The influence of power and frequency on the filamentary behavior of a flowing DBD-application to the splitting of CO2

In this experimental study, a flowing dielectric barrier discharge operating at atmospheric pressure is used for the splitting of CO2 into O2 and CO. The influence of the applied frequency and plasma power on the microdischarge properties is investigated to understand their role on the CO2 conversion. Electrical measurements are carried out to explain the conversion trends and to characterize the microdischarges through their number, their lifetime, their intensity and the induced electrical charge. Their influence on the gas and electrode temperatures is also evidenced through optical emission spectroscopy and infrared imaging. It is shown that, in our configuration, the conversion depends mostly on the charge delivered in the plasma and not on the effective plasma voltage when the applied power is modified. Similarly, at constant total current, a better conversion is observed at low frequencies, where a less filamentary discharge regime with a higher effective plasma voltage than that at a higher frequency is obtained

Designing and analyzing park sensor system for efficient and sustainable car park area management

Many problems have been seen in cities because of increasing vehicle density. One of these problems is vehicle density in parking lots. People look for empty parking areas and they spend too much time. While people look for empty parking areas, CO2 (carbon dioxide) emission and energy consumption increase due to density in parking lots. We worked to solve these problems by doing Magnetic Car Park Sensor. Magnetic Car Park Sensor is the system which detects cars in car parks. After cars detected with the system, the system sends information to center server and we can see information data in the system interface. The system helps people to find empty parking lots. As people find empty car park areas fastly, energy consumption and CO2 emission are decreased significantly

Reproducibility of endometrial intraepithelial neoplasia diagnosis is good, but influenced by the diagnostic style of pathologists

Endometrial intraepithelial neoplasia (EIN) applies specific diagnostic criteria to designate a monoclonal endometrial preinvasive glandular proliferation known from previous studies to confer a 45-fold increased risk for endometrial cancer. In this international study we estimate accuracy and precision of EIN diagnosis among 20 reviewing pathologists in different practice environments, and with differing levels of experience and training. Sixty-two endometrial biopsies diagnosed as benign, EIN, or adenocarcinoma by consensus of two expert subspecialty pathologists were used as a reference comparison to assess diagnostic accuracy of 20 reviewing pathologists. Interobserver reproducibility among the 20 reviewers provided a measure of diagnostic precision. Before evaluating cases, observers were self-trained by reviewing published textbook and/or online EIN diagnostic guidelines. Demographics of the reviewing pathologists, and their impressions regarding implementation of EIN terminology were recorded. Seventy-nine percent of the 20 reviewing pathologists' diagnoses were exactly concordant with the expert consensus (accuracy). The interobserver weighted kappa values of 3-class EIN scheme (benign, EIN, carcinoma) diagnoses between expert consensus and each of reviewing pathologists averaged 0.72 (reproducibility, or precision). Reviewing pathologists demonstrated one of three diagnostic styles, which varied in the repertoire of diagnoses commonly used, and their nonrandom response to potentially confounding diagnostic features such as endometrial polyp, altered differentiation, background hormonal effects, and technically poor preparations. EIN diagnostic strategies can be learned and implemented from standard teaching materials with a high degree of reproducibility, but is impacted by the personal diagnostic style of each pathologist in responding to potential diagnostic confounders

CO2 splitting in a dielectric barrier discharge plasma: understanding of physical and chemical aspects

