Critical points in the analysis of membrane pore structures by thermoporometry

Several ultrafiltration membranes of the anisotropic and isotropic type were characterized by means of the thermoporometry. Successive cooling and heating runs were performed in order to investigate the effects of the water-ice and ice-water phase transitions on the structure of the membranes. The results found for membranes having different casting thicknesses indicate that, in some cases, pores in the sublayer of anisotropic UF membranes frustrate the measurement of the, for the separation, relevant porse present in the top layer

Permporometry: the determination of the size distribution of active pores in UF membranes

Permporometry is a method by which the characteristics of the interconnecting 'active' pores of an ultrafiltration membrane can be measured. It is these active' pores that are responsible for the actual membrane performence. Application of permporometry on different membrane types, including ceramic as well as polymeric membranes, shows that the method can provide objective information on the `active¿ pore size present

A new method to determine the skin thickness of asymmetric UF-membranes using colloidal gold particles

In this paper a new method is presented for the determination of the skin thickness of asymmetric ultrafiltration membranes. The method is based on the use of well-defined, uniformly sized colloidal gold particles, permeated from the sublayer side of the membrane, combined with electron microscopic analysis of the membrane afterward. Using this method poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) and polysulfone (PSf) membranes were investigated. PPO membranes appeared to have a well-defined skin layer with a thickness of about 0.2 μm and a pore size distinctly different from that in the macroporous layer underneath. In the case of PSf such a distinct skin layer cannot be defined. The size of the pores in these membranes gradually increases from skin to sublayer

Establishment of the Alfalfa Weevil Parasite \u3ci\u3eMicroctonus Aethiopoides (Hymenoptera: Braconidae)\u3c/i\u3e in Michigan

Microctonus aethiopoides, a braconid parasite of adult alfalfa weevil, Hypera postica, is now established in southeastern Minnesota. Releases were made near Caledonia in Houston County, in 1978 and 1979, and near Rosemount in Dakota County, in 1979 and 1980. M. aethiopoides was recovered in Houston County in 1979, a new state record, and since has expanded its range more than 40 km from the release site. Establishment in Dakota County was unexpected because of low host densities, but parasites were recovered there in 1983. Other workers have recovered M. aethiopoides in Olmstead County

The control of PVY in Dutch seed potato culture

Over the recent years Potato virus Y presents a growing problem in Dutch seed potato culture. In recent years a significant % of seed potato lots was de-classified due to PVY infections. This apparent increase in PVY infections was unexpected since no increase in field symptoms were observed and the numbers of aphids caught in the yellow water traps and high suction traps showed a clear decline over the last 10 years http://www.aab.org.uk/images/VIRO_CONF_PROG.pd

Gravity gradiometer system for Earth Exploration

We develop a gravity gradiometer (GG) for use on planetary missions to planets like Mars and Jupiter. With some modifications this development is extended to include (airborne) applications for the Dutch exploratory industry. We adapt key technology of the space based GG for the use in an environment with considerable acceleration noise. The major benefit is the considerable decrease in weight and size with the presently used gradiometer systems

Does conversion to conservation tillage really increase soil organic carbon stocks in organic arable farming?

Aggravation of weather extremes increases awareness of climate change consequences. Mitigation options are in demand which aim to reduce the atmospheric concentration of greenhouse gases. Amongst others, conversion from ploughing to conservation tillage is argued to increase soil organic carbon (SOC) stocks. Yet, main findings of reviews and meta-analyses comparing SOC stocks between tillage systems show different results: from a significant increase of SOC stocks to the question if there is any effect at all. Reasons are a sampling bias as in many campaigns only topsoil layers are assessed and horizons thickness is not considered adequately, different methods for SOC and bulk density determination, and the comparison of SOC stocks based on equivalent soil masses instead of equal sampling depths. In order to address these limitations, we initiated the SOCORT consortium (Soil Organic Carbon in Organic Reduced Tillage) – an international network of nine agronomical long-term trials. All trials represent common mixed organic farming systems of the respective region with organic fertilisation and crop rotations including leys. Climatic conditions are similar, but age and soil texture vary (7 to 21 years and sandy to clayey soils). A common sampling campaign was consequently elaborated to answer the question if the combination of conservation tillage and organic farming can really increase SOC stocks. Undisturbed soil cores were taken with driving hammer probes (8 cm in diameter) to a maximum depth of 100 cm. Each core was divided in the increments 0-30, 30-50, 50-70, 70-100 cm. The topsoil layer (0-30 cm) was further divided into the different tillage depths of the respective trial. All samples were analysed in the same laboratory for bulk density, organic carbon content, pH and texture. We compiled the yields for each trial to assess carbon inputs. The SOCORT consortium in combination with the common sampling campaign will entangle the driving factors of carbon sequestration through reduced tillage and add important knowledge on carbon dynamics in agro-ecosystems

Институт правовой охраны земель Российской Федерации, как предмет сравнительно-правового анализа земельно-правового регулирования в странах СНГ

У статті автором проведено порівняльно-правовий аналіз інституту правової охорони земель у країнах СНД на прикладі Росії. Ключові слова: oхорона земель, охорона земель Російської Федерації, землекористування, охорона навколишнього середовища, деградація, консервація землі.В данной статье отображена попытка автора провести сравнительно-правовой анализ института правовой охраны земель в странах СНГ на примере Российской Федерации и Украины. Ключевые слова: oхрана земель, охрана земель Российской Федерации, землепользование, охрана окружающей среды, деградация, консервация земли.The attempt of author to conduct the comparative-legal analysis of institute of legal safeguard of earths in the countries of the CIS on the example of Russian Federation and Ukraine is represented in this article. Key words: land’s preservation, Russian Federation’s land preservation, land tenure, preservation of the environment, land’s degeneration, land’s conservation

Nonlinearities and Effects of Transverse Beam Size in Beam Position Monitors (revised)

The fields produced by a long beam with a given transverse charge distribution in a homogeneous vacuum chamber are studied. Signals induced by a displaced finite-size beam on electrodes of a beam position monitor (BPM) are calculated and compared to those produced by a pencil beam. The non-linearities and corrections to BPM signals due to a finite transverse beam size are calculated for an arbitrary chamber cross section. Simple analytical expressions are given for a few particular transverse distributions of the beam current in a circular or rectangular chamber. Of particular interest is a general proof that in an arbitrary homogeneous chamber the beam-size corrections vanish for any axisymmetric beam current distribution.Comment: REVTeX, 8 pages, 9 figures. Corrected Eqs. (7),(22),(25) and Figs. 2-9. Expande