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Optimizing current chemical processes alone does not yield the improvements required in the fine chemical and pharmaceutical industries. At least partially, a switch from batch to continuous manufacturing is needed. Cost-, time-, and atom-efficient routes frequently demand the application of high temperatures, pressures, and concentrations, and/or the use of highly reactive reagents. These chemistries often cannot be employed in conventional reactors. Costly and long alternative synthetic routes are chosen instead. The application of continuous-flow microreactors allows to access “harsh” or “hazardous” reaction conditions and, furthermore, enables entirely new transformations.

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The ability of Kocuria varians to grow and produce protease when utilizing various local wastes was studied. Impact of cultivation pH on growth and enzyme production was also evaluated. Cassava waste combined with bambara nut waste (1:1) gave the best protease yield. Maximum enzyme production was attained when production medium was adjusted to pH 9. Highest protease concentration in the culture fluid was recorded at 20 h during the exponential phase of growth. The enzyme was optimally active and stable at 80 °C. Optimum pH for protease activity was at 11 with optimal stability at the alkaline range (pH 7–11) after incubation for 1 h. The enzyme was inhibited by EDTA, Hg2+, and Zn2+, but not by Pb2+, and was slightly stimulated by Cu2+. The properties of this protease make it a promising candidate for further studies and possible applications in processes involving extreme conditions of pH and temperature.

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Chelatbildende Austauscherharze, VII

Chelataustauscher auf 1.8-dihydroxynaphthalin-O, O-diessigsäure-basis zur abtrennung des zirkoniums von hafnium und anderen elementen

Journal of Radioanalytical and Nuclear Chemistry
Authors: E. Blasius and G. Kynast

Abstract  

Preparation and use of a resin with 1.8-dihydroxynaphthalene-O,O-diacetic acid as chelating group are described. Besides the separation of many of the common interfering ions it also permits the separation of Hf. The following ions could be separated quantitatively: Mg(II), Pb(II), Cu(II), Fe(III), La(III), Ce(IV), Th(IV), Ti(IV), and U(VI). During these and further qualitative and quantitative experiments no interfering ions could be found. A method for the separation of95Zr from its daughter nuclide95Nb is also described. The main problem proved to be the separation of Zr(IV) and Hf(IV), owing to their close resemblance. To accomplish quantitative determination of Zr and Hf without any separation,95Zr and175+181Hf radioisotopes were used. The chelating resin permits the separation of 95% of Hf(IV) from an equimolar solution. The main part of Hf(IV) is eluated by 2M hydrochloric acid, and subsequently Zr(IV) by 0.75M oxalic acid. The rest of Hf is enriched in the first fractions of the oxalic acid eluate, so that when eliminating these, even after a single step experiment hafnium free from zirconium and a rather pure fraction of zirconium are obtained. Even under extreme conditions of concentration (Zr∶Hf=91∶1) 75% of Hf can be separated free from Zr in a single step experiment.

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Abstract  

Appreciable amounts of different arsenic compounds are used in the manufacture of glass and glass ampoules (injection vials and bottles) used to store drugs. Exposure/intake of arsenic to human beings may result in skin ulceration, injury to mucous membranes, perforation of nasal septum, skin cancer and keratoses, especially of the palms and soles and may cause detrimental effects. Considering the toxicity of arsenic, even if traces of arsenic from such glass containers/ampoules are leached out, it can impart damage to human beings. To check the possibility of leaching of arsenic from glass ampoules, a simple methodology has been developed. Different makes and varieties of glass ampoules filled with de-ionized water were subjected to high pressure and temperature leaching for varying amount of time using autoclave to create extreme conditions for the maximum leaching out of the analyte. Subsequently, the determination of the arsenic contents in leached water using neutron activation analysis is reported in this paper in detail with observations.

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Abstract  

The mechanical properties of solid rocket propellants are very important for good functioning of rocket motors. During use and storage the mechanical properties of rocket propellants are changing, due to chemical and mechanical influences such as thermal reactions, oxidation reactions or vibrations. These influences can result in malfunctioning, leading to an unwanted explosion of the rocket motor. Most of modern rocket propellants consist of a polymer matrix (i.e. HTPB) filled with a crystalline material (i.e. AP, AN). However, the more conventional double base propellants consist of a solid gel matrix with additives, such as stabilizers. Both materials show a mechanical behaviour, quite similar to that of general polymers. To describe the material behaviour of both propellants a linear visco-elastic theory is often used to describe the mechanical behaviour for small deformations. Because the time-temperature dependency is also valid for these materials a mastercurve can be constituted. With this mastercurve the response properties (stiffness) under extreme conditions can be determined. At TNO-PML a mastercurve of a double base propellant was constituted using dynamical mechanical analysis (DMA) and compared with a mastercurve reduced from conventional (static) stress relaxation tests. The mechanical properties of this double base propellant determined by DMA were compared with conventional (quasi-static) tensile test results.