Le dioxyde de carbone, principal gaz à effet de serre lié aux activités humaines, est considéré comme l’un des gaz les plus problématiques pour notre environnement ces dernières années, principalement à cause du réchauffement climatique qu’il engendre. C’est pour cette raison que l’augmentation de sa teneur dans l’atmosphère nous concerne tous quant aux conséquences futures pour notre planète. Afin de limiter l’émission de CO2, sa conversion en composés à valeur ajoutée présente un grand intérêt et est possible notamment via des procédés plasmas. Plus particulièrement, les décharges à barrière diélectrique (DBD) sont utilisées depuis quelques années pour générer des plasmas froids opérant à pression atmosphérique, principalement pour des applications en traitement de surface, mais également pour le traitement d’effluents gazeux.Lors de cette thèse, nous nous sommes focalisés sur le processus de dissociation du CO2 en CO et O2 via un réacteur DBD à flux continu et avons analysé sa conversion et son efficacité énergétique via différentes études. Celles-ci ont été réalisées grâce à plusieurs méthodes de diagnostic, comme par exemple la spectrométrie de masse utilisée pour déterminer la conversion et l’efficacité du processus, la spectroscopie d’émission optique, l’oscilloscope pour une caractérisation électrique, etc. afin d’avoir une meilleure compréhension du comportement des décharges CO2.Dans un premier temps, nous avons réalisé une étude détaillée d’un plasma CO2 pur où nous avons fait varier différents paramètres, tels que le temps de résidence, la fréquence, la puissance, la pulsation de la haute tension et l’épaisseur et la nature du diélectrique. Le CO2 donne lieu généralement à une décharge filamentaire, consistant en de nombreuses microdécharges réparties au niveau de la zone du plasma. Celles-ci constituent la principale source de réactivité dans une DBD. Un aperçu détaillé de l’aspect physique de ces microdécharges a été réalisé grâce à la caractérisation électrique, permettant de mieux comprendre les propriétés électriques de la décharge et des microdécharges. En effet, nous avons pu déterminer l’importance de la tension présente au niveau du plasma, de l’intensité du courant plasma, du nombre de microdécharges et de leur temps de vie sur l’efficacité du processus de dissociation de CO2.Ensuite, nous avons conclu ce travail avec des études combinant le CO2 en phase plasma avec de l’eau ou du méthane afin de produire des molécules à valeur ajoutée telles que les syngas (CO et H2), mais aussi des hydrocarbures (C2H6, C2H4, C2H2 et CH2O) dans le cas de l’ajout du méthane. A travers ces études, nous avons obtenu une meilleure connaissance de la chimie et de la physique qui ont lieu dans ce type de plasma.Carbon dioxide appears as one of the most problematic gases for the environment, mostly because it is responsible for global warming. This is why its increasing concentration into the atmosphere, mainly due to anthropogenic activities, is a real concern for planet Earth. In order to prevent the release of large amounts of CO2, its conversion into value-added products is of great interest. In this context, plasma-based treatments using dielectric barrier discharges (DBDs) are nowadays more and more used for the conversion of this gas. In this thesis, we investigated the CO2 splitting process into CO and O2 via a flowing cylindrical DBD and we studied its conversion and energy efficiency by means of several diagnostic methods, such as mass spectrometry to determine the conversion and energy efficiency of the process, optical emission spectroscopy for gas temperature measurements, and an oscilloscope for electrical characterization, in order to obtain a better understanding of the CO2 discharge itself.First, we focused on an extensive experimental study of a pure CO2 plasma where different parameters were varied, such as the gas residence time, the operating frequency, the applied power, the pulsation of the AC signal, the thickness and the nature of the dielectric. CO2 discharges typically exhibit a filamentary behavior, consisting of many microdischarges, which act as the main source of reactivity in a DBD. A detailed insight in the physical aspects was achieved by means of an in-depth electrical characterization, allowing more insight in the electrical properties of the discharge and more specifically in the microdischarges, which are spread out throughout the active zone of the plasma. It was found throughout this work that the plasma voltage, which reflects the electric field and thus determines how the charged particles are accelerated, the plasma current, which reflects the electron density, but also the number of microdischarges and their average lifetime, play an important role in the efficiency of the CO2 dissociation process. It was revealed that the microdischarge number is important as it represents the repartition of the locations of reactivity. Indeed, as the microfilaments are more spread out in the same discharge volume, the probability for the CO2 molecules to pass through the reactor and interact with at least one microdischarge filament becomes more important at a larger number of microfilaments.The second part of the thesis was dedicated to discharges combining CO2 and H2O or CH4, both being hydrogen source molecules. The combined CO2/H2O or CO2/CH4 conversion allows forming value-added products like syngas (CO and H2), but also hydrocarbons (C2H6, C2H4, C2H2 and CH2O), at least in the presence of methane. Throughout this study, we tried to obtain a better knowledge of the chemistry and physic behind these conversion processes.Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe

An evaluation of factors affecting pain during transrectal ultrasonographic prostate biopsy: a real-life scenario in a retrospective cohort study

