Optimization of a small-scale polygeneration system for a household in Turkey

With environmental concerns, alternative solutions for generating electricity while decreasing the consumption of fossil fuels have gained a great importance. Polygeneration is one of these solutions which is also capable to increase the technical performance of electricity generation. Polygeneration systems are available in large scale, medium scale and small scale. This study focuses on small scale polygeneration systems specifically for residential applications. Type and size of the components and the system’s operational strategy plays a significant role in polygeneration system design as these factors affect the system cost and also environmental impacts. This study aims to propose a guide for component selection, sizing and addressing a suitable operational strategy for a predefined system configuration. Decision making criteria is defined for component selection by a comprehensive literature review. Internal combustion engines, Stirling engines, micro gas turbines and fuel cells are investigated within these criteria. This provides the user an insight on component selection. When combined with factors such as market conditions, location and especially household demand profile, a selection can easily be made by the customer. For component sizing and operational strategy, a model has been implemented in Matlab. A baseline case model with a predefined system configuration and operational strategy was defined. The baseline case system includes a prime mover, a back-up auxiliary boiler, a vapor compression refrigeration chiller, a thermal energy storage and solar thermal collectors for the domestic hot water demand. The operational strategy is defined as thermal load following. For the case study, this model was altered for different cases with alterations on the operational strategy and the system configuration in order to identify the optimal solution for the user where the total annual cost is minimized while satisfying all kinds of end-use demands of a single-family household in Ankara, Turkey. The results also give insights on the effect of having solar thermal collectors and a thermal energy storage coupled with a CHP unit on the overall system

Two cases of choroidal osteoma

Choroidal osteoma is a benign, bony tumour of the choroid, which affects otherwise healthy females in the second or third decades of their lives. The tumour is frequently asymptomatic, but rarely can cause neovascularisation of the choroid and be sight threatening. In this report two asymptomatic cases of choroidal osteoma which were detected on routine ophthalmological examination

Choroidal thickness changes after intravitreal dexamethasone implant injection for the treatment of macular EDEMA due to retinal vein occlusion

PubMedID: 27870799Purpose: To investigate changes in choroidal thickness after intravitreal injection of a dexamethasone implant for macular edema due to retinal vein occlusion. Methods: Thirty-one eyes of 31 patients, treated with a single dose of a dexamethasone implant for retinal vein occlusion-associated macular edema, were included. Subfoveal choroidal thickness (SFCT) and central macular thickness of the affected eyes were compared with those of the normal contralateral eyes at baseline and 1, 3, and 5 months after injection. Results: The mean SFCT of the affected eyes (296.3 m ± 61.6 m) was significantly higher than that of the contralateral eyes (251.2 m ± 57.7 m; P < 0.001) at baseline. After injection, the mean SFCT was decreased compared with baseline in the treated eyes at months 1, 3, and 5. There was a correlation between SFCT and central macular thickness in the affected eyes at baseline (r = 0.397, P = 0.027). The change in SFCT was not correlated with the change in central macular thickness after injection. In the contralateral eyes, the mean SFCT did not change significantly. Conclusion: Subfoveal choroidal thickness in eyes with macular edema due to retinal vein occlusion was higher than that of the contralateral eyes. Intravitreal injection of a dexamethasone implant was associated with a reduction in the choroidal thickness of the treated eye

Endogenous endophthalmitis caused by diphtheroid bacillus

PubMedID: 23941569Diphtheroids were generally regarded as nonpathogenic contaminants, but recent clinical studies have emphasized that they may cause serious systemic and ocular disease mostly in patients with underlying medical conditions. In this study we present a case report of acute onset endogenous endophthalmitis associated with heavy growth of diphtheroids on the culture of anterior chamber fluid sample in a 46-year-old man with uncontrolled diabetes mellitus. He did well after appropriate treatment and a functional vision was restored. This case highlights the importance of proper management for the outcomes of patients with endogenous endophthalmitis. It is also significant to be cautious about a life-threatening medical status in a patient with such presentation. © Informa Healthcare USA, Inc

To the editor

PubMedID: 25011029[No abstract available

Intravitreal aflibercept for management of subfoveal choroidal neovascularization secondary to angioid streaks

PubMedID: 26458482[No abstract available

Topical mitomycin C for the treatment of conjunctival tumor

PubMedID: 17183195Background: To evaluate the efficacy of topical mitomycin C (MMC) for the treatment of conjunctival tumor in a prospective design. Methods: Nine patients (nine eyes) with conjunctival tumor were studied. The patients received topical MMC 0.04% four times daily by one to six courses. Each course consisted of medication for consecutive 7 days followed by 1 week without medication. Follow-up was conducted on patients for control of disease, and side effects. Results: In 7 patients, the tumor completely disappeared during the mean follow-up period of 24.57 ± 5.94 months (range 18-35 months) with no recurrence. In 1 patient, there was no regression of the tumor, and in 1 patient cessation of the treatment was needed because of an adverse effect of the drug. Conclusion: Topical MMC is effective for the treatment of conjunctival tumor. Longer follow-up and large series are needed to assess the duration of tumor control. Copyright © 2007 S. Karger AG