Evaluation of surface smoothness using a light-sectioning shadow scanner

A new type of sensor for rapid three-dimensional evaluation of surface geometrical properties is presented. Light emitted with a fixed small angle to the surface plane by a projector is directed into the measured surface. A curtain installed in the light path close to the surface creates a shadow on the measured surface. The shape of the border between bright (highly lit area) and dark (shadow area) is a profile section of the surface. The camera installed over the measured surface captures an image of the border and a digital signal processor using image analysis techniques digitizes the profile section. The shadow scanner method evaluated here could be used for rapid and accurate scans of surfaces of various porous materials, particularly wood, veneer, paper, fiberboards, leaves, and similar materials in both laboratory and industrial applications. The simplicity of the sensor is an advantage because it makes the system easy to maintain, resistant to breakage, and inexpensive. Its straightforward nature and high accuracy enables the method to be utilized for on-line measurement, and therefore it is suitable for industrial application.     

Temporal and spatial variability of enantiomeric fractions (EFs) of chiral organochlorines in relation to soil properties

Purpose

The scope of this article was to investigate the spatial and temporal variability of enantiomeric fractions (EFs) of persistent organic pollutants (POPs) in soil compared to the uncertainty of the analytical data.

Materials and methods

Soil samples were taken with high spatial resolution at two sites in Czech Republic in 2008 to investigate variability on a small spatial scale. In addition, composite soil samples were taken from ten sites in 2005 and 2008 to investigate temporal variations. All samples were analysed for a suite of soil properties as well as concentrations and EFs of polychlorinated biphenyl (PCB) -95, PCB-132 and PCB-149; α-hexachlorocyclohexane (HCH); o,p′-dichlorodiphenyltrichloroethane (DDT); and o,p′-dichlorodiphenyldichloroethane (DDD).

Results and discussion

Median EFs of PCB-95 and PCB-149, α-HCH, o,p′-DDT and o,p′-DDD did not change significantly on the sites sampled in 2005 and again in 2008, while PCB-132 changed from EF?=?0.38 to EF?=?0.53. The sampling methodology is therefore very important, and composite samples will not be the best option if enantioselective degradation processes are investigated. Non-racemic EFs of POPs in the subsampled sites in 2008 were correlated to soil parameters, such as total organic carbon (TOC), total nitrogen and humic acids. These parameters are site specific and might vary on a small scale. This can explain why certain soil parameters are reported as significantly correlated with non-racemic EFs of chiral POPs in some studies, but not always in other similar studies.

Conclusions

While composite samples may still represent the overall prevailing EF range, they are not ideally suited to study enantiomeric degradation processes, which are taking place at a relative small scale, depending on the heterogeneity of soil parameters such as TOC, total organic nitrogen (TON) and humic acids.

     

In situ weathering of rocks or aeolian silt deposition: key parameters for verifying parent material and pedogenesis in the Opawskie Mountains—a case study from SW Poland

Purpose

The aims: (1) to investigate the role of the in situ weathering of bedrock in providing substrate for soil formation; (2) to evaluate the aeolian contribution to the mountainous soils in the vicinity of thick loess cover; and (3) to determine the influence of aeolian silt on further soil development.

Materials and methods

The sampled sites were arranged along the slope toposequence, where an aeolian/silt admixture possibly occurred. Each soil catena started at the top of a hill and ended at its foot. Such an arrangement of the soil profiles ensured the tracking of loess thickness variations and detection of the depth of the residuum-derived materials. One reference soil profile, consisting of aeolian silt deposits, was made. The following soil properties were determined: pH, organic carbon content, soil texture, exchangeable acidity, exchangeable ions and geochemistry. In addition, thin sections were prepared from rock samples to confirm the type of bedrock present.

Results and discussion

The soils in the studied area were classified as Cambisols, Luvisols and Stagnosols, characterised by silt loam texture and a high content of elements indicating an aeolian silt contribution—Hf (7.4 to 14.8 ppm) and Zr (274.4 to 549.0 ppm). These values differ strongly from the residues typical of weathered quartzite, greywacke or catalasite substrates, which generally have low concentrations of Hf and Zr (0.7 to 7.0 ppm and 26.0 to 263 ppm, respectively). Based on the morphological, textural and geochemical data of the studied soils, three layers were distinguished, which show different inputs of aeolian silt: (1) an aeolian silt mantle; (2) a mixed zone in which loess was incorporated into the local material; and (3) a basal zone, free of the influence of aeolian silt. Based on the obtained results, a hypothetical pathway for soil formation in mountainous areas, influenced by aeolian silt admixing, was proposed.

Conclusions

Our study demonstrates that the soils developed in the Opawskie Mountains are characterised by an aeolian silt influence. This differentiates them from weakly developed soils, which comprise materials formed during in situ weathering only. Materials originating from bedrock weathering did not play an independent role as the parent material for the studied pedons. Aeolian silt was admixed with already existing autochthonous substrates, or completely replaced them. This influence on the soil formation resulted in the occurrence of Luvisols, Stagnosols and Cambisols. Such soils cannot be formed from the weathering of quartzites and greywackes, which contribute to a less structure-forming medium.

