koniglichen Blicks beschrieben werden. Der Band widmet sich den visuellen Praktiken an frühneuzeitlichen Höfen und untersucht die Formen und Funktionen sowie die Produktivität des Zuschauerblicks am elisabethanischen Hof. Im Zentrum der Analysen stehen Blickregim?es und Raumordnung während koniglicher "Progresses", visuelle Strategien höfischer Theaterproduktionen, die formative Wirkung des sozialen Sehens bei der Erziehung junger Männer an den Inns of Court sowie der Blick der Höflinge und Hofdamen auf die Königin beim Speisen und beim Tanz.

Arguments concerning patterns of sociocultural transformation at Pachacamac rely upon differential approaches to archaeological data. The “Deterministic Model” (DM) heavily favors environmental impacts (specifically tsunamis) as the prime mover in sociocultural transformations. The Local Chiefdom Model (LCM) sees Pachacamac as the Ychsma capital, home to a ruling elite that controlled the Lower and Middle Lurín Valley well before the arrival of the Inka. Finally, the Imperial Model (IM) argues that there was virtually no occupation prior to Tahuantinsuyu, attributing nearly all visible architecture to the Inkas. The DM excessively diminishes the role of human agency and is also inconsistent with Ychsma timing and development. The IM is too selective in its approach, overlooking total morphological pattern and architectural sequencing, methods for which Pachacamac is unusually well suited. This tends to provide support for the LCM. Finally, we suggest that bioarchaeology might provide alternative scenarios. We therefore aim to 1) delineate Andean archaeologists’ excessive enthusiasm for environmental/cultural narratives, 2) review Pachacamac’s monumental architecture in order to assess chronology and development and thus differentiate between the IM and the LCM, and 3) undertake a bioarchaeological assessment to determine whether tsunami events had any tangible human impact.

Nowadays, there is an increased trend in the construction of nearly zero energy buildings which can be also characterized as green buildings. Several studies confirm that wooden buildings fulfil these requirements. However, there is no detailed research related to the quality of the indoor environment in new wooden family houses. For this reason, this paper focuses on monitoring of the indoor environmental quality in a selected wooden family house. Short-term measurements are aimed at investigation of physical parameters (air temperature, relative humidity, air velocity and noise) and chemical factors such as concentrations of particulate matters and CO2. At the same time, environmental impacts were also assessed for impact categories such as: global warming potential (GWP), ozone depletion potential (ODP) acidification potential (AP), eutrophication potential (EP), photochemical ozone creation potential (POCP) ex-pressed as kilogram CO2eq, CFC11eq, SO2eq, PO43–eq and kilogram of C2H4eq within “Cradle to Grave” boundary by using the life cycle assessment (LCA) method. The main contribution of this study is demonstration that wooden build-ings have substantial share in the reduction of environmental impacts. So far, results indicate that the design of wooden houses correspond with the increasing demands of occupants in terms of environmental, social and energy performance.

Abstract The paper details the case history of a highly challenging, high deliverability exploratory gas well that was successfully drilled and completed in the frontier region. The 4,900 m well encountered multiple reservoirs during drilling with severe losses in the topmost prospective limestone reservoir formation. Subsequently, well was cased and Drill Stem Test (DST) was performed to test reservoir deliverability. During testing, severe leakages were encountered at the Surface Well Test (SWT) equipment due to high flow velocities, coupled with Loss Control Material (LCM) and formation cuttings flowback. This led to internal erosion in the equipment, resulting in frequent uncontrolled hydrocarbon release into the atmosphere, posing a high risk for personnel. Consequently, frequent shut-ins for maintenance were necessary. Steps taken to mitigate this issue are discussed and recommendations are proposed for future encounters. A systematic approach was adopted to offset the effects of erosion and consequential leakages. Points were identified which were prone to leakages, and successively, steps were taken to minimize bends. Non-intrusive thickness monitoring was carried out regularly to detect reduction(s) in the pipe schedule preemptively and take appropriate measures. Erosional velocities were computed for different pipe sections and sufficient back pressure was applied to reduce flow velocity. Other measures such as reducing flowing times at higher chokes and acid stimulation were also carried out to minimize the impact of, and dissolve, the particles eroding the equipment. Significant improvements were observed after taking preventive measures – Non-Productive Time (NPT) was reduced, and the remaining job was carried out safely without any impact on the personnel, equipment, environment and the Company reputation. Accuracy of the collected data also improved, as particles had inadvertent effects on flow measurements. An extensive study was carried out followed by on site actions to reduce the erosional impacts on a high pressure, high deliverability gas well. Important conclusions were drawn. Safe practices were developed to avoid future occurrences in high volume wells. A combination of steps such as re-arrangement of SWT setup to minimize bends, monitoring pipeline thickness using ultrasonic thickness meter, minimizing flow duration at high chokes, calculating downstream pressures required to limit erosion and applying back pressure, and performing acid stimulation can all help future operations to be carried out safely without any untoward downtime. In addition, dissolvable / degradable LCM could be opted in future wells, and wellbore hydraulics could be further studied to ensure optimum hole cleaning for effective cuttings removal.