698 research outputs found
Pressure measurement by Piezo-electric transducers in reciprocating combustion engines
The properties, use and construction of quartz Piezo electric transducers are briefly described. The dynamic calibration of quartz pressure transducers have been investigated using a Balanced-Disc pressure pick-up as a standard. The temperature effect on the static and dynamic output of these transducers has also been examined. Various types of engine indicators and their limitations are discussed. Piezo-electric pressure transducers and strain gauges were used for constructing an inertia-free pressure-volume indicator to produce a P-V diagram on an oscilloscope screen from which the trace was recorded. This included a simple and accurate method for obtaining top-dead-centre on pressure-time records. Some aspects of diesel combustion were considered using P-T diagrams from a variable compression Lister F.R.I diesel engine running at different loads and compression ratios. The effect of the shape of transducer passage on the accuracy of P-T diagrams is observed. Volumetric efficiency was measured using a crystal pressure transducer. The assumptions of this method was checked by comparison with the volumetric efficiency obtained by. two other established methods
Effect of vibration on condensation heat transfer coefficient
The project deals with an investigation into the effect of vibration on condensation heat transfer. Saturated steam was condensed on a horizontal stainless steel tube which was transversely vibrated in the plane of the gravitational field. The work involved the design, instrumentation and development of a test condenser which employed a reciprocating mode of vibration and was capable of operating at different amplitudes and frequencies. An electric method employing a constant current to measure the condenser tube temperature was explained. The experimental results showed improvements in the heat transfer coefficient with vibration, over its value with no vibration. Empirical correlation of the experimental data under vibrational conditions was established. Results for the static condenser tests were correlated with Nusselts classical theory of condensation. Visual observations of the condensate orientation and drainage under vibrational conditions was reported
Percutaneous Interventional Radiology-Operated Endoscopy for Foreign Body Removal
Image-guided retrieval of endovascular devices such as inferior vena cava filters, guidewires, and stents is well reported, though there is a paucity of published reports on biliary, genitourinary, or gastrointestinal foreign body retrieval utilizing percutaneous endoscopy, particularly when it is performed solely by interventional radiologists. In cases of failed traditional endoscopic techniques or to evade more invasive surgical options, percutaneous endoscopy can be an adjunctive tool employed by interventional radiologists to extract foreign bodies. In this article, clinical evaluation, perioperative management, and procedural techniques for biliary, genitourinary, and gastrointestinal endoscopy for foreign body retrieval are reviewed
3D BEM-based cooling-channel shape optimization for injection moulding processes
International audienceToday, around 30 % of manufactured plastic goods rely on injection moulding. The cooling time can represents more than 70 % of the injection cycle. Moreover, in order to avoid defects in the manufactured plastic parts, the temperature in the mould must be homogeneous. We propose in this paper a practical methodology to optimize both the position and the shape of the cooling channels in 3D injection moulding processes. For the evaluation of the temperature required both by the objective and the constraint functions, we must solve 3D heat-transfer problems via numerical simulation. We solve the heat-transfer problem using Boundary Element Method (BEM). This yields a reduction of the dimension of the computational space from 3D to 2D,avoiding full 3D remeshing: only the surface of the cooling channels needs to be remeshed at each evaluation required by the optimization algorithm. We propose a general optimization model that attempts at minimizing the desired overall low temperature of the plastic-part surface subject to constraints imposing homogeneity of the temperature. Encouraging preliminary results on two semi-industrial plastic parts show that our optimization methodology is viable
