428 research outputs found
Examınatıon of effects of dıfferent workıng fluıds on engıne performance in a rhombıc drıve stırlıng engıne
No full textBu çalışmada, rhombic hareket mekanizmasına sahip bir beta tipi Stirling motorunun performans testleri, LPG yakıcı bir ısıtıcı kullanılarak hava ve helyum olmak üzere iki farklı çalışma akışkanı ile gerçekleştirilmiştir. Motorda sürtünmeleri azaltmak amacıyla rhombic hareket mekanizması kullanılmıştır. Deneyler 700±10 °C sıcak uç ve 27±5 °C soğuk uç sıcaklığında 2, 3, 4, 5, 6 ve 7 bar şarj basınçlarında gerçekleştirilmiştir. Çalışma akışkanı olarak hava ile yapılan deneylerde maksimum motor momenti ve motor gücü 6 bar şarj basıncında 455 dev/dk motor devrinde sırasıyla 12,13 Nm ve 578,32 W olarak ölçülmüştür.Helyum ile yapılan deneylerde ise maksimum motor momenti ve motor gücü 7 bar şarj basıncında sırasıyla 552 dev/dk motor devrinde 11,76 Nm ve 640 dev/dk motor devrinde 684,39 W olarak elde edilmiştir.Inthisstudy, performancetests of a beta typeStirling engine withrhombicdrivemechanismwerecarriedoutwithtwodifferentworkingfluids as airandheliumusing a LPG burnerheater. Inordertoreducefriction in the engine, rhombicdrivemechanismwasused. Theexperimentswerecarriedout at 700±10 °C hot endand 27±5 °C coldendtemperatureand at 2, 3, 4, 5, 6 and 7 bar chargepressures. Themaximum engine moment and engine powerweremeasured as 12,13 Nmand 578,32 W at 6 bar chargepressureand 455 rpm in theexperimentswhich is carriedoutwithair as theworkingfluid.Intheexperimentswithhelium, themaximum engine moment and engine powerwereobtained as 11,76 Nm at 552 rpmand 684,39 W at 640 rpm at 7 bar chargepressure, respectively
Changes in Quality of Dried Fig Fruit and Processed Fig Products under Cold and Ambient Storage Conditions
No full text6th International Postharvest Symposium -- APR 08-12, 2009 -- Antalya, TURKEYTurkey has a significant share in the world dried fig (Ficus carica 'Sarilop') trade. Dried fig is generally exported as semi-processed intermediate goods. During the last years, there are attempts to develop new processed products from fig paste. The research was carried out in 2006-2007 to determine the quality changes that limit market life of sun-dried fig fruits destined for direct consumption and sweets prepared from fig paste. Dried fig fruit (manipulated as Lerida type) and two products processed from fig (fig delight with walnut and sesame coated paste) were stored under cold (3 +/- 0.5 degrees C, 55-65% relative humidity) and ambient storage conditions for 12 months. Samples were taken monthly to monitor quality changes and microbial load. Under ambient storage conditions, quality losses started in dried fig and fig delight after 7 months and in sesame coated paste after 8 months of storage due to increased temperatures and lower relative humidity in the spring. Cold storage conditions extended storage ability and no significant changes were observed for a 12 month period.Int Soc Hort Sci (ISHS)TARIS Research and Development Center [AR-GE 2006 I/1]This study was partially funded by the TARIS Research and Development Center under grant AR-GE 2006 I/1
Effects of topical antiglaucomatous medications on central corneal epithelial thickness by anterior segment optical coherence tomography
No full textPurpose: To evaluate the effect of topical antiglaucomatous medications on central corneal epithelial thickness measured by anterior segment optical coherence tomography. Materials and methods: A total of 153 eyes of 153 patients using topical antiglaucomatous medications and 110 eyes of 110 control subjects were enrolled. Glaucoma type, duration of therapy, the number of drugs, and drops/day were noted in the patient group. Patients and control subjects underwent ocular examinations including Schirmer test, slit lamp examination for tear film break-up time, and anterior segment optical coherence tomography for central corneal thickness and central corneal epithelial thickness. Central corneal epithelial thickness and other data were evaluated separately with regard to glaucoma type, duration of therapy, the number of drops, and drugs in the patient group. Results: The mean ages of the patients and controls were 60.1 +/- 10.8 and 58.7 +/- 11.2 years, respectively. The groups were similar with regard to mean age and gender (p = 0.058, p = 0.734, respectively). The median (interquartile range) central corneal thickness was 536 (54) mu m in patients and 552 (53) mu m in controls (p = 