Study on nitrogen barrier protection of an airend oil-free compressor bearings in H2 compression

The oil free compressors were specially designed for air compression. The National Research and Development Institute for Gas Turbines COMOTI gained a great deal of experience in producing/designing certified oil injection screw compressors for the natural gas field and for several years it has been focusing its research on the use of “dry” (oil-free) compressors in natural gas compression and more recently in hydrogen compression. Working with an explosive gas, one of an idea was to use a nitrogen barrier in oil bearing sealing, which are open source of gases in the atmosphere for such compressors. Worldwide, on-site nitrogen generators have been developed for a purity range of 95…99.5%, and that nitrogen can be supplied in any environment conditions. The present paper will address nitrogen flow with low percentage of oxygen for bearing sealing at the working pressure, the nitrogen consumption, ideas for H2 re-injection and the influence over the global efficiency of the process. Due to the Energy Strategy worldwide, and the studies regarding production, transport and storage of hydrogen in natural gas network, COMOTI has involved researches in developing such possibilities and to express a point of view in existing research in the newly created industry.

New technique for removal of perfluorocarbon liquid related sticky silicone oil and literature review

AIM: To investigate the safety and efficacy of sticky silicone oil (SSO) removal using a 22-gauge vein detained needle and inner limiting membrane (ILM) wrap-and-peel technique. METHODS: This retrospective consecutive case series reviewed the records of patients with a history of retinal detachment who had received silicone oil and perfluorocarbon liquid (PFCL) as intraocular tamponades. Patients were included in the analysis if they exhibited SSO remnants during silicone oil removal. The aspiration of most of the SSO remnants was performed by a 22-gauge vein detained needle. The small amounts of droplets adhered to the macula and epi-macular membrane were subsequently removed by the ILM warp-and-peel technique. The anatomical and functional outcomes, and postoperative complications were recorded. In vitro experiments were performed to simulate the formation of SSO remnants in four groups. RESULTS: Of 711 patients who underwent silicone oil removal during the study period, 9 patients exhibited SSO remnants and underwent follow-up for at least 3mo. Seven eyes (78%) underwent the ILM wrap-and-peel technique to completely remove small droplets of SSO that were glued to the macula and epi-macular membrane. No obvious complications occurred. Postoperative optical coherence tomography revealed normal retinal structure in all patients. In vitro analyses showed that balanced salt solution and prolonged vibration (for 1wk) had the strongest effects on silicone oil and PFCL compound opacities. CONCLUSION: SSO remnants could be removed in an intact manner and without complications, using a vein detained needle-assisted and ILM wrap-and-peel technique. The findings suggest that PFCL and infusion fluid should be completely removed before silicone oil injection to prevent SSO formation.

Human amniotic membrane for failed macular hole. A case of initial unsuccessful outcome that resolved after amniotic membrane exchange

Introduction We described a case of initial unsuccessful outcome of failed macular hole treated with amniotic membrane, that resolved after amniotic membrane exchange and silicone oil injection. Case Description a woman affected by a high myopic macular hole that had failed to close after multiple surgeries, had been treated using an amniotic membrane graft and 20% sulfur hexafluoride but, after the gas reabsorption, the macular hole was still open, and the amniotic membrane. A second surgery with a second amniotic membrane patch and silicone oil was carried out. Two weeks after the procedure the macular hole closed, and the final visual acuity improved from 20/400 to 20/100. Conclusions In this case, a second surgery, using a new amniotic membrane graft and a longer-lasting endotamponade, closed the hole and improved the visual acuity.

A Comprehensive Project of Thermal, Gas and Chemical EOR Method Application for Bazhenov Shale Formation

The article describes the development aimed at a comprehensive study for enhanced oil recovery methods (EOR) of the Bazhenov shale oil formation. Potentially effective technologies for low-permeable reservoirs are under consideration: injection of associated petroleum gas in the mode of miscible displacement to recover light oil; injection of the surfactants water solutions, to separate sorbed hydrocarbons from the rock and change core wettability; and heating technologies to convert solid hydrocarbons into liquid and gaseous, and recover. The project explore potentially effective EOR technologies and their influence on the various types of hydrocarbons of the shale Bazhenov formation: mobile oil in closed pores, sorbed and solid (kerogen) hydrocarbons. Experimental studies were carried out: the selection of the gases composition, the selection of surfactant compositions, the study of the possibility of thermal exposure by over-heated water injection. The project is currently at the stage of determining the effectiveness of each method, selecting a technology for specific field conditions and identifying which hydrocarbon resources each method is aimed at extracting.