     

Contrasting influences of inundation and land use on the rate of floodplain restoration

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Movements of small mammals in the heterogeneous landscape

Distances and directions of Apodemus agrarius and Clethrionomus glareolus movements were studied using snap traps and colored bait. The longest distances traversed exceeded 1500 m. Some directions of movement were significantly more common. High variability in the number of captures along traplines suggests distinct movement routes. Small mammals appear to base their movement on the landscape and not on individual biotopes.     

Adsorption Kinetics of Acid Red on Activated Carbon Web Prepared from Acrylic Fibrous Waste

In this work, activated carbon (AC) web was prepared using physical activation under the layer of charcoal in high temperature furnace. The carbonization of acrylic fibrous waste was performed at different temperatures (800 °C, 1000 °C, and 1200 °C) with heating rate of 300 °C/h and at different holding time. At 1200 °C, the heating rate of 300 °C/h and no holding time provided better results of surface area as compared to carbonization at 800 °C and 1000 °C. The activated carbon web (AC) prepared at 1200 °C was used for removal of Acid Red 27 dye from aqueous media by varying different parameters like initial concentration of dye, stirring speed, adsorbent dosage, and pH. The results were evaluated using non-linear forms of Langmuir and Freundlich isotherms. The Freundlich isotherm was found to describe the results more effectively because of non-homogenous surface of activated carbon web. Further, the kinetics of adsorption was examined using linear and nonlinear forms of pseudo 1st order and pseudo 2nd order.     

Evaluation of suspended load changes using AnnAGNPS and SWAT semi-empirical erosion models

Simulation models are frequently used tools for suspended sediment load quantification in mesoscale catchment areas. To improve the simulation results, it is important to compare and verify different models using measured data. In this study, we tested two continuous simulation, semi-distributed erosion and sediment transport models AnnAGNPS and SWAT for the period of 1995–2004 in the Blšanka river basin. The catchment (374 km²) is an agricultural hop-growing region in the north-western part of the Czech Republic. Both models were calibrated using the first 5 years of data, and then validated using the second 5 years of daily discharge and suspended sediment yield values. For the long-term continuous simulation, the results of SWAT model simulation showed a better agreement to the measured data, while for short-term rainfall-runoff event simulation, especially short duration intensive rainfall events, suspended load was more accurately predicted by AnnAGNPS. Land use changed significantly in parts of the river basin during the observation period. Many hop-gardens were dismantled and arable land was partially converted to grassland and pasture. This enabled us to test the applicability of AnnAGNPS and SWAT models under changing land use conditions. According to both models, suspended sediment load was reduced after the land use changes by 10%–30%, which was in agreement with decreasing sediment discharge observed at the watershed outlet.     

The carbon dioxide laser: an alternative surgery technique for the treatment of common cutaneous tumors in dogs

Background

Tumors of the skin and subcutaneous tissue are the largest group of canine neoplasms. Total excision is still the most effective method for treatment of these skin tumors. For its universal properties the carbon dioxide (CO₂) laser appears to be an excellent surgical instrument in veterinary surgery. Laser techniques are alternatives to traditional methods for the surgical management of tumors. The aim of this study was to compare various types of laser techniques in skin oncologic surgery: excision, ablation and mixed technique and to suggest which technique of CO₂ laser procedure is the most useful in particular case of tumors in dogs.

Findings

The study was performed on 38 privately-owned dogs with total number of 40 skin tumors of different type removed by various CO₂ laser operation techniques from 2010–2013. The treatment effect was based on the surgical wound evaluation, the relative time of healing and possible local recurrence of the tumor after 3 months post surgery. Local recurrence was observed in two cases. The study showed that in 30 cases time needed for complete resection of lesions was less than 10 minutes. Time of healing was longer than 12 days in 6 cases (42.8%) with tumor excision and in 14 cases (87.5%) where excision with ablation technique was performed.

Conclusions

The advantages of the CO₂ laser surgery were better hemostasis, precision of working, non-contact dissection, less instruments at the site of operation and minimum traumatization of the surrounding tissues.     

Silicon device scaling to the sub-10-nm regime

In the next decade, advances in complementary metal-oxide semiconductor fabrication will lead to devices with gate lengths (the region in the device that switches the current flow on and off) below 10 nanometers (nm), as compared with current gate lengths in chips that are now about 50 nm. However, conventional scaling will no longer be sufficient to continue device performance by creating smaller transistors. Alternatives that are being pursued include new device geometries such as ultrathin channel structures to control capacitive losses and multiple gates to better control leakage pathways. Improvement in device speed by enhancing the mobility of charge carriers may be obtained with strain engineering and the use of different crystal orientations. Here, we discuss challenges and possible solutions for continued silicon device performance trends down to the sub-10-nm gate regimes.