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One option for adaptation to climate change is to grow a wider variety of plant species. Sorghum (Sorghum bicolor (L.) Moench) is known to tolerate unfavourable environmental conditions, so it may be feasible to grow it on areas with extreme conditions to replace other species such as maize. Nowadays, spatial decision supporting systems primarily support the crop production process rather than crop structure adjustment. In this study, potential sorghum production sites in the Great Hungarian Plain were selected based on soil characteristics including genetic soil type, parent material, physical soil type, clay composition, water management, pH, organic matter content, topsoil thickness and fertility, as well as climatic data, particularly precipitation. For all the parameters the aim was to find the extreme values at which sorghum, which is less sensitive than maize, may still give an acceptable yield. By combining map layers of soil characteristics, it could be concluded that although the soil is suitable for sorghum on 40.46% of the Great Hungarian Plain, maize is generally a better choice economically. On the other hand, the soil conditions on 0.65% of the land are still suitable for sorghum but unfavourable for maize. As regards the precipitation demand of sorghum, May is the critical period; on 698,968 ha the precipitation required for germination was only recorded once in the period 1991-2010, so these areas cannot be considererd for sorghum. As a consequence, in an alternative crop rotation system sorghum could be competitive with maize, but both the soil and climate conditions and the demands of the crop need to be assessed. The lack of precipitation in critical phenophases significantly decreases the area where maize can survive. Sorghum, however, may produce an acceptable yield, as it is a drought-resistant species.

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Agricultural utilisation is one of the most promising uses of sewage sludge in Hungary. Sewage sludge can be applied to agricultural fields in two ways: the injection of dewatered sewage sludge and the application of sewage sludge after composting. Vermicomposting is a special type of composting, where the organic residues are broken down by earthworms. The worms facilitate the decomposition process both by mixing the sludge and by physically degrading it. Earthworm species have various morphotypes requiring different habitats. Compost worms have great adaptability to extreme conditions and are capable of exploiting organic matter in a state of decomposition. Eisenia sp., Eudrilus eugeniae and Perionyx excavatus are important species for vermicomposting.

When examining the role and possibilities of vermicomposting, it is important to compare it with traditional composting methods.

The most important aspect of producing vermicompost is to ensure optimum environmental conditions for the earthworms, especially in terms of temperature, humidity and aeration, which requires constant attention.

An important feature of traditional composting is the thermophilic phase, during which the pathogenic organisms in sewage sludge are destroyed. The thermophilic phase is omitted during vermicomposting due to the thermal sensitivity of the earthworms, but the presence and activity of the earthworms results in similar sterility.

Regarding its nutrient content, vermicompost contains larger quantities of total and plant-available macroelements than conventional composts. A further advantage is the presence of the plant hormone agents excreted by earthworms.

From the environmental point of view, the ability of earthworms to accumulate heavy metals and the role of their special gut flora in the decomposition of organic pollutants could contribute to the wider use of vermicomposting to dispose of sewage sludge.

While vermicompost has many advantages, a number of obstacles need to be overcome before it can be routinely used in Hungary. Many landowners regard sewage sludge compost as hazardous waste that could contaminate their soil and crops rather than as a nutrient and soil amendment. Although numerous studies have been published on sewage sludge, the assessment of long-term effects, including the issues currently of most concern in Hungary, is still lacking.

Vermicomposting is therefore a promising, innovative technology for sewage sludge recycling. Sewage sludge and sewage sludge composts with pollutant contents greater than the limits laid down in Government Regulation 50/2001. (IV.3.) can be made suitable for agricultural use by vermicomposting.

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The V-belt drive is a rather popular, widely used form of power transmission in agricultural and food industry engineering. At the same time, its stability, the lifetime of V-belt is influenced by several environmental factors, namely in the food industry by the contamination affecting the belt sides, the ambient temperature, humidity and the occasionally aggressive (acidic, alkaline air, air saturated with gases, etc.) medium. In the case of agricultural machinery, the vibration caused by uncertainly oriented pulleys with bearing in different plate structures (often being shaken in the fields) as well as alignment adjustment inaccuracies jeopardize the reliability of the parameters of the drive. Furthermore, the efficiency is determined by several factors together: the slippage occurring during drive transmission, the hysteresis loss resulting from the external and internal friction occurring with the belt entering and exiting the pulley. Experimental equipment and calculation methods were developed to determine the dynamics of temperature increase generated by the belt and pulley relationship. The temperature generated in the V-belt was measured as a function of pretension, pulley diameter and bending frequency. The so-called damping factor characterizing the contact with the pulley (the external friction when entering and exiting the groove) and the hysteresis loss (inner friction) are also determined. On the basis of the damping factor (ζ400 Ns/m 2) of the V-belt involved in the experiments the other losses (P oth) occurring from the pulley—V-belt contact and internal friction may be estimated. The drive parameters may be optimized with the mathematical model describing the effect of the pulley diameter and belt frequency on the increase in temperature.

A standardized calculation method as well as design factors valid for the properly adjusted drive and normal operating conditions determined through empirical and laboratory experiments are used for the sizing of V-belt drives. The lifetime of V-belt drives designed in this way, used in extreme conditions typical of agricultural machinery will not be appropriate and will not provide clear, predictable information for maintenance planning. In such cases the results of our own many lifetime tests conducted in the given circumstances can be safely relied on.

