scholarly journals The Mladotice Lake, western Czechia: The unique genesis and evolution of the lake basin

Geografie ◽  
2010 ◽  
Vol 115 (3) ◽  
pp. 247-265 ◽  
Author(s):  
Bohumír Janský ◽  
Achim Schulte ◽  
Julius Česák ◽  
Vanessa Rios Escobar

The Mladotice Lake is a lake of unique genetic type in Czechia. In May 1872 a landslide as a result an extreme rainfall event occurred in western Czechia, blocking the Mladotický stream valley and creating the Mladotice Lake. The 1952 and 1975 air images document that collective farming had a great impact on the lake basin evolution when balks and field terraces were removed and fields were made much larger. Because of this change in land use we expected higher soil erosion and a related increase in the sedimentation rate. First bathymetric measurements of the newly created lake were carried out in 1972 and were repeated in 1999 and in 2003. Our analysis of the sedimentary record aims to identify the sediment stratigraphy, its basic physical and chemical properties, isotope content and thin sections yield a detailed temporal resolution of the sedimentation chronology. In some areas a sediment thickness of 4 m was detected. Hence, the average sedimentation rate is from 2.2 to 2.7 cm per year.

Geografie ◽  
2005 ◽  
Vol 110 (3) ◽  
pp. 210-228
Author(s):  
Tomáš Hrdinka

Anthropogenic lakes constitute one of the most significant genetic groups of lakes in Czechia. The water quality of these lakes formed through flooding of mined-out pits can be influenced by a number of factors such as physical and chemical properties of exploited rock, characteristics of the mine surroundings, secondary anthropogenic interference and time elapsed since their flooding. The quality of water determines their potential utilization, such as in water supply, agriculture, industry, recreation, nature preservation, etc. This article compares five anthropogenic lakes in mining pits after exploitation of different kind of rocks and on the basis of lake basin characteristics and physical and chemical analysis of water formulates the possibilities of their potential utilization in the context of the local landscape.


Minerals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 499 ◽  
Author(s):  
Xi Liu ◽  
Zhaoyang Sui ◽  
Hongzhan Fei ◽  
Wei Yan ◽  
Yunlu Ma ◽  
...  

Three batches of Mg2SiO4-ringwoodites (Mg-Rw) with different water contents (CH2O = ~1019(238), 5500(229) and 16,307(1219) ppm) were synthesized by using conventional high-P experimental techniques. Thirteen thin sections with different thicknesses (~14–113 μm) were prepared from them and examined for water-related IR peaks using unpolarized infrared spectra at ambient P-T conditions, leading to the observation of 15 IR peaks at ~3682, 3407, 3348, 3278, 3100, 2849, 2660, 2556, 2448, 1352, 1347, 1307, 1282, 1194 and 1186 cm−1. These IR peaks suggest multiple types of hydrogen defects in hydrous Mg-Rw. We have attributed the IR peaks at ~3680, 3650–3000 and 3000–2000 cm−1, respectively, to the hydrogen defects [VSi(OH)4], [VMg(OH)2MgSiSiMg] and [VMg(OH)2]. Combining these IR features with the chemical characteristics of hydrous Rw, we have revealed that the hydrogen defects [VMg(OH)2MgSiSiMg] are dominant in hydrous Rw at high P-T conditions, and the defects [VSi(OH)4] and [VMg(OH)2] play negligible roles. Extensive IR measurements were performed on seven thin sections annealed for several times at T of 200–600 °C and quickly quenched to room T. They display many significant variations, including an absorption enhancement of the peak at ~3680 cm−1, two new peaks occurring at ~3510 and 3461 cm−1, remarkable intensifications of the peaks at ~3405 and 3345 cm−1 and significant absorption reductions of the peaks at ~2500 cm−1. These phenomena imply significant hydrogen migration among different crystallographic sites and rearrangement of the O-H dipoles in hydrous Mg-Rw at high T. From the IR spectra obtained for hydrous Rw both unannealed and annealed at high T, we further infer that substantial amounts of cation disorder should be present in hydrous Rw at the P-T conditions of the mantle transition zone, as required by the formation of the hydrogen defects [VMg(OH)2MgSiSiMg]. The Mg-Si disorder may have very large effects on the physical and chemical properties of Rw, as exampled by its disproportional effects on the unit-cell volume and thermal expansivity.