Background Periprostatic infiltration anesthesia (PPIA) and intrarectal topical anesthesia (IRTA) are recommended methods to control pain in transrectal ultrasonographic prostate biopsy (TRUS-Bx). This study evaluates the factors affecting pain during TRUS-Bx, considering the pathologies involved in anorectal pain etiology and comparing the effectiveness of local anesthesia techniques in providing patient comfort. Material and Methods We retrospectively evaluated 477 consecutive patients with TRUS-Bx for elevated Prostate Specific Antigen (PSA), abnormal rectal examination findings, or both. Patients were grouped as local anesthesia methods for pain control during TRUS-Bx. Both groups were compared in terms of age, body mass index, clinical T stage, PSA, prostate volume, number of biopsy cores, type of anesthesia, previous biopsy history, and presence of prostate cancer. We used a visual analog pain scale (VAS) to evaluate the patient’s pain status; pre-procedure (VAS-0), during probe insertion (VAS-I), administration of anesthetic (VAS-A), and simultaneous with the biopsy procedure itself (VAS-Bx). For PPIA and IRTA, 4 ml lidocaine 20 mg/ml injection and 5 g 5% prilocaine-5% lidocaine cream was used, respectively. Results The PPIA was used 74.2% (n = 354) and IRTA was used for 25.8% (n = 123) patients. VAS-0, VAS-I, and VAS-A scores are similar between groups. VAS-Bx was significantly higher in the IRTA than in the PPIA (3.37 ± 0.18 vs. 2.36 ± 0.12 p > 0.001). Clinical T stage (OR: 0.59), number of biopsy cores (OR: 1.80), and type of anesthesia application (OR: 2.65) were independent variables on TRUS-Bx for pain. Conclusion Three factors play roles as independent variables associated with the pain in TRUS-Bx; abnormal rectal examination findings, collection of more than twelve core samples during the biopsy, and the type of anesthesia used. Compared with PPIA, IRTA does not improve pain related to probe insertion, and using IRTA results in higher pain scores for biopsy-related pain. Thus, we recommend a PPIA to lower biopsy-related pain

Angioleiomyoma of the scrotal wall

Angioleiomyoma of the scrotum is a rare benign lesion which can mimic a paratesticular tumor. Any solid mass within the scrotum is considered malignant until proven otherwise. Here, we present a case of an angioleiomyoma of the scrotum in a 33-year-old male who presented with painful scrotal mass. Scrotal ultrasonography demonstrated a solid mass in the scrotum, and surgical excision was carried out. Pathologic examination revealed that the tumor was angioleiomyoma

How do the barrier thickness and dielectric material influence the filamentary mode and <tex>CO_{2}$</tex> conversion in a flowing DBD?

Dielectric barrier discharges (DBDs) are commonly used to generate cold plasmas at atmospheric pressure. Whatever their configuration (tubular or planar), the presence of a dielectric barrier is mandatory to prevent too much charge build up in the plasma and the formation of a thermal arc. In this article, the role of the barrier thickness (2.0, 2.4 and 2.8 mm) and of the kind of dielectric material (alumina, mullite, pyrex, quartz) is investigated on the filamentary behavior in the plasma and on the CO2 conversion in a tubular flowing DBD, by means of mass spectrometry measurements correlated with electrical characterization and IR imaging. Increasing the barrier thickness decreases the capacitance, while preserving the electrical charge. As a result, the voltage over the dielectric increases and a larger number of microdischarges is generated, which enhances the CO2 conversion. Furthermore, changing the dielectric material of the barrier, while keeping the same geometry and dimensions, also affects the CO2 conversion. The highest CO2 conversion and energy efficiency are obtained for quartz and alumina, thus not following the trend of the relative permittivity. From the electrical characterization, we clearly demonstrate that the most important parameters are the somewhat higher effective plasma voltage (yielding a somewhat higher electric field and electron energy in the plasma) for quartz, as well as the higher plasma current (and thus larger electron density) and the larger number of microdischarge filaments (mainly for alumina, but also for quartz). The latter could be correlated to the higher surface roughness for alumina and to the higher voltage over the dielectric for quartz