Assessment of Commonly Used Pesticides in the Ground Water of the Shallow Aquifer Systems in Jericho and Jeftlik areas/ Lower Jordan Valley, Occupied Palestinian Territories
One of the most important pollutants that may reach the groundwater through agricultural return flow combined with abuse and ignorance is pesticides. This study focuses on the examination of the concentration of three pesticides: Abamectin, Imidacloprid, and ß-Cyfluthrin, all of which have been used in large quantities in the Lower Jordan Valley (LJV) for the last three decades. Twenty five groundwater samples were collected from water boreholes where water is abstracted from two phreatic aquifer systems which are the Plio-Plistocene aquifer system in Jericho and Lower Al Jeftlik areas and the Eocene carbonate aquifer system in the Middle of Al Jeftlik. The depth of the boreholes in both aquifer system ranges between 80 and 120 m. Water samples were analyzed for Abamectin, Imidacloprid, and ß-Cyfluthrin using the HPLC-UV method. These samples represent two main agricultural locations (Jericho, and the Al Jeftlik). Of the 25 wells sampled, Abamectin was detected in 11 wells in concentrations ranging between 1.24 ppb and 81.71ppb. Imidacloprid was detected in 24 wells in concentrations ranging between 1.60ppb and 325.0ppb. Finally, ß-Cyfluthrin was detected in 7 wells in concentrations ranging between 1.10 and 24.46ppb. Aquifer lithology, groundwater flow directions, type of agricultural activity are major factors in controlling pesticide concentrations in groundwater. The highest values were measured where the aquifer consists of gravel and sand sediments, combined with intensive agricultural activities, followed by sand-silt aquifer. The lowest concentrations were found in boreholes where carbonate aquifer is the main source of water which indicates that other source of water flow into the system. The results of this study demonstrate that these pesticides are used heavily and in an improper way in the lower Jordan Valley, increasing the risk of adverse environmental and public health effects. Much attention should be given to addressing the potential problem of environmental and groundwater contamination by these pesticides.This study was funded through BARD-project /USDA
POSSIBLE PROTECTIVE ROLE OF SODIUM SALICYLATE NANOEMULSION AND GINGER ON CISPLATIN‑INDUCED HEPATOTOXICITY IN RATS (BIOCHEMICAL AND HISTOPATHOLOGICAL STUDY)
Objective: To describe the preparation and characterization of nanoemulsion of sodium salicylate loaded butane tetracarboxylic acid (Bt-Sc-NPs). It also investigates the possible protective effects of Bt-Sc-NPs and\or medicinal plant ginger to evaluate the changes of liver functions, oxidative stress and histopathological investigations against cisplatin-induced hepatotoxicity.
Methods: Serum was used to determine alanine aminotransferase (ALT), aspartate aminotransferase (AST), δ-glutamyl transferase (δGT), serum human laminin (LN) and tissue inhibitors of metalloproteinase1 (TIMP1). Liver tissue samples collected from the rats were used for the measurement of malondialdehyde (MDA), nitric oxide (NO) and paraoxonase 1 (PON1).
Results: The beneficial effects of Bt-Sc-NPs with its anti-inflammatory effect and the medicinal ginger with its antioxidant effect were observed. Injection of rats with cisplatin significantly increased serum ALT, AST, ɤGT, TIMP1 and LN. It also increased cisplatin-induced oxidative stress by a significant elevation in liver MDA, NO content; however, a significant decrease of PON1 content. While protection with Bt-Sc-NPs or ginger significantly improved these parameters. In addition, combination of both Bt-Sc-NPs and ginger significantly induced a decrease in serum ALT, AST, ɤGT, TIMP1 and LN. It also reduced cisplatin-induced oxidative stress by the significant reduction in liver MDA, NO content and elevation of PON1 content much more than protection with Bt-Sc-NPs or ginger alone.
Conclusion: Bt-Sc-NPs were synthesized using nanoemulsion with the help of homogenization and ultra-sonication waves. Combination with both of Bt-Sc-NPs and ginger showed a hepatoprotective role in ameliorating cisplatin‑induced hepatotoxicity due to their anti-inflammatory and antioxidant effects
Biological therapy of strontium-substituted bioglass for soft tissue wound-healing: Responses to oxidative stress in ovariectomised rats.