2018 ◽  
Vol 484 (1) ◽  
pp. 165-187 ◽  
Author(s):  
Jim Buckman ◽  
Carol Mahoney ◽  
Shereef Bankole ◽  
Gary Couples ◽  
Helen Lewis ◽  
...  

AbstractMudrocks are highly heterogeneous in a range of physical and chemical properties, including: porosity and permeability, fissility, colour, particle composition, size, orientation, carbon loading, degree of compaction, and diagenetic overprint. It is therefore important that the maximum information be extracted as efficiently and completely as possible. This can be accomplished through high-resolution analysis of polished thin sections by scanning electron microscopy (SEM), with the collection of large-area images and X-ray elemental map montages, and the application of targeted particle analysis. A workflow model, based on these techniques, for the digitization of mudrocks is presented herein. A range of the data that can be collected and the variety of analyses that can be achieved are also illustrated. Data collection is discussed in terms of inherent problems with acquisition, storage, transfer and manipulation, which can be time-consuming and non-trivial. Similar information and resolutions can be achieved through other techniques, such as QEMSCAN and infra-red (IR)/Raman spectroscopic mapping. These can be seen as complementary to the workflow described herein.


2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Agata Mikolajczyk ◽  
Tanja Khosrawipour ◽  
Alice Martino ◽  
Joanna Kulas ◽  
Marek Pieczka ◽  
...  

Introduction. Micro- and nanoparticles, with their submicron size, the versatility of physical and chemical properties, and easily modifiable surface, are uniquely positioned to bypass the body’s clearing systems. Nonetheless, two main problems with micro- and nanoparticles arise which limit the intraperitoneal application. The study was performed to evaluate whether HIUS enables the imprinting of microparticles and, therefore, enhances penetration and local endurance in the peritoneum. Methods. High-intensity ultrasound (HIUS) at 20 kilohertz with an output power of 70 W was applied on peritoneal tissue samples from fresh postmortem swine for different time intervals. Before the HIUS application, the surface of the samples was covered with strontium aluminate microparticles before analysis via electron microscopy. In-tissue strontium aluminate penetration and particle distribution size were measured using fluorescence microscopy on frozen thin sections. Results. With increasing HIUS durations (1 versus 5 minutes), increasing strontium aluminate particles were detected in the peritoneum. HIUS leads to a particle selection process with enhancing predominantly the penetration of smaller particles whereas larger particles had a harder time penetrating the peritoneum. Smaller particles were detected up to 277 µm ± 86 µm into the peritoneum. Conclusion. Our data indicate that HIUS might be used as a method to prepare the peritoneal tissue for micro- and nanoparticles. Higher tissue penetration rates without the increase and longer local endurance of the applied substance could be reached. More studies need to be performed to analyze the effect of HIUS in enhancing intraperitoneal drug applications.


1997 ◽  
Vol 3 (3) ◽  
pp. 253-268 ◽  
Author(s):  
S. Pavía Santamaría ◽  
J. R. Bolton

Abstract The physical and chemical properties of bedding and pointing mortars have a major influence on the nature, rate and extent of decay of pointed stonework. Specially designed mortars can prevent physical damage and greatly reduce chemical and biological decay in both the mortars themselves and the adjacent stones. This study describes the physical and chemico-mineralogical changes that occur in a number of different stone-mortar combinations. Three types of mortar were designed and fabricated in the laboratory in accordance with [1,2]. These were examined in combination with Leinster granite, Portland limestone and Baumberger sandstone by exposing standard samples comprised of two pieces of stone 5 cm χ 5 cm χ 5 cm separated by a 5 mm mortar filled joint to artificial ageing tests in a chamber. Thin sections were examined to determine what changes had taken place in the stone and the mortar. The physical properties of the stones and mortars were determined separately. The lime mortar, though chemically well matched with the limestone and sandstone, proved to be unsuitable because of loss of cohesion. The resultant microcracking, detected by pétrographie microscope, appeared to be caused by shrinkage during drying rather than by carbonation or cycling-alteration processes. Granite-lime mortar combinations showed low adherence and decreased durability of the mortar. This effect may be the result of the greatly differing physical properties of the lime mix and granite. The ageing tests revealed a high durability in the cement mixes. The study demonstrated the suitability of cement content mortars with poorly sorted aggregate and plasticiser for bedding and pointing in granite stonework. They also illustrated the need for care with the design of lime mortar mixes to ensure adequate binder-aggregate adhesion.


