Authors:A. Özer, Selcan Turker, Seyda Çolak, Mustafa Korkmaz, Ekrem Kiliç, and Meral Özalp
The use of gamma rays for the sterilization of pharmaceutical raw materials and dosage forms is an alternative method for sterilization. However, one of the major problems of the radiosterilization is the production of new radiolytic products during the irradiation process. Therefore, the principal problem in radiosterilization is to determine and to characterize these physical and chemical changes originating from high-energy radiation. Parenteral drug delivery systems were prepared and in vitro characterization, biodistribution and treatment studies were done in our previous studies. Drug delivery systems (liposomes, niosomes, lipogelosomes and niogelosomes) encapsulating diclofenac sodium (DFNa) were prepared for the treatment of rheumatoid arthritis (RA). This work complies information about the studies developed in order to find out if gamma radiation could be applied as a sterilization method to DFNa, and the raw materials as dimyristoyl phosphatidylcholine (DMPC), surfactant I [polyglyceryl-3-cethyl ether (SUR I)], dicethyl phosphate (DCP) and cholesterol (CHOL) that are used to prepare those systems. The raw materials were irradiated with different radiation doses (5, 10, 25 and 50 kGy) and physicochemical changes (organoleptic properties pH, UV and melting point), microbiological evaluation [sterility assurance level (SAL), sterility and pyrogen test] and electron spin resonance (ESR) characteristics were studied at normal (25 °C, 60% relative humidity) and accelerated (40 °C, 75% relative humidity) stability test conditions.
The alates of
started settling on wheat during first week of January (standard week 1) simultaneously with the activity of its predator,
. However, the population density of this predator at this stage was very less. From standard week 5, the aphid population started increasing steadily and colonies of alates and apterous aphids were seen on leaves and stem. Middle of February to the start of March was the most favourable period for multiplication of this pest. The maximum population of cereal aphid was observed during standard week 10 (second week of March), when wheat (
) crop was in earing stage and the temperature was between 8.5 and 23.1° C along with a relative humidity of 45.7 to 88.3 per cent. The aphid started declining gradually during following weeks, finally disappearing by second week of April (standard week 15). Its predator,
was observed feeding on aphid colonies during standard week 4, which increased steadily till middle of April, when the aphid population started declining. This asynchrony in their population pattern in wheat crop is being contemplated to be the major cause of flare up of the population of this pest. The correlation drawn between different stages of predator and aphid population revealed that the collective contribution of these factors was 93.92 per cent. Abiotic (temperature and relative humidity) and biotic (predator) factors were observed to be significantly influencing the aphid population in this crop ecosystem.
The present paper focuses on the re-evaluation of archive engineering geological data of sic core drillings at one of the new metro stations of Budapest (Kálvin square, metro line 4). More than 1000 data of total coring length of more than 210 meters were used for statistical calculations. The data set includes index of plasticity, skewness, void ratio, water content, dry and water saturated bulk density, relative humidity, angle of friction, cohesion and compressive strength. Based on the data set the engineering geological description of sediments was reevaluated, and sand, clay, silt and bentonite-rich horizons were identified. Three new crosssections were prepared. Statistical analyses proved that there is an increase in cohesion and density of clays and silts with depth, indicating the role of consolidation.
Authors:A. Bigi, M. Borghi, G. Cojazzi, A. Fichera, S. Panzavolta, and N. Roveri
Differential scanning calorimetry and high angle X-ray diffraction analyses were performed on gelatin films, air dried at
different values of constant elongation, crosslinked with glutaraldehyde and examined at constant relative humidity of 75%.
Drawing induces a preferential orientation of the chain segments of gelatin parallel to the stretching direction,and a linear
increase of the renaturation level, calculated as the ratio between the denaturationenthalpy of gelatin films and that of
tendon collagen. The comparison with the results previously obtained on the mechanical properties of the films, puts into
evidence the different contributions of orientation and renaturation on the improvement of the mechanical parameters on drawing.
The results offer important information on the role of glutaraldehyde (GTA) crosslinking on the stability of collagenous materials.
