Authors:É. Hidvégi, E. Kovács-Csetényi and Gy. Keébe
The crystallization of Al-Ce alloys was studied by DTA. The melting and freezing DTA curves of the investigated alloys exhibit two peaks, corresponding to the transformations of a high-purity phase and the eutectic phase, respectively. The peaks could be separated during both freezing and melting by changing the heating or cooling rate. The final temperature of the phase transformation is marked by the starting temperature of the second peak. A slight shoulder on the DTA peak, even on the opposite side to the maximum point, may correspond to the final temperature.
Authors:Balázs Kovács, I. Czinkota, L. Tolner and Gy. Czinkota
distribution (PSD) is one of the most important fundamental physical properties
of soils, as it determines their physical, chemical, mechanical, geotechnical,
moreover environmental behaviour. Although the measurement of PSD with
different techniques is commonly performed in soil laboratories, their
automation and continuous PSD curve generation have not been solved yet. However, there are some physical principles,
various sensors and different data storing methods for measuring the
density-time function. In the present paper a possible solution is introduced
for the measurement of the soil particle density database as a function of
settling time. The equipment used for this purpose is an areometer that is
widely used e.g. for determining the sugar content of must, or the alcohol
content of distilled spirits, etc. The device is equipped with patent pending
capacitive sensors on the neck of the areometer. It measures the changes in the
water levels nearby the neck of the areometer in 1 μm units with <10
μm accuracy. The typical water level changes are 3-5 cm, which makes
possible a very accurate determination of particle density changes due to
settling in particle size analysis. The measured signals are stored in the
equipment's memory and can be downloaded to the controller computer via a
modified USB port. Data evaluation can be carried out online or later. The
large number of measured data points led to the introduction of a new
evaluation method, the Method of FInite Tangents or shortly the “FIT Method”.
The dispersed soil particle system is considered as the aggregation of many
mono-disperse systems. From this it follows that the measured density-time
function can be divided into grain size fractions with tangent lines drawn to
finite, but optional points. These tangent lines are suitable for calculating
the settling speed of a given fraction, as the changing speed of density is
equal to the multiplication of settling speed and mass of the given grain size
fraction. The settling speed of all fractions is calculable by using the Stokes
law, so the mass of all of the floating fraction can be calculated. Because the
soil suspension is a poly-disperse system, the measured density decrease can be
considered as an integration of finite mono-disperse systems. From this, it
follows that it can be interpreted as the sum of linear density vs. time
functions. If the mass of each grain size fraction is known, the particle size
distribution is calculable. The method is relatively easily programmed
and the intervals of grain size fractions are freely adjustable, so with this
program almost all types of particle size distribution are calculable, not only
those being uniform. Using the appropriate controller and evaluation program,
soil particle size distribution can be calculated immediately after downloading
the measured data. This technique does not need more sample preparation than
past methods. The automated reading lessens the manpower required for
performing the measurement - which also reduces human error sources - and
provides very detailed PSD data that has advantages, among others, like
revealing multi-modality in the particle-size distribution.
Authors:Gy. Vas, I. Blechschmidt, T. Kovács and Károly Vékey
Solid phase microextraction (SPME) coupled to fast capillary gas chromatography was used for monitoring the wine fermentation process. This combination offers a simple, quick and sensitive approach suitable for characterization of head-space components of wines during the fermentation process without a complicated sample preparation procedure. In this work this method was used to observe the differences in aroma production between three different commercial yeasts and the indigenous yeast flora.
Authors:P. Bukovics, L. Gy. Szabó, Zs. Orosz-Kovács and Á. Farkas
The knowledge of nectar composition in entomogamous fruits, including sour cherry cultivars, is of high importance, since pollinator insects have their own taste-preference, which can influence pollination, and hence fruit yield. The floral secretory product of several sour cherry cultivars was studied from 1997 to 2000, in order to determine the floral insect attraction of the cultivars. Here the nectar composition of two major cultivars, an autofertile ('Újfehértói fürtös') and an autosterile one ('Pándy 48'), will be presented. Samples were collected at the Research and Extension Centre for Fruitgrowing, Újfehértó, Hungary. Nectar was drained from the flowers with a microcapillary, following a 24-hour isolation. Sugar components of the floral secretory product were determined by thin layer chromatography, quantitative analysis was carried out by densitometry. When evaluating the results, air temperatures and precipitation data during sample taking were also taken into consideration. The nectar of both studied cultivars contains all three major sugar components: sucrose, glucose and fructose. In most seasons the total sugar concentration reached the apicultural threshold value (100 mg/ml). On the basis of the sucrose/(glucose+fructose) quotient the nectar of 'Újfehértói fürtös' belonged to the sucrose-rich group each year, like the majority of sour cherry cultivars, whereas the secretory product of 'Pándy 48' could be classified into the sucrose-dominant category in one of the seasons. The nectar sugar composition of 'Újfehértói fürtös' varied to a great extent according to the seasons, while the sugar components in the nectar of 'Pándy 48' were rather stable in the four seasons of study, their amounts changing to a small extent, effected by microclimatic factors.
Authors:J. Kőmives, S. Gál, K. Tomor and Gy. Kovács
Thermogravimetry was applied in studies of aluminium foils for electrolytic capacitors. Scanning electron microscopy, X-ray diffraction and surface area determination were also used in the interpretation of the results.
Authors:Gy Kovács, Z. Petrovszki, J. Mallareddy, G. Tóth, Gy Benedek and Gyöngyi Horváth
This study reports on the in vivo effects of four endomorphin-2 (EM-2) derivatives (EMD1-4) containing unnatural amino acids, i.e. 2-aminocyclohexanecarboxylic acid (Achc2), para-fluorophenylalanine (pFPhe4), β-methylphenylalanine (βMePhe4) and/or 2′,6′-dimethyltyrosine (Dmt1). After induction of osteoarthritis by monosodium iodoacetate into the ankle joint of male Wistar rats, a chronic intrathecal catheter was inserted for spinal drug delivery. The mechanical threshold was assessed by a dynamic aesthesiometer. Intrathecal injection of the original EM-2 and the ligands (0.3–10 μg) caused dose-dependent antiallodynic effects. The comparison of the different substances revealed that EMD3 and EMD4 showed more prolonged antinociception than EM-2, and the effects of the highest dose of EMD4 were comparable to morphine, while EMD3 caused paralysis at this dose. The potency of the different ligands did not differ from EM-2. The results show that the derivatives of EM-2 have similar in vivo potency to the original ligand, but their effects were more prolonged suggesting that these structural modifications may play a role in the development of novel endomorphin analogues with increased therapeutic potential.
Human presence leaves an imprint not only on its environment but also on the soil cover. Soils are capable of preserving the signs of all the natural and human-induced activities that ever affected them. Via the identification and understanding of these signs it is possible to reconstruct ancient environments and obtain an insight into the lives of ancient societies. This has been successfully proven in numerous studies in Hungary (e.g. BARCZI et al., 2009; KRAUSZ, 2014; PETŐ, et al. 2015). This paper aims at furthering the understanding and reconstruction of the history of the Százhalombatta-Földvár tell site by analysing soil science data. Tell sites are very complex, so parallel to traditional archaeological investigation, a range of natural sciences (e.g. plant, animal and geological sciences) are involved in their analysis. In this study, soil science techniques, namely soil analysis and thin-section soil micromorphological analysis were employed to gain an insight into the past 4 000 years of the settlement’s history. The intensity and the variability of human activities are also investigated. The results revealed very intensive human influence and significant environmental changes in Százhalombatta-Földvár, demonstrating the importance of the area.