A Review of Leak Detection Systems for Natural Gas Pipelines and Facilities

Pipelines facilities, used for the transportation of natural gas in large quantities to homes and industries, remain the best economic, most reliable and safest mode of transport of energy. Despite these numerous advantages, gas pipelines have been enmeshed in various accidents and thefts, nonetheless this could be reduced if properly maintained and pipelines can last indefinitely without leaks. Pipelines are susceptible to leakages and rupture accidents as a result of age, corrosion, material defects, operational errors or other reasons. Pipeline failures may be caused intentionally (e.g. vandalism) or unintentionally (e.g. device/material failure and corrosion), which may result into irreversible damages such as financial losses, human casualties, ecological disaster and extreme environmental pollution. Leakages in natural gas facilities and installations require three vital aspects, namely: Gas Leakage Prevention, Gas Leakage Detection and Gas Leakage Mitigation. Many Gas Leak Detection methods are used for pipeline integrity management and especially for minimizing gas leakage. The performance of these methods depends on the approaches, operational conditions and pipeline networks. Also, there are some essential requirements and guidelines which must be met before we can consider any leak detection system suitable for production solutions, including sensitivity, reliability, accuracy and robustness. The attempt of this study is to carry out a critical review of these models, to ascertain the best model(s) applicable to natural gas leak detection. Keywords: Gas Leak Detection System, Leak Location, Leak Size DOI: 10.7176/JETP/13-2-02 Publication date: April 30th 202

Data for analyzing drilling fluid ability to effectively achieve hole cleaning for high shear and low shear rates

Rheological models such as Bingham Plastic or Power law models depict fluid behavior with points of the rheological relation which correspond to higher shear rates, but these models are fairly easy to solve for their specific descriptive parameters. Lower rpm (and hence shear rate), could be used to improve the performance and understanding of drilling mud at the lower shear rates prevailing in the wellbore. These data can be utilized in validating these rheological models and the essence of Equivalent Circulating Density (ECD) calculation in analyzing pressure drop in annular hole cleaning

Comparative electrocardiographic effects of propofol-tramadol and propofol-ketamine anaesthesia in puppies

SummaryThe electrocardiographic and arrhythmogenic effects of ketamine or tramadol premedication on propofol induced anesthesia in puppies were investigated. Five healthy puppies were randomly assigned to either propofolketamine (PK) or propofol-tramadol (PT) treatment group. They were premedicated with 0.02mg/kg atropine sulphate, 0.25mg/kg chlorpromazine and sub-anesthetic dose (2.5mg/kg) of ketamine hydrochloride or 2mg/kg tramadol hydrochloride. Induction of anesthesia was achieved twenty minutes later with intravenous propofol (5mg/kg). A week was allowed between each protocol. The cardiac rate and ECG indices such as QT variability, QT width, and heart rate corrected QT interval (QTc), RR variability and T wave voltage were obtained in lead II electrocardiogram before and at 0, 5, 10, and 15minutes after propofol induction. While the heart rate, QT width and RR variability index during anesthesia was not significantly different from control values in PT group, the heart rate and T wave voltage was increased while the QT width and RR variability were decreased during anesthesia in the PK group. The main effect of anesthesia on the RR variability, T wave voltage and heart rate was also higher in the PK group. A significant (p<0.05) and positive correlation was also found between QT variability and RR variability in the PK group. This study showed that PK regime of anesthesia in puppies had a higher effect on the sympatho-excitatory system and consequently on the ventricular repolarization indices and should therefore be used with caution in puppies because of its arrythmogenic potentials.Keywords: Arrhythmia, canine pediatrics, ketamine, propofol, tramadol, ECG, anesthesiaRésumé Les effets électrocardiographiques et arythmogènes de la kétamine ou le tramadol prémédication sur l'anesthésie de propofol induit chez les chiots ont été étudiés. Cinq chiots sains ont été assignés au hasard à propofol-ketamine (PK) ou le groupe de traitement de propofol-tramadol (PT). Ils ont été premedicated avec le sulfate d'atropine de 0,02 mg/kg, la chlorpromazine 0,25 mg/kg et sous anesthésie dose (2,5 mg/kg) de chlorhydrate de kétamine ou 2 mg/kg de chlorhydrate de tramadol. Induction de l'anesthésie a été réalisée vingt minutes plus tard avec le propofol par voie intraveineuse (5mg/kg). Une semaine a été autorisée entre chaque protocole. La fréquence cardiaque et les indices de l'ECG telles que la variabilité de l'intervalle QT, QT width et fréquence cardiaque corrigé QT interval (QTc), variabilité RR et tension onde T ont été obtenus dans l'électrocardiogramme de plomb II avant et à 0, 5, 10 et 15 minutes après l'induction de propofol. Tandis que la fréquence cardiaque, la largeur de l'intervalle QT et la variabilité de la RR index pendant l'anesthésie n'était pas significativement différent de valeurs de contrôle dans le groupe PT, la fréquence cardiaque et tension onde T a augmenté alors que la largeur de l'intervalle QT et de la variabilité RR ont diminué pendant l'anesthésie de la pharmacocinétique groupe. Le principal effet de l'anesthésie sur la variabilité RR, la T vague tension et la fréquence cardiaque était également plus élevé dans le groupe de PK. Un objectif important (p<0,05) et positif aussi de corrélation entre la variabilité de l'intervalle QT et variabilité RR dans le groupe de PK. Cette étude a montré que le régime PK de l'anesthésie chez les chiots avait un effet plus élevé sur le système sympathico-excitatrice et par conséquent sur les indices de la repolarisation ventriculaire et doit donc être utilisé avec prudence chez les chiots en raison de son potentiel arrythmogenic. Mots clés: arythmie, pédiatrie canine, kétamine, propofol, tramadol, ECG, anesthésie. West Afr. J. Pharmacol. Drug Res. Vol.32 January – December 2017; 16-2