0.011). The median (interquartile range) central corneal epithelial thickness of patients and controls were 56 (4) mu m and 60 (8) mu m, respectively (p < 0.001). The median (interquartile range) tear film break-up time and Schirmer were 12 (6) s and 10 (8) mm in patients and 16 (2) s and 18 (4) mm in controls, respectively (p < 0.001, p < 0.001). In patient group, there was no significant difference in the median central corneal thickness, central corneal epithelial thickness, and tear film break-up time in terms of glaucoma type, duration of therapy, the number of drugs, and the number of daily drops. Only the median Schirmer test was found to be statistically lower in terms of number of daily eye drops (p = 0.039). Conclusion: Using topical antiglaucomatous medications seems to affect the central corneal epithelial thickness in glaucoma patients. Central corneal epithelial thickness was thinner in glaucoma patients than controls. Anterior segment optical coherence tomography might be helpful to evaluate the effect of antiglaucomatous medications on central corneal epithelial thickness during treatment
Static and dynamic properties of CN/Cu(001) surfaces and oxidation, dissociation and bimolecular debarboxylation of isocyanate species adsorbed on Cu(001)
No full textThis dissertation presents an outlines my investigations of static and dynamic properties of adsorbed cyanide (CN) and isocyanate (-NCO) species as well as some of their chemistries. Surface bound CN-containing species have not previously been studied extensively, partially due to the inapplicability of fundamental e-beam based surface analysis techniques for investigations. I had the opportunity in my studies to employ multiple surface probing techniques, i.e. HAS, XPS, NEXAFS, TPD and RAIRS, to compile and cross-examine information from CN, –NCO, and derived species, adsorbed on the Cu(001) surface. While angle resolved He atom scattering (HAS) was employed to identify and investigate the ordered superstructure of CN/Cu(001) surfaces, TOF-HAS was employed to investigate its dynamic properties. The CN/Cu(001) surface induced unprecedented simultaneous coherent He diffraction with a large “classical” multiphonon backscattered He intensity. A superstructure is implied that contains both rigidly bound CN species, which maintain the long range c(10x6) translational symmetry, together with bound highly-dynamic CN species that exhibit large thermally induced displacements. The NEXAFS measurements suggest multiple spatial binding configurations for the adsorbed CN moieties. In addition, TPD spectra of C2N2 desorption from CN/Cu(001) surface were analyzed, using my newly developed method, to determine the activation energies for desorption as a function of CN coverage. There are two reactions of NCO species examined in my studies. The first is the newly discovered mutual reaction between NCO species. This type of interaction had not been seen before, as it is essentially difficult to prepare pure NCO/metallic surfaces. Copper was chosen as a substrate as HNCO exposures of Cu(001) at RT, followed by spontaneous H2 desorption, do produce NCO only surfaces. A thermal treatment of the surface, at 573K, leads to a bimolecular decarboxylation of NCO, leaving a carbodimide species (NCN) on the surface. The sp-hybridized linear NCN moieties, which are bound nearly parallel to the substrate, show high thermal stability. The second reaction of NCO, which I have studied, is its oxidation. In particular, the effect of CN coadsorbates on the oxidation of NCO was studied. It was found that the presence of CN catalyzes a dissociation reaction of NCO species on Cu(001).Ph. D.Includes bibliographical referencesby Erkan Ziya Ciftlikl
The Effect of Combination of Hot Water with Some Postharvest Treatments on Quality and Storage Life of 'Satsuma' Mandarin