1966 ◽  
Vol 24 ◽  
pp. 101-110
Author(s):  
W. Iwanowska

In connection with the spectrophotometric study of population-type characteristics of various kinds of stars, a statistical analysis of kinematical and distribution parameters of the same stars is performed at the Toruń Observatory. This has a twofold purpose: first, to provide a practical guide in selecting stars for observing programmes, second, to contribute to the understanding of relations existing between the physical and chemical properties of stars and their kinematics and distribution in the Galaxy.


Author(s):  
Sydney S. Breese ◽  
Howard L. Bachrach

Continuing studies on the physical and chemical properties of foot-and-mouth disease virus (FMDV) have included electron microscopy of RNA strands released when highly purified virus (1) was dialyzed against demlneralized distilled water. The RNA strands were dried on formvar-carbon coated electron microscope screens pretreated with 0.1% bovine plasma albumin in distilled water. At this low salt concentration the RNA strands were extended and were stained with 1% phosphotungstic acid. Random dispersions of strands were recorded on electron micrographs, enlarged to 30,000 or 40,000 X and the lengths measured with a map-measuring wheel. Figure 1 is a typical micrograph and Fig. 2 shows the distributions of strand lengths for the three major types of FMDV (A119 of 6/9/72; C3-Rezende of 1/5/73; and O1-Brugge of 8/24/73.


Author(s):  
Mehmet Sarikaya ◽  
Ilhan A. Aksay

Biomimetics involves investigation of structure, function, and methods of synthesis of biological composite materials. The goal is to apply this information to the design and synthesis of materials for engineering applications.Properties of engineering materials are structure sensitive through the whole spectrum of dimensions from nanometer to macro scale. The goal in designing and processing of technological materials, therefore, is to control microstructural evolution at each of these dimensions so as to achieve predictable physical and chemical properties. Control at each successive level of dimension, however, is a major challenge as is the retention of integrity between successive levels. Engineering materials are rarely fabricated to achieve more than a few of the desired properties and the synthesis techniques usually involve high temperature or low pressure conditions that are energy inefficient and environmentally damaging.In contrast to human-made materials, organisms synthesize composites whose intricate structures are more controlled at each scale and hierarchical order.


2017 ◽  
pp. 31-43
Author(s):  
Berta Ratilla ◽  
Loreme Cagande ◽  
Othello Capuno

Organic farming is one of the management strategies that improve productivity of marginal uplands. The study aimed to: (1) evaluate effects of various organic-based fertilizers on the growth and yield of corn; (2) determine the appropriate combination for optimum yield; and (3) assess changes on the soil physical and chemical properties. Experiment was laid out in Randomized Complete Block Design, with 3 replications and 7 treatments, namely; T0=(0-0-0); T1=1t ha-1 Evans + 45-30-30kg N, P2O5, K2O ha-1; T2=t ha-1 Wellgrow + 45-30-30kg N, P2O5, K2O ha-1; T3=15t ha-1 chicken dung; T4=10t ha-1 chicken dung + 45-30-30kg N, P2O5, K2O ha-1; T5=15t ha-1 Vermicast; and T6=10t ha-1 Vermicast + 45-30-30kg N, P2O5, K2O ha-1. Application of organic-based fertilizers with or without inorganic fertilizers promoted growth of corn than the control. But due to high infestation of corn silk beetle(Monolepta bifasciata Horns), its grain yield was greatly affected. In the second cropping, except for Evans, any of these fertilizers applied alone or combined with 45-30-30kg N, P2O5, K2O ha-1 appeared appropriate in increasing corn earyield. Soil physical and chemical properties changed with addition of organic fertilizers. While bulk density decreased irrespective of treatments, pH, total N, available P and exchangeable K generally increased more with chicken dung application.


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