The authors declare that they have no conflicts of interest concerning this article.International audienceNew synthetic biomaterials are constantly being developed for wound repair and regeneration. Bioactive glasses (BG) containing strontium have shown successful applications in tissue engineering account of their biocompatibility and the positive biological effects after implantation. This study aimed to assess whether BG-Sr was accepted by the host tissue and to characterize oxidative stress biomarker and antioxidant enzyme profiles during muscle and skin healing. Wistar rats were divided into five groups (six animals per group): the group (I) was used as negative control (T), after ovariectomy, groups II, III, IV and V were used respectively as positive control (OVX), implanted tissue with BG (OVX-BG), BG-Sr (OVX-BG-Sr) and presented empty defects (OVX-NI). Soft tissues surrounding biomaterials were used to estimate superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and malondialdehyde (MDA) concentration. Our results show that 60 days after operation, treatment of rats with BG-Sr significantly increased MDA concentration and caused an increase of SOD, CAT and GPx activities in both skin and muscular tissues. BG-Sr revealed maturation of myotubes followed a normal appearance of muscle regenerated with high density and mature capillary vessels. High wound recovery with complete re-epithelialization and regeneration of skin was observed. The results demonstrate that the protective action against reactive oxygen species (ROS) was clearly observed in soft tissue surrounding BG-Sr. Moreover, the potential use of BG-Sr rapidly restores the wound skin and muscle structural and functional properties. The BG advantages such as ion release might make BG-Sr an effective biomaterial choice for antioxidative activity
The Cost-Effectiveness of Hepatitis C Virus Screening Strategies among Recently Arrived Migrants in the Netherlands
OBJECTIVE: We aimed to assess the cost-effectiveness of hepatitis C virus (HCV) screening strategies among recently arrived migrants in the Netherlands. METHODS: A Markov model was used to estimate the health effects and costs of HCV screening from the healthcare perspective. A cohort of 50,000 recently arrived migrants was used. In this cohort, three HCV screening strategies were evaluated: (i) no screening, (ii) screening of migrants from HCV-endemic countries and (iii) screening of all migrants. RESULTS: Strategy (ii) screening of migrants from HCV-endemic countries compared to strategy (i) no screening, yielded an incremental cost-effectiveness ratio (ICER) of €971 per quality-adjusted life-years (QALYs) gained. Strategy (iii) screening of all migrants compared with strategy (ii) screening of migrants from HCV-endemic countries yielded an ICER of €1005 per QALY gained. The budget impact of strategy (ii) screening of migrants from HCV-endemic countries and strategy (iii) screening of all migrants was €13,752,039 and €20,786,683, respectively. CONCLUSION: HCV screening is cost-effective. However, the budget impact may have a strong influence on decision making
Cost-effectiveness of screening smokers and ex-smokers for lung cancer in the Netherlands in different age groups
OBJECTIVE: We aimed to assess the cost-effectiveness of screening smokers and ex-smokers for lung cancer in the Netherlands. METHODS: A Markov model was used to evaluate the health effects and costs of lung cancer screening from the healthcare perspective. The effects and costs of ten screening scenarios with different start and stop ages of screening were examined across a lifetime horizon in a cohort of 100,000 smokers and ex- smokers 50 years and older. RESULTS: The incremental cost-effectiveness ratios (ICERs) of screening smokers and ex-smokers aged 50-60 years, 50-70 years, and 50 years and older are below the cost-effectiveness threshold of € 20,000 per quality adjusted life year (QALY) gained. Screening 50-60-year-old smokers and ex-smokers was the most cost-effective scenario with an ICER of € 14,094 per QALY gained. However, screening smokers and ex-smokers 50 years and older yielded the highest QALYs and resulted in an ICER of € 16,594 per QALY, which is below the threshold of € 20,000 per QALY. All screening scenarios compared to no screening resulted in CERs between the € 14,000 and € 16,000 per QALY gained. The efficiency frontier showed that screening smokers and ex-smokers in the age groups 70 years and older, 60-70 years, 60 years and older are excluded by extended dominance by no screening, screening smokers and ex-smokers aged 50-60 years and 50-70 years. CONCLUSION: This study showed that lung cancer screening is cost-effective in the Netherlands
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