Renewable energy allocation based on maximum flow modelling within a microgrid

This paper designs an energy allocation scheme based on maximum flow modeling for a microgrid containing renewable energy generators and consumer facilities. Basically, the flow graph consists of a set of nodes representing consumers or generators as well as a set of weighted links representing the amount of energy generation, consumer-side demand, and transmission cable capacity. The main idea lies in that a special node is added to account for the interaction with the main grid and that two-pass allocation is executed. In the first pass, the maximum flow solver decides the amount of the insufficiency and thus how much to purchase from the main grid. The second pass runs the flow solver again to fill the energy lack and calculates the surplus of renewable energy generation. The performance measurement result obtained from a prototype implementation shows that the generated energy is stably distributed over multiple consumers until the energy generation reaches the maximum link capacity.

Selecting the Appropriate First-Line Strategy Based on Hyperdense Vessel Sign in Acute Ischemic Stroke Increases First Pass Recanalization: A Tertiary Center Experience

Background: The data pertaining to selecting an optimal first-line strategy (stent retriever [SR] vs. contact aspiration [CA]) based on noncontrast computed tomography (NCCT) in cases of acute ischemic stroke consequent to large vessel occlusion (LVO) is lacking. Aims: This article studies the influence of hyperdense vessel sign (HVS) in selecting optimal first-line strategy, with intention of increasing first-pass recanalization (FPR). Methods: Upfront approach at our center is SR technique with rescue therapy (CA) adoption consequent to three failed SR attempts to achieve successful recanalization. Data of patients with acute LVO who underwent mechanical thrombectomy from June 2017 to May 2020 was retrospectively analyzed. Patients were classified into HVS (+) and HVS (–) cohort. Rate of successful recanalization (first pass, early, and final) and efficacy of rescue therapy was assessed between the two cohorts. Results: Of 52 patients included, 28 and 24 were assigned to the HVS (+) and HVS (–) cohort, respectively. FPR was observed in 50% of HVS (+) and 20.9% of HVS (–) (p = 0.029). Early recanalization was documented in 64.2% of HVS (+) and 37.5% of HVS (–) (p = 0.054). Rescue therapy need was higher in patients not demonstrating HVS (p = 0.062). Successful recanalization was achieved with rescue therapy in 50% of HVS (–) group. Conclusion: A higher FPR is achievable following individualized first-pass strategy (based on NCCT appearance of clot), instead of a generalized SR first-pass approach. This CT imaging-based strategy is a step closer to achieving primary angiographic goal of FPR.

Hardness and Microstructure Homogeneity of Pure Copper and Iron-Chromium Alloy Processed by Severe Plastic Deformation

Hardness and microstructure homogeneity of pure copper and iron-chromium alloy processed by severe plastic deformation (SPD) were investigated in grain refinement. Equal channel angular pressing (ECAP) is one of the well-known techniques of the SPD technique due to their up-scale ability and other methods. SPD was applied to pure copper and iron-chromium alloy at comparable temperatures up to four passes. The microstructure and microhardness were observed and measured in the transverse plane for each billet. The homogeneity observation was carried out from the sub-surface until in the middle of the billet. The result showed that the deformed structure appeared adequately after the first pass and had a higher hardness level. The first pass showed a higher inhomogeneity factor than the fourth pass due to the homogeneity microstructure. The hardness also showed homogeneous value along the transverse plane, and it was concluded that ECAP could achieve complete homogeneity in grain refinement

Thermodynamic Limitations and Exergy Analysis of Brackish Water Reverse Osmosis Desalination Process

The reverse osmosis (RO) process is one of the most popular membrane technologies for the generation of freshwater from seawater and brackish water resources. An industrial scale RO desalination consumes a considerable amount of energy due to the exergy destruction in several units of the process. To mitigate these limitations, several colleagues focused on delivering feasible options to resolve these issues. Most importantly, the intention was to specify the most units responsible for dissipating energy. However, in the literature, no research has been done on the analysis of exergy losses and thermodynamic limitations of the RO system of the Arab Potash Company (APC). Specifically, the RO system of the APC is designed as a medium-sized, multistage, multi pass spiral wound brackish water RO desalination plant with a capacity of 1200 m3/day. Therefore, this paper intends to fill this gap and critically investigate the distribution of exergy destruction by incorporating both physical and chemical exergies of several units and compartments of the RO system. To carry out this study, a sub-model of exergy analysis was collected from the open literature and embedded into the original RO model developed by the authors of this study. The simulation results explored the most sections that cause the highest energy destruction. Specifically, it is confirmed that the major exergy destruction happens in the product stream with 95.8% of the total exergy input. However, the lowest exergy destruction happens in the mixing location of permeate of the first pass of RO desalination system with 62.28% of the total exergy input.