No full text6th International Postharvest Symposium -- APR 08-12, 2009 -- Antalya, TURKEYIn the present study, hot water and the combination of some postharvest treatments were examined to evaluate the effect of postharvest decay and storage ability of 'Satsuma' mandarin (Citrus Unshiu Mar.). During the first year of the study, fruit were treated with hot water at various temperatures and durations. In the second year, the experiments were conducted with 53 degrees C for 3 min alone, the treatment was found successful in the first year trial, or as combined with low dose of imazalil (200 mu g ml(-1)), with yeast isolates + low dose of imazalil and recommended dose of imazalil (1000 mu g ml(-1)). Chlorine was also tested as an alternative at the dose of 100 mu g ml(-1). The control fruit were dipped into water at 23 degrees C for 3 min. As the result of both years, it was found that the highest temperature of hot water treatment (56 degrees C) caused heat damage and increased decay development on fruit and affected all fruit quality parameters negatively. Scanning electron microscopy examination showed that fruit surface treated with hot water at 53 degrees C for 3 min appeared relatively homogeneous, stomata were closed and surface cracks were sealed when compared to control fruit. When the decay development reached to 15% on control fruit, dipping into hot water at 53 degrees C and imazalil alone or their combination completely inhibited decay incidence. The results confirmed that hot water dipping could be used commercially on 'Satsuma' mandarins because it inhibits postharvest losses and can be combined with low doses of fungicides.Int Soc Hort Sci (ISHS)Ege University Research FoundationEge University [2001 ZRF 029]This study was supported by the Ege University Research Foundation (2001 ZRF 029)
Acta Horticulturae
No full textThe main objective of the production and distribution chain of fruit is to ensure that the product reaches the consumer in its optimal state of maturation. Prior to commercialization, the fruit stays in cool chambers for a short time. Nowadays, used methods by packinghouses are too expensive and they only provide samples of the atmosphere in some points of the chamber. Finally, these methods are too simple and unreliable. IVIA, through the research project "Sensogest", is developing an infrastructure capable of acquiring, pre-processing and transmitting information about the atmosphere of the cool rooms in a packinghouse to a remote station. This work reviews the infrastructure that IVIA is developing in order to acquire relevant information related to maturation of fruits (carbon dioxide and ethylene production rate) and storage conditions (temperature and relative humidity) in cool rooms. The first tests to design a new ethylene sensor, the performance of the developed CO2 detector and the ability of a communication system based on the AS-Interface to monitor signals from temperature and relative humidity sensors will be shown
Acta Horticulturae
No full textNew hydroxypropyl methylcellulose (HPMC)-lipid edible composite films and coatings containing food preservatives with antifungal properties were developed to control citrus postharvest green and blue molds, caused by the pathogens Penicillium digitatum (PD) and Penicillium italicum (PI), respectively. Tested chemicals were mainly salts of organic acids, salts of parabens, and mineral salts, all classified as food additives or generally recognized as safe (GRAS) compounds. The antifungal activity of stand-alone edible films were evaluated in vitro using disk diameter tests. Selected edible coatings containing food preservatives were tested in vivo on 'Ortanique' hybrid mandarins to determine their curative (coated 24h after fungal inoculation) and preventive (coated 24h before fungal inoculation) activity. Disease incidence and severity were determined on fruit artificially inoculated with the pathogens and incubated at 20 degrees C and 90% RH for 7 days. Film disks containing sodium salts of parabens and the organic acid salts potassium sorbate (PS) and sodium benzoate (SB) were the most effective to inhibit both PD and PI. The use of mixtures of parabens or organic acid salts did not provide any additive or synergistic effect for in vitro pathogen inhibition when compared to the use of single chemicals. On 'Ortanique' mandarins treated after fungal inoculation, paraben-, PS-, and SB-based coatings only reduced the incidence of green and blue molds by about 40 and 20%, respectively. However, HPMC-lipid coatings containing a mixture of PS and sodium propionate (PS+SP) reduced disease incidence by more than 75 and 65%, respectively. On these fruit, the severity (lesion size) of both molds was reduced by more than 90%. The incidence and severity of both green and blue molds on mandarins coated before inoculation (preventive activity) was not significantly affected by the application of any of the antifungal coatings
Fruit Quality and Postharvest Performance of ‘Cripps Pink’ Apple in Relation to Withholding Irrigation
