Clean bed head-loss of various filter media

Granüler filtrasyon su arıtımında yaygın olarak kullanılan bir arıtma yöntemi olup bu prosesin tasarım ve işletmesi açısından yük kayıpları büyük önem taşımaktadır. Bu çalışmada laboratuvar ölçekli bir filtrasyon kolonunda sık kullanılan farklı filtre malzemeleri için temiz yatak yük kayıpları belirlenmiştir. Karışık boyutta elde edilen malzemelerin eleme işlemi ile fraksiyonlarına ayrılması sonucu 6 kum, 5 perlit, 8 garnet ve 3 kırık cam fraksiyonu elde edilmiştir. Karşılaştırma amacıyla küreler ile de deneysel çalışma yürütülmüştür. Deney düzeneği filtredeki hidrolik koşulların da etkisini incelemek amacıyla yüksek hızlarda da veri elde edilebilecek şekilde tasarlanmıştır. En yüksek yük kayıpları malzemenin çapına da bağlı olarak 0.1 m/sn filtre hızında 5-6 m olarak gözlenmiştir. Filtrasyon hızı ile yük kaybının lineer olmayan bir şekilde değiştiği tüm malzeme türleri ve her bir fraksiyon için teyit edilmiştir. Aynı zamanda gözeneklilik ve tanecik çapı parametrelerinin yük kaybı üzerindeki etkisi incelenmiştir. Yaklaşık olarak aynı tanecik çapındaki kum, perlit ve garnet yataklarında yük kaybı oluşumu karşılaştırmalı olarak incelenmiş ve gözenekliliğin en düşük olduğu kum yatakta en yüksek yük kaybı elde edilmiştir. Küresellik ile ifade edilen malzeme şeklinin gözenekliliği etkileyen bir unsur olduğu ortaya konmuştur. Tane çapının yük kaybı üzerindeki etkisi kum ve garnetin farklı fraksiyonlarından oluşan kapsamlı bir aralıkta incelenmiş ve her iki malzeme türü için de tane çapı küçüldükçe yük kaybının arttığı gözlenmiştir. Anahtar Kelimeler: Filtrasyon, granüler malzeme, temiz yatak, yük kaybı, gözeneklilik, küresellik.Granular filtration is a process that is widely used for removing particulate matter from water. The granular media filtration process is affected by the properties of the filter media including grain size, bed porosity and specific surface area. Especially, determination of clean bed head loss is important in the design and operation of filters. Clean bed head-loss of various common filter media obtained from several sources was determined in a laboratory scale filter column. The cylindrical column made of plexiglass was 4 cm in diameter and 2 m in height. It was connected to a water tank through a series of pipes and valves. The water tank was filled with tap water and served as a water reservoir for the filtration column. A constant speed centrifugal pump drew water from the tank and pumped it to the top of the column. In addition, the system allowed the water to flow upwards in the column to achieve various porosity ranges as well as to fluidize the media and bleed any residual air. In the filtration cycle the water travelled down the filter column through a bed of media and was then returned to the water tank. A cartridge filter was used to trap possible suspended solids thus ensuring the recirculated water remained clean. To measure the head-loss across the media bed as water passed through it, piezometer taps at the top and bottom of the media were connected to a water-air manometer, as well as a mercury manometer and a differential pressure transducer. Flow rate of the equipment being used determined the choice of the instrument. Flow rate was measured by an electromagnetic flow meter across the range of 0.17-17L/min. Because the density and dynamic viscosity of the fluid changes with temperature, a Pt-100 thermometer was installed on the column and temperature was monitored continuously. Once the media had been loaded in the column, the filter was operated in the down flow mode and the flow rate was gradually increased and then decreased to a minimum value prior to head-loss measurements. As such the compaction of the media during the experiment was prevented. The porosity of the filter bed was determined separately for each run using the weight of the filter media introduced to the column, the height of the filter bed, the inside diameter of the filter column and the specific gravity of the media. The media which were normally composed of different grain sizes were sieved and 6 fractions of sand, 5 fractions of perlite, 8 fractions of garnet and 3 fractions of crushed glass were obtained. Experiments were also conducted on using glass beads for comparison. Experimental set-up was designed so as to obtain data at high filtration rates in order to evaluate the hydraulic behavior in the column. The maximum head-loss was measured as 5-6 m for 0.1 m/s filter rate. Head-loss measurements were made? for a minimum of three porosities for each medium. These porosities corresponded to the maximum compaction that could be obtained by directly tapping on the column, gradual shut off of backwash water and an intermediate value between these. For each type of medium and fraction it was confirmed with literature that there exists a non-linear relationship between filter rate and head-loss. Besides, effect of porosity and grain size on head-loss was assessed. As the bed consists of uniform particles when a sieved fraction of medium is used instead of its mixed form, more robust evaluations were possible. The sensitivity of head-loss to porosity was examined via extensive experiments. The head-loss occurrence in beds of sand, perlite and garnet of approximately same grain size were compared to each other. The highest head-loss was observed for the bed composed of sand due to the lowest porosity value. Also, experiments were conducted with approximately same size of sand and glass beads separately but at the same porosity. It was noticed that sand caused higher head-losses, which were more easily observed at higher filter rates. Different porosities were achieved by directly tapping to the column or gradual shutoff of the backwash water. Also, it was verified that grain shape defined by sphericity affected the porosity. The sphericity of crushed glass being an angular medium was found to be around 0.5. The porosity range obtained with this media showed to be higher than other filter media. To evaluate the effect of grain size on head-loss, several fractions of sand and garnet were compared and an inversely proportional relation was observed independent of the type of the medium. Keywords: Filtration, granular material, clean bed, head-loss, porosity, sphericity