Differential scanning calorimetry (DSC) has been used to probe ordered structures and glassing behaviour for a range of agars containing < 25% w/w water. Most commercial agars are supplied in an ordered (double-helical) state, show an endothermic helix-to-coil transition above 100‡C at low-moisture, and require 90–100‡C for solubilisation in excess water. Agars dried from the coil (single-chain) state show no corresponding endothermic transitions and only require a minimum of 45‡C for aqueous dissolution. Evidence from helix-to-coil transition enthalpies, equilibrium water content as a function of relative humidity, and solid-state13C NMR spectroscopy suggests that water molecules are associated enthalpically with double-helical agar. Single-chain agar is apparently not obtained in a glassy state by direct drying from solution, but in common with double-helical forms, exhibits rubber/glass transition behaviour following heating (in a DSC pan) to 180‡C.
Proper understanding of sorption behaviour of the materials is important from the point of view of fundamental research and technology as well for applied building technology. In this paper a simple method is presented for measuring water sorption capability of solid bodies. Moisture sorption and desorption measurements were carried out on soil samples by using climatic chamber. After drying the samples in a Venticell 111 type drying equipment they were treated with a Climacell 111 type climate chamber, where the relative humidity (RH) was varied from 40 to 83% at 22°C for different times (40, 80, 120 and 240 minutes). The samples reached the equilibrium moisture content after 120 minutes for sorption. The desorption isotherm measurements were carried out at 22°C for 80 minutes of exposure at constant RH. At this point hysteresis phenomenon was observed. Besides the moisture content figures the time evolution of the damping process is also presented in this paper.
Authors:M. Marečić, F. Jović, V. Kosar, and V. Tomašić
This work deals with the photocatalytic oxidation of toluene at room temperature and atmospheric pressure in the gas phase. The differential equations of the reactor model are solved numerically with simultaneous estimation of the model parameters. Estimation of the kinetic data is performed using a modified differential method of data analysis and a Nelder–Mead method of nonlinear optimization for parameter estimation. The reaction is performed in an annular photoreactor using UVA black light blue fluorescent lamp. The experiments are carried out at different total flow rates of the reaction feed (20–160 cm3 min−1), two different inlet concentrations of toluene (2.67 and 5.24 g m−3) and at constant relative humidity (25%). A good agreement between the experimental data and theoretical predictions is obtained, supporting the applicability of the proposed models to describe the investigated process performed in laboratory annular photoreactor.
Authors:L. Barral, J. Cano, A. J. López, J. López, P. Nogueira, and C. Ramírez
The diffusive and dynamic mechanical behavior of the DGEBA/1,3-BAC epoxy resin system was studied during water absorption. The diffusion of water was investigated at 100% relative humidity, by immersion of specimens in water at 60, 80 and 100°C. In all absorption experiments, water diffusion followed Fick's law. Diffusion coefficients and saturated water concentrations are given for these temperatures. The activation energy for diffusion was determined from the relationship between the diffusion coefficient and the reciprocal of the absolute temperature. The value obtained was 31.2 kJ mol−1. Dynamic mechanical analysis of samples immersed in 100°C water and with various water contents showed both a shift of Tg, defined by thetanδ peak, to lower temperatures and a slight decrease in the dynamic modulus in the presence of water. These effects are probably a result of plasticization.
Authors:Pavel Soudek, Lubor Kalousek, and Antonín Žák
This paper is focused on hygrothermal assessment of the eave overhang detail in above-rafter placed thermal insulation roof system. Results of the long-term measurement of this detail performed on a real building as well as the testing of the measuring method are presented in this paper. Within this measurement the moisture of wooden elements performing an eave overhang of the roof was monitored primarily in order to verify their long-term functionality. In addition the temperature and relative humidity in the roof structure were measured as well. As part of this measurement, various design variants of above mentioned detail in combination with different compositions of the roof structure were compared. The long-term functionality of the assessed details is evaluated in the conclusion of this paper, taking into account especially hygrothermal status of wooden element, which is associated with threats of infestation of these elements by wood decaying fungi or insects.
Main aim of this paper is to illustrate the experimental partial results of a study on various exterior wall fragments. The study was performed for selected wall fragments and time periods, with attention focused also on wall orientation (East and South) with identical layering and also on dynamic thermal parameters connected to the thermal comfort during summer and winter. Evaluation is done for real measured climate conditions in the area of experimental laboratory (exterior – University of Zilina) and interior conditions set according to the Slovak standard. For needs of the long-term experiment (since March 2017), temperature and relative humidity between layers are monitored. This paper deals specifically with the temperature measurement of selected days. For future publications also coupled heat-air-moisture transport analysis is intended. In this part of analysis, some extreme boundary conditions were selected and reviewed from the point of view of measured temperature inside the wall. Temperature peaks are characterized with respect to exposure to real atmospheric conditions.