No full textWe investigated the effects of withholding irrigation (WHI) at various stages of apple fruit development in improving fruit quality at harvest, particularly fruit colour without adversely affecting storage life and quality. WHI treatments were applied during stage II and III of fruit development commencing from 135, 145 and 155 days after full bloom (DAFB). Treatments were (i) T1, commercial irrigation as a control, (ii) T2, WHI from 135 to 153 DAFB, (iii) T3, WHI from 145 to 175 DAFB, and (iv) T4, WHI from 155 to 200 DAFB. WHI applied in T3 significantly reduced leaf water potential, 10 days after the commencement of WHI. WHI treatments did not significantly affect the cumulative fruit drop on 195 DAFB than T1. WHI treatment (T3) enhanced red skin colour, concentration of total anthocyanins, soluble solids concentration and firmness at harvest as compared to T1. Fruit from T3 stored at 0±0.1°C, 90±2% RH for 70 and 140 days retained higher firmness (>68N) and SSC (>15°Brix) as compared to T1.However, prolonged cold storage periods decreased titratable acidity of the fruit from irrespective of WHI treatments. WHI fruit from T3 stored for 140 days showed increased levels of ascorbic acid and total antioxidants in the pulp as compared to other treatments. In conclusion, WHI applied 145 to 175 DAFB (middle of stage II) improved fruit colour and other major fruit quality parameters at harvest without adversely affecting postharvest quality and also reduced water use
Time-resloved Reflectance Spectroscopy for the non-destructive detection of inner attributes and deflects of fruit
No full textA review of the main results obtained by Time-resolved Reflectance Spectroscopy (TRS) and of its possible applications for the detection of inner attributes and defects in fruit is presented. Common spectroscopy techniques employ continuous wave light and measure the diffusively remitted intensity which is determined by both the absorption and the scattering properties of the sample. Light absorption is related to chemical properties, while scattering to physical structure. Quantification of absorption and scattering may be obtained by space- or time-resolved methods. TRS is a technique based on the measurement of the temporal delay and broadening experienced by a short laser pulse while traveling through a turbid medium and explores a volume of pulp at a depth of 1-2 cm. TRS has been used to detect some internal defects and disorders in the intact fruit, such as brown heart, internal browning, internal bruises, water soaked tissue, as well as internal attributes related to maturity, texture and cell wall structure. The scattering coefficient was found to be related to the translucency of tissue and was used to detect internal bruises and water soaked tissue (i.e., water core in apples and Botrytis decayed kiwifruits). The scattering coefficient was related to pectin composition and textural properties of apples such as firmness and mealiness. Absorption coefficient in the 600-700 nm region can detect brown heart in pears and internal browning in apples. The absorption coefficient at 670 nm is related to fruit maturity and it was used in nectarines to predict their softening time and to detect too immature fruit which are not able to ripen. Being non-destructive, TRS measurements can be repeated on the same fruit, following the development and the changes occurring with ripening or storag
Effect of Different Temperatures on Purslane Quality and Total Lipid Content
No full text6th International Postharvest Symposium -- APR 08-12, 2009 -- Antalya, TURKEYPurslane (Portulaca oleracea L.) is widely used in Mediterranean countries in salads and soups. Recently, there is an increasing interest in purslane due to its Omega-3 fatty acid and antioxidants contents. In Turkey, purslane is harvested by pulling from the soil, washed and marketed in bunches with its roots, at ambient temperatures. Marketing with roots brings different sanitation problems. Besides, marketing without any refrigeration causes losses in quality, alongside nutrients. In this study, the changes in visual quality, total lipid content and antioxidant power at default marketing conditions was examined. Both visual and nutritional quality was better preserved at 5 degrees C and in clam-shell containers. Widely used marketing conditions, i.e., bunches at 20 degrees C, caused significant product, quality, total lipid and antioxidant losses.Int Soc Hort Sci (ISHS
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