Analysis of Hue Spectra During Storage of Pepper (Capsicum annuum)

Color information is widely used in non-destructive quality assessment of perishable horticultural produces. The presented work investigated color changes of pepper (Capsicum annuum L.) samples received from retail system. The effect of storage temperature (10±2°C and 24±4°C) on surface color and firmness was analyzed. Hue spectra was calculated using sum of saturations. A ColorLite sph850 (400-700nm) spectrophotometer was used as reference instrument. Dynamic firmness was measured on three locations of the surface: tip cap, middle and shoulder. Significant effects of storage conditions and surface location on both color and firmness were observed. Hue spectra responded sensitively to color development of pepper. Prediction model (PLS) was used to estimate dynamic firmess based on hue spectra. Accuracy was very different depending on the location. Firmness of the tip cap was predicted with the highest accuracy (RMSEP=0.0335). On the other hand, middle region cannot be used for such purpose. Due to the simplicity and rapid processing, analysis of hue spectra is a promising tool for evaluation of color in postharvest and food industry

Examination of structural materials’ property changes by vibration diagnostic methods

Az értekezésben három kísérletsorozat és a hozzájuk kapcsolódó új tudományos eredmények kerültek bemutatásra. Az első ismertetett kísérletsorozatban PVC szálakon folytatott hosszú idejű, komplex kúszás-relaxációs kísérletek szerepeltek. Ebben az anyagi viselkedés tanulmányozása mellett az azt leíró anyagi paraméterek számszerű meghatározása volt a célunk. A második kísérletsorozat során a korábbival azonos alapanyagú PVC szálakat vizsgáltunk rezgőhúrként. A szálakat a mérések során egy rezgőasztalon húrként kifeszítve megpendítettük, majd vizsgáltuk a csillapodó rezgőmozgást. A rezgés értékelése révén roncsolásmentes módon kaptunk információt a szálak öregítés hatására bekövetkező tulajdonságváltozásáról. Az értekezésben ismertetett harmadik kísérletsorozat során csövek belső átmérőjének csökkenését modelleztük, mint az egyik jellemző cső tönkremeneteli formát. A kísérletsorozat során a vizsgált csövek belső falára különböző rétegvastagságban cementeszrich réteget vittünk fel, és minden állapothoz kapcsolódóan rezgésdiagnosztikai méréseket végeztünk. Megállapítottuk, hogy a rezgésparaméterek és a sajátfrekvencia értékek változásai egyértelműen jelezték a csövek csökkenő belső átmérőjét.Three series of experiments and the related new scientific results were presented in the dissertation. In the first test series long-term tensile and relaxation tests of PVC fibers were included. The aim was to investigate and describe the behavior of the examined material with sufficient precision using the applied load at constant temperature, and to gain information about the aging process using this model. During the second series of experiments fibers of the same PVC material were examined as vibrating strings. The tests were done on a self-constructed vibrating table, where the fibers were stretched one by one for each measurement as strings by a tensional force. After the diverted and stretched fibers were twanged the motion of the string was recorded and vibration parameters were also measured. The identified parameters made it possible to evaluate the degradation level of the test material in a non-destructive way. Reduction in inner diameter of pipes, as a characteristic failure (for example limescale deposition) was modeled in the third test series. During the experiments screed concrete was applied in different thickness to the inner wall of the pipes. In the different states, vibration tests were performed to evaluate the status of the pipe section and the rate of deposition. Changes of the vibration parameters and natural frequencies clearly indicated the inner diameter decrease of the pipes

Influence of Can Flatness on Heat Dissipation of Aluminium Electrolytic Capacitor

The lifetime of aluminium electrolytic capacitors highly depends on their core temperature. Heat dissipation in general applications happens by the extended cathode, which is in contact with the inner side of the can. In the case of heat sink applications, the most important heat transfer phenomenon is the heat conduction through the bottom of the aluminium can. The quantity of the dissipated heat is in direct proportion to the size of the heat transfer surface. The more dissipated heat may increase the lifetime of the capacitor. Therefore, the flatness value of the can bottom is critical. This paper presents a flatness measurement method, which can successfully replace the equipment for a more complex and more expensive 3D measurement. It discusses an implementation of a measurement environment, where data acquisition and visualization are automated by a LabVIEW-based software. In addition, this study deals briefly with the influence of production processes on the flatness value of the capacitor produced by leading manufacturers