Intratympanic Steroid Treatment in Méniére Disease

Méniére disease (MD) is characterized by vertigo attacks, hearing loss, tinnitus, and aural fullness. Although the exact treatment of MD is lacking, several treatment options including conservative, medical, and surgical aim to control symptoms. Recently, an increasingly used treatment method called intratympanic steroid (ITS) treatment is applied to patients suffering from MD. In which step the ITS takes part for MD treatment protocol is not certain. But common wisdom is that ITS can be used in patients with intractable MD to conservative and medical treatment before applying intratympanic gentamicin and surgical treatments

Associations among high altitude, allergic rhinitis, and bronchial hyperreactivity

Allergic respiratory diseases are common public health problem. Although several treatment options, some of patients cannot manage to get satisfactory recovery. High altitude (HA) is shown as a natural additive and/or salvage therapy option for this patient group. We aimed to present the effect of HA on allergic rhinitis and bronchial hyperreactivity in company with literature

Is metabolic syndrome associated with obstructive sleep apnea in obese adolescents?

WOS: 000367581700004PubMed ID: 26156956Objective: To investigate whether there is an association between metabolic syndrome and obstructive sleep apnea syndrome (OSAS) in obese adolescents. Methods: In total, 240 pubertal children or prepubertal children older than 11 y recruited consecutively from the pediatric endocrinology unit, obesity clinic. Patients with tonsillar and adenoid hypertrophy (grade 3/4), systemic illnesses, or chronic drug usage were excluded. After anthropometric measurement and laboratory study, patients were divided into two groups according to metabolic syndrome (MS): MS and non-MS. Overnight polysomnographic evaluation was performed and 104 subjects were included for statistical analysis. The two groups were compared in terms of sleep efficiency, number of awakenings per night, oxygen desaturation index, snoring time, and obstructive/central/mixed apnea-hypopnea index (AHI). Results: Of the obese adolescents, 51 had MS and 53 did not. The AHI was >= 1 in 25 of the 53 non-MS children (47.2%) and in 25 of the 51 MS children (49%). The median obstructive AHI value was 0.9 (0.2-2.4) and total AHI was 0.9 (0.2-2.5) in the MS group; these values were 0.9 (0.25-3.55) and 0.9 (0.3-3.55), respectively, in the non-MS group. Obstructive, central, mixed, and total AHI values in the MS and non-MS groups were not statistically significantly different (p > 0.05). Conclusions: In our study, we did not find an association between MS and sleep apnea in obese adolescents