The agricultural harvesting machines are large plate-body self-propelled structures on which most of the power supply of the (threshing, cleaning, moving, etc.) machine units handling the crop is realized via belt drives. The distance and angular displacement of the axes involved in the drive can vary within wide limits. The misalignment and angular displacement of the pulleys can be the result of installation instability — due to the plate structure — and the deformation of the plate structure occurring during the operation as well. V-belt drives operate satisfactorily under such conditions as well, however these faults are unfavourable in terms of belt lifetime and result in the reduction of drive efficiency.

A further aim of our research is to examine through experiments the lifetime and efficiency of V-belts used in agricultural machines as a function of drive adjustment errors. According to the results of the measurements of the geometrical adjustment errors of V-belt drives performed in the field, the pulleys of agricultural equipment are not always positioned in the medium plane of the drive. In our experiments these data served as independent variables. Figure 1 shows the arrangement of a V-belt drive in a grain harvester with the laser pulley alignment measuring instrument installed as an accessory. In the case of many machine types in 80% of the tested drives three times the permissible error was measured, and because of off-road use, due to dynamic load these errors further increased as a result of the frame deformation.

The results of both the belt bending testing and the geometrical adjustment testing of the drive offer great help in the design of belt drives. At the same time they can be the source of lifetime and efficiency forecasts.

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, B. O. and Beale , K. Ya. ( 1986 ): Adaptation of the photosynthetic device of plants of the Kara Kum Desert to extreme conditions . – Physiol. of plants, Moscow , 5 ( 33 ): 888 – 895

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Duna-Tisza közi meszes homoktalajon, az őrbottyáni kísérleti telepünkön beállított NPK műtrágyázási tartamkísérlet 26. évében, 1996-ban vizsgáltuk a műtrágyázás hatását az Orbit fajtájú tavaszi árpa fejlődésére, termésére és elemfelvételére. Termőhely talaja a főbb tápelemekben (N, P, K) gyengén ellátott, a szántott réteg 1% körüli CaCO3-ot és 1% humuszt tartalmaz. Az altalaj erősen karbonátos, az agyagos rész 5–10%. A talajvíz 8–10 m mélyen található, a terület aszályérzékeny. A műtrágyákat pétisó, szuperfoszfát és kálisó formájában alkalmaztuk. A levonható főbb tanulságok:

1. A tavaszi árpa 3,5 hónapos tenyészideje alatt mindössze 132 mm csapadékot kapott. Száraz tavaszon az állomány gyengén fejlődött, nem bokrosodott és gyorsan szárbaszökött. A m2-enkénti kalászszám 130 db volt átlagosan, az ezermag tömege pedig 30 g. A 0,3 t/ha körüli szalma és szem tömegét a bőséges NPK-trágyázás megkétszerezte, így a maximális földfeletti légszáraz biomassza 1,5 t/ha mennyiséget ért.2O5), 6 kg Mg (10 kg MgO) mennyiségnek adódott. A N és K mintegy 50%-kal, P és Ca 150–200%-kal, a Mg 500%-kal haladta meg a hazai szaktanácsadásban ajánlott irányszámokat. Az extrém körülmények között, kicsi terméssel nyert fajlagos értékek nem adhatnak reális útmutatást a tervezett termés elemigényének becslésekor.

2. A kontrollhoz viszonyítva az NP-trágyázás növelte a N és a Ca, Mg, Na, Sr kationok mennyiségét a szalmában, majd a pótlólagos K-trágyázással a kifejezett kationantagonizmus nyomán a Ca, Mg, Na, Sr elemek beépülése gátlást szenvedett. A K-Ba szinergizmust, míg a K-B elemek közötti kapcsolat antagonizmust jelzett. A kis termésben a legtöbb vizsgált elem feldúsult, az aszály töményedési effektust eredményezett a N, K, Ca, Mg, P esetében.

3. Az NP-trágyázás bizonyíthatóan serkentette a N, Ca, S, Sr, B akkumulációját a szemben. A javuló K-ellátottsággal itt is nőtt a Ba-tartalom, ill. visszaszorult az egyéb kationok felvétele. A töményedési effektus azonban nem jelentkezett a szemtermés összetételében, eltérően a szalmától.

4. A szem elsősorban a N, P, Zn, ill. részben a S és Cu elemekben dúsult. Szalma viszont 1,5–2,0-szor több K és Mg, 3–4-szer több Fe, Mn, Na, B; 10–13-szor több Ca, Ba, S, ill. 23-szor több Fe elemet halmozott fel szöveteiben a szemhez képest.

5. Az 1 t szem + a hozzátartozó melléktermés ún. fajlagos elemtartalma a kísérlet átlagában 35 kg N, 28 kg K, 12 kg Ca, 10 kg P (23 kg P2O5), 6 kg Mg (10 kg MgO) mennyiségnek adódott. A N és K mintegy 50%-kal, P és Ca 150–200%-kal, a Mg 500%-kal haladta meg a hazai szaktanácsadásban ajánlott irányszámokat. Az extrém körülmények között, kicsi terméssel nyert fajlagos értékek nem adhatnak reális útmutatást a tervezett termés elemigényének becslésekor.

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