Photodegradation of Timber of Three Hardwood Species Caused by Different Light Sources

In this study, resistance of black locust, beech and poplar wood to photodegradation was tested, applying sunlight, a xenon lamp and a mercury vapour lamp. The irradiation time was 200 hours for sunlight and the xenon light and 20 hours for the mercury light. The changes were monitored by colour measurements and infrared spectroscopy. The colour change of black locust was more intensive at the beginning of the irradiation than that of the beech and poplar. The degradation of aromatic structure of lignin (absorbing at 1510 and 1596 cm-1) in black locust was minor compared to the same changes of beech and poplar during the first 10 hours. The mercury lamp induced more intensive changes both in colour and in infrared spectrum than the other two light sources. The results show that the high extractive content of black locust absorbs a considerable amount of light radiation protecting the main chemical components of wood

Evidence for suppression of collective magnetism in Fe-Ag granular multilayers

Evidence for the suppression of collective magnetic behavior of dipolarly interacting Fe nanoparticles is found in Fe-Ag granular multilayers. Interaction of Fe particles located in neighboring Fe layers is studied as a function of the nominal thickness of the Ag layer in between only two Fe layers. The surprisingly increasing interaction with increasing Ag-layer thickness, verified by memory-effect measurements, is explained by the formation of pinholes in the Ag layer at small Ag thicknesses, allowing direct ferromagnetic coupling between Fe particles in neighboring Fe layers which may hinder the frustration of superspins favored by dipolar interactions. At larger Ag thicknesses, the Ag layer is continuous without pinholes and frustration leads to the appearance of the superspin-glass state. The effect of increasing interactions correlates well with the growing deviation at low temperatures of the measured field-cooled (FC) magnetization from the interaction-free FC curve calculated by a model based on the relaxation of two-level systems. Similar phenomenon is reported in a recently published paper (S\'anchez et al., Small 2022, 18, 2106762) where a dense nanoparticle system is studied. The collective magnetic behavior of the particles due to dipolar interactions is suppressed when the anisotropy energy of the individual particles exceeds a certain threshold.Comment: 13 pages, 3 figure

Influence of parameters of drying on laser induced diffuse reflectance of banana discs

Banana discs of 1 cm thickness were immersed into different antioxidant solutions to slow down potentially disturbing discoloration during drying. Samples were randomly split into 8 groups according to the 2^p experimental design. Two antioxidant solutions with 1.66% and 4.59% ascorbic acid, two levels of drying temperature with 50°C and 80°C, two levels of drying time with 6h and 8h were used or adjusted. Laser diodes of seven wavelengths (532, 635, 650, 780, 808, 850 and 1064 nm) were selected to illuminate the surface and light penetration pattern was evaluated on the basis of radial profiles. Profiles acquired at three wavelengths (532, 635 and 650 nm) were found to respond sensitively to adjusted parameters. As a result of drying, intensity decay was observed to move closer to incident point. Significant effect (p<0.01) of temperature, drying time and their interaction was found on extracted descriptive attributes of intensity profiles: full width at half maximum (FWHM), distance of inflection point (DIP) and slope of logarithmic decay (SLD). Beyond their presence, antioxidant concentration was neutral factor without significant contribution to the model. Results were in agreement with reference spectroscopic measurements, especially with NDVI index. Promising results suggest that evaluated method might be suitable for monitoring purposes during drying of fruits

Clinical characteristics and possible drug targets in autosomal dominant spinocerebellar ataxias

The autosomal dominant spinocerebellar ataxias (SCAs) belong to a large and expanding group of neurodegenerative disorders. SCAs comprise more than 40 subtypes characterized by progressive ataxia as a common feature. The most prevalent diseases among SCAs are caused by CAG repeat expansions in the coding-region of the causative gene resulting in polyglutamine (polyQ) tract formation in the encoded protein. Unfortunately, there is no approved therapy to treat cerebellar motor dysfunction in SCA patients. In recent years, several studies have been conducted to recognize the clinical and pathophysiological aspects of the polyQ SCAs more accurately. This scientific progress has provided new opportunities to develop promising gene therapies, including RNA interference and antisense oligonucleotides.The aim of the current work is to give a brief summary of the clinical features of SCAs and to review the cardinal points of pathomechanisms of the most common polyQ SCAs. In addition, we review the last few years promising gene suppression therapies of the most frequent polyQ SCAs in animal models, on the basis of which human trials may be initiated in the near future