Endophthalmitis and Retinal Detachment after Ocular Injury by Animal Inoculation Needle

Purpose: To report a case of endophthalmitis and retinal detachment after injury caused by an animal inoculation needle. Case summary: A 39-year-old man received an injury to his left eye with an animal inoculation needle while vaccinating a pig came to the hospital due to decreased visual acuity. At initial presentation, the best-corrected visual acuity in the left eye was “counting fingers,” and slit lamp examination revealed corneal lacerations, anterior capsule rupture, and traumatic cataract. Ultrasonography showed no specific findings in the vitreous and retina. Primary corneal suture, phacoemulsification, anterior vitrectomy due to rupture of the posterior capsule and vitreous prolapse, intraocular lens implantation, and intravitreal antibiotic injection were performed. On day 1 postoperatively, vitrectomy, anterior chamber irrigation, intravitreal antibiotic injection, and silicone oil injection were performed as signs of endophthalmitis, such as hypopyon and retinal tear, and focal retinal detachment were observed during surgery. Silicone oil removal was performed 7 months after the operation and the best-corrected visual acuity was 0.6. There has been no recurrence during follow-up. Conclusions: This is the first report in Korea of ocular injury caused by an animal inoculation needle. If the fundus is not observed in such injuries, there is a possibility of endophthalmitis and retinal detachment and early vitrectomy should be considered.

Hemorrhagic Retinal Macrocyst with Retinal Detachment

Purpose: To report a satisfactory clinical outcome of hemorrhagic retinal macrocyst with retinal detachment after pars plana vitrectomy and silicone oil injection. Case summary: A 33-year-old man visited our clinic with a 1-week history of visual disturbance in his left eye. His ocular and medical history were unremarkable, and best-corrected visual acuity (BCVA) in the left eye was 20/40. Fundoscopic examination of the left eye showed a hemorrhagic retinal macrocyst that was well-demarcated, semi-transparent, dome-shaped, and larger than 8 disc diameters at the superonasal location, with macular-off retinal detachment. B-scan ultrasonography also confirmed the presence of an intra-retinal cystic lesion with internal mobile echogenic signals representing blood. The patient underwent 23-gauge pars plana vitrectomy, barrier laser photocoagulation around the retinal tear and boundary of the cyst, and silicone oil injection, without any other additional procedures for the hemorrhagic retinal macrocyst. After the surgery, the patient stayed in the face down position for two weeks. Three months postoperatively, a completely collapsed hemorrhagic retinal macrocyst with successful retinal reattachment was observed. Six months later, the BCVA in the left eye had improved to 20/30. One year later, even after silicon oil removal, the collapsed hemorrhagic retinal macrocyst and reattached retina remained stable.Conclusions: A hemorrhagic retinal macrocyst with retinal detachment was successfully treated with pars plana vitrectomy and silicone oil tamponade.

Experimental study of systems and oils for direct cooling of electrical machine

This study presents a test campaign carried out at IFPEN aimed at understanding and characterizing the thermal behaviour of electric motors incorporating direct oil cooling. Several cooling systems and oils are evaluated at different operating points and the effect of parameter variations is investigated. Experimentations are defined and performed to understand and quantify the impact of different oils and direct cooling systems on the performances of the electrical machine. The test results make it possible to verify and quantify the gain on the thermal behaviour obtained by adding an oil injection system directly to the active parts of the machine in addition of an indirect water jacket cooling. This gain is observed for a representative set of operating points and oil injection parameters. The impact of physico-chemical properties of oils on direct cooling performance is assessed by comparison of several oils. The viscous friction losses are also identified. The results presented include a repeatability and reproducibility study for speed values up to 14 krpm and continuous powers up to 60 kW.

Medical management of silicone oil associated acute postoperative ocular inflammation

We report a case of a 57-year-old man, who underwent right eye silicone oil injection as a part of his surgical treatment for rhegmatogenous retinal detachment. Following this, on the first postoperative day, he developed acute postoperative intraocular inflammation. There was circumciliary congestion, diffuse corneal oedema, anterior chamber (AC) reaction, hypopyon and a pupillary membrane. The AC had not been entered during the surgery. No patients, who had been operated on the same day, or with the materials having the same batch number, developed similar reactions. We started the patient on hourly topical steroids and cycloplegics after which the patient’s condition showed gradual improvement. At the 2 weeks follow-up appointment, his pupillary membrane had completely contracted and the AC was quiet. This case highlights a clinical picture of acute postoperative silicone oil-induced ocular inflammation, which was resolved through medical management.