Formulation and Evaluation of Mucoadhesive in-Situ Nasal Gel of Tapentadol Hydrochloride

Tapentadol Hydrochloride is a Tapentadol is a centrally acting analgesic. It has 33% bioavailability due to its first pass effect and hence possesses problems in the development of oral sustained release formulations. Mucoadhesive thermo reversible in-situ nasal gel of Tapentadol HCl was designed and developed to sustain its release due to the increased nasal residence time of the formulation. Poloxamer 407 (PF 127) was selected as it has excellent thermo sensitive gelling properties. HPMCK4M was added to impart mucoadhesive to the formulation, and PEG 400 was used to enhance the drug release. 32 Factorial designs were employed to assess the effect of concentration of HPMCK4M and PEG 400 on the performance of in-situ nasal gel systematically and to optimize the formulation. An optimized in-situ nasal gel was evaluated for appearance, pH, drug content, gelation temperature, mucoadhesive force, viscosity and ex-vivo permeability of drug through nasal mucosa of a goat. Additionally, this formulation was proved to be safe as histopathological studies revealed no deleterious effect on nasal mucosa of a goat after prolonged exposure of 21 days to the optimized formulation. Thus the release of Tapentadol Hydrochloride can be sustained if formulated in an in-situ nasal gel containing poloxamer 407 to achieve its prolonged action.

Experimental Evaluation of the Effectiveness of Aspiration-Based Techniques to Treat Different Types of Acute Thromboembolic Occlusions in the Femoropopliteal Vascular System Using an In Vitro Flow Model

Purpose In this in vitro study, the effectiveness and safety of four aspiration-based techniques for thrombectomy are evaluated for three types of thrombi in a flow model simulating the femoropopliteal segment. Material and Methods Red, white, and mixed thrombi were produced in a standardized manner and used to simulate occlusion of a superficial femoral artery using a pulsatile flow model. Four techniques were compared: aspiration alone, aspiration + stent retriever, exposing thrombus to laser by an excimer laser system and a laser catheter + aspiration, and aspiration + mechanical fragmentation by a separator. Rate of first-pass recanalization, embolic events, and number of embolized fragments > 1 mm were compared. Results Aspiration alone, stent retriever, laser, and separator differed in rates of first-pass recanalization (53.3%; 86.6%; 20%; and 100%) and embolic events (40%; 93.3%; 73.3%; and 60%). Number of embolized fragments was lowest with aspiration and higher with separator, laser, and stent retriever. Rates of first-pass-recanalization (75%; 75%; and 45%) and embolic events (65%; 60%; and 75%) differed for red, white, and mixed thrombi. The mixed thrombus caused the highest number of embolized fragments, which was particularly high using the stent retriever. Conclusion Additional use of mechanical techniques significantly enhances the effectiveness of thrombectomy but simultaneously provokes more embolism. Laser seems to negatively alter the structure of a thrombus and thus diminishes the effectiveness, while provoking embolism. All techniques had lowest effectiveness, but highest embolism with the mixed thrombus. This was particularly striking when a stent retriever was used with the mixed thrombus.

Aspiration thrombectomy using a novel 088 catheter and specialized delivery catheter

BackgroundWe describe the first-in-human experience using the Route 92 Medical Aspiration System to perform thrombectomy in the initial 45 consecutive stroke patients enrolled in the SUMMIT NZ trial. This aspiration system includes a specifically designed delivery catheter which enables delivery of 0.070 inch and 0.088 inch aspiration catheters.MethodsThe SUMMIT NZ trial is a prospective, multicenter, single-arm study with core lab imaging adjudication. Patients presenting with acute ischemic stroke from large vessel occlusion are eligible to enrol. The study has had three phases which transitioned from use of the 0.070 inch to the 0.088 inch catheter.ResultsVessel occlusions were located in the internal carotid artery (27%), M1 (60%) and M2 (13%). Median baseline National Institutes of Health Stroke Scale (NIHSS) was 16 (IQR 10). Across the three phases, the first-pass reperfusion rate of modified Thrombolysis In Cerebral Infarction (mTICI) ≥2b was 62% using the Route 92 Medical system; this rate was 29% in phase 1, 56% in phase 2, and 80% in phase 3. The first-pass reperfusion rate of mTICI ≥2c was 42% overall, 29% in phase 1, 33% in phase 2%, and 55% in phase 3. A final reperfusion rate of mTICI ≥2b was achieved in 96% of cases, with 36% of cases using adjunctive devices. Patients had an average improvement of 6.7 points in NIHSS from baseline at 24 hours, and at 90 days 48% were functionally independent (modified Rankin Scale 0–2).ConclusionsIn this early experience, the Route 92 Medical Aspiration System has been effective and safe. The system has design features that improve catheter deliverability and have the potential to increase first-pass reperfusion rates in aspiration thrombectomy.