Nazal Fraktürlerin Değerlendirilmesi ve Adli Tıp Yaklaşımı

Bu çalışmada kliniğimize başvuran nazal fraktür olgularının değerlendirilmesi ve nazal fraktürlerde güncel adli tıbbi yaklaşımın sunulması amaçlanmıştır. Bu amaçla Ocak 2009-Ocak 2010 tarihleri arasında kliniğimize maksillofasyal fraktür ile başvuran olgulardan nazal fraktür tanısı alan ve tedavi edilen hastalar geriye dönük olarak değerlendirilmiştir.Çalışmamızda toplam 580 olgu saptandı. Nazal fraktür sıklığı tüm maksillofasyal kırıklar arasında %84,9’ du (n:580/683). Ortalama başvuru yaşı 28,4 idi (8 ay-84 yaş). Olguların 479’ u (%82,6) erkek iken 101 ’i (%17,4) kadındı. En sık rastlanan 3 neden etkili eylem (n:216, %37,2), düşme (n:122, %21) ve araç içi trafik kazası (n:34, %5,9) idi. Fraktürlerin 41’ i (%7,1) açık kırıkken, 539T (%92,9) kapalı fraktürlerdi. Kapalı fraktürler arasında 205 (%35,3) hastada deplase nazal fraktür saptanırken deplase olmayan nazal fraktür sayısı 334 (%57,6) idi. Nazal fraktürler maksillofasyal travmalar içinde sık rastlanılır ve erken dönem komplikasyonlar dışında uzun dönemde burun yapısında değişikliğe neden olabilir. Etyoloji sıklıkla etkili eylem, trafik veya iş kazası gibi nedenler olduğundan tüm olguların kayıt altına alınması ve bu olgularda güncel adli tıbbi yaklaşımın bilinmesi önemlidir. Anahtar kelimeler: Nazal fraktür, etyoloji, adli tı

Microanatomic analyses of extratemporal facial nerve and its branches, hypoglossal nerve, sural nerve, and great auricular nerve

Objective: To investigate microanatomic organizations of the extratemporal facial nerve and its branches, hypoglossal nerve, sural nerve, and great auricular nerve. Methods: Nerve samples were dissected in 12 postmortem autopsies, and histomorphometric analyses were conducted. Results: There was no significant difference between the right and left sides of the nerve samples for the nerve area, fascicle area, number of fascicles and average number of axons. The lowest mean fascicle number was found in the hypoglossal nerve (4.9 ± 1.4) while the highest was in great auricular nerve (11.4 ± 6.8). The highest nerve area (3,182,788 ± 838,430 μm2), fascicle area (1,573,181 ± 457,331 μm2) and axon number (14,772 ± 4402) were in hypoglossal nerve (p < 0.05). The number of axons per unit nerve area was higher in the facial nerve, truncus temporofacialis, truncus cervicofacialis and hypoglossal nerve, which are motor nerves, compared to the sural nerve and great auricular nerve, which are sensory nerves (p < 0.05). The number of axons per unit fascicle area was also higher in motor nerves than in sensory nerves (p < 0.05). Conclusion: In the present study, it was observed that each nerve contained a different number of fascicles and these fascicles were different both in size and in the number of axons they contained. All these variables could be the reason why the desired outcomes cannot always be achieved in nerve reconstruction

A Huge Cemento-Ossifying Fibroma of Paranasal Sinus: A Case Report

Cemento-ossifying fibroma is a well-bordered, slow-growing, benign fibro-osseous disease. Although its localization is generally in the mandible, it can be seen in any area of the craniofacial region. Radiology and histopathology help to diagnose the condition. Treatment is based on close observation and/or surgical excision. In this case, we report the case of a 62-year-old male patient who had a large radiological appearance, cemento-ossifying fibroma in the paranasal sinuses