15 research outputs found
A study of incremental sheet forming by using water jet
In this work, a variant of the incremental sheet forming (ISF) process, namely the incremental sheet forming by using water jet (ISF-WJ), was studied. In the investigation, an ISF-WJ prototype machine was designed and developed. Different design concepts of the water jet nozzle were proposed and evaluated to achieve the maximum forming pressure by performing computational fluid dynamic (CFD) simulations. Based on the forming pressure distribution modeled by CFD simulations, finite element (FE) models were developed to study the sheet deformation behavior under the ISF-WJ process condition. Based on the understanding gained from the numerical study, experiments were conducted to validate the ISF-WJ process and the developed prototype machine. The results suggest that ISF-WJ is a feasible process to achieve improved surface finish of thin sheet parts. In addition, this study has found that water jet pressure plays an important role in preventing sheet wrinkling and obtaining an accurate geometry of formed parts
Predicting the outcomes of organic reactions via machine learning: are current descriptors sufficient?
As machine learning/artificial intelligence algorithms are defeating chess masters and, most recently, GO champions, there is interest -and hope -that they will prove equally useful in assisting chemists in predicting outcomes of organic reactions. This paper demonstrates, however, that the applicability of machine learning to the problems of chemical reactivity over diverse types of chemistries remains limited -in particular, with the currently available chemical descriptors, fundamental mathematical theorems impose upper bounds on the accuracy with which raction yields and times can be predicted. Improving the performance of machine-learning methods calls for the development of fundamentally new chemical descriptors
Distribution of chemical elements in attic dust and soil as reflection of lithology and anthropogenic influence in Slovenia
The aim of this study was to establish contents and distribution of chemical elements in attic dust in
Slovenia, and to define them according to geology and anthiopogenic influence. Attic dust and topsoil (0-5 cm)
samples were collected in the rural area in settlements without known industry and in six largest towns in Slovenia.
Analysis of 42 chemical elements was performed. For estimation of the association between elements and sampling
materials the R mode factor analysis was applied. Al, Ba, Co, Ci, Fe, La, Mn, Na, Nb, Ni, Sc, Th, Ti, Y, V and Zr
in attic dust reflect the natural distribution. The highest elemental contents in attic dust occur in the areas of igneous
and metmoiphic rocks and of flysch formation. High contents of the elemental association Co, Ci, Fe, Mn, and Ni
reflect also centuries of ferrous metallurgy. Distribution of As, Cd, Cu, Hg, Mo, Sb, Sn, Sr, Pb and Zn represents
the anthropogenically introduced chemical elements. Their averages in attic dust are higher compared to topsoil.
High contents of these elements are a result of historical Pb-Zn mining and smelting
Geochemical soil and attic dust survey in Idrija, Slovenia
By sampling of soil and attic dust in an area of 160 km around the Idrija mercury mine it was established
that mercury concentrations in soil exceed the critical values for soil (10 mg/kg) on 19 km. The weighted mercury
mean for the studied area is 1.3 mg/kg (0.26-973 mg/kg) for soil and 9.7 mg/kg (0.58-1055 mg/kg) for attic dust.
The highest ratios between Hg abundances in dust versus soil were found in the most distant localities and on higher
altitudes above the sea level. Hg in soil exceeds Hg in attic dust only in localities in which the sources of the metal
are tailings or rocks next to atmospheric emission
Distribution of some natural and man-made radionuclides in soil from the city of Veles (Republic of Macedonia) and its environs
An Approach to Determine Pressure Profile Generated by Compression Bandage Using Quasi-Linear Viscoelastic Model
Важность аллотигенных акцессорных микроэлементов в матрице факторных нагрузок как статистическое выражение геохимической изменчивости почв различного возраста
Comparison of Image Enhancement Methods for the Effective Diagnosis in Successive Whole-Body Bone Scans
Whole-body bone scan is one of the most frequent diagnostic procedures in nuclear medicine. Especially, it plays a significant role in important procedures such as the diagnosis of osseous metastasis and evaluation of osseous tumor response to chemotherapy and radiation therapy. It can also be used to monitor the possibility of any recurrence of the tumor. However, it is a very time-consuming effort for radiologists to quantify subtle interval changes between successive whole-body bone scans because of many variations such as intensity, geometry, and morphology. In this paper, we present the most effective method of image enhancement based on histograms, which may assist radiologists in interpreting successive whole-body bone scans effectively. Forty-eight successive whole-body bone scans from 10 patients were obtained and evaluated using six methods of image enhancement based on histograms: histogram equalization, brightness-preserving bi-histogram equalization, contrast-limited adaptive histogram equalization, end-in search, histogram matching, and exact histogram matching (EHM). Comparison of the results of the different methods was made using three similarity measures peak signal-to-noise ratio, histogram intersection, and structural similarity. Image enhancement of successive bone scans using EHM showed the best results out of the six methods measured for all similarity measures. EHM is the best method of image enhancement based on histograms for diagnosing successive whole-body bone scans. The method for successive whole-body bone scans has the potential to greatly assist radiologists quantify interval changes more accurately and quickly by compensating for the variable nature of intensity information. Consequently, it can improve radiologists’ diagnostic accuracy as well as reduce reading time for detecting interval changes
Integrating nowcasting with crisis management and risk prevention in a transnational and interdisciplinary framework
This paper presents the recent WWRP/WMO Forecast Demonstration Project INCA-CE (INtegrating nowCAsting for Central Europe) co-funded by the European Union. Twenty-four partners of national and regional hydro-meteorological services, national and regional crisis and disaster management centers, and authorities for road management world-wide have participated in INCA-CE for international cooperation on nowcasting development, interdisciplinary cooperation for nowcasting applications and transnational cooperation for nowcasting services. INCA-CE has implemented the nowcasting system INCA at the project partner countries, applied INCA nowcasting in civil protection, operational hydrology and road safety, and improved the INCA system based on the end user's requirements. The main difference to other similar projects is that end user's involvement and the improvements involve the whole end user value chain. The project has developed several ideas for end users on how to interpret nowcasting products (INCA-SWING) and on how to deal with the nowcasting products in their working practice (INCA-MCPEX and ISW). INCA-CE is also oriented strongly to transnational cooperation in nowcasting development and implementation, in easy access to a homogenized set of nowcasting products from those INCA providers to end users in the region, and in the transnational use of real-time products by end users in cases of high impact weather across borders