Dimpling process in cold roll metal forming by finite element modelling and experimental validation

The dimpling process is a novel cold-roll forming process that involves dimpling of a rolled flat strip prior to the roll forming operation. This is a process undertaken to enhance the material properties and subsequent products’ structural performance while maintaining a minimum strip thickness. In order to understand the complex and interrelated nonlinear changes in contact, geometry and material properties that occur in the process, it is necessary to accurately simulate the process and validate through physical tests. In this paper, 3D non-linear finite element analysis was employed to simulate the dimpling process and mechanical testing of the subsequent dimpled sheets, in which the dimple geometry and material properties data were directly transferred from the dimpling process. Physical measurements, tensile and bending tests on dimpled sheet steel were conducted to evaluate the simulation results. Simulation of the dimpling process identified the amount of non-uniform plastic strain introduced and the manner in which this was distributed through the sheet. The plastic strain resulted in strain hardening which could correlate to the increase in the strength of the dimpled steel when compared to plain steel originating from the same coil material. A parametric study revealed that the amount of plastic strain depends upon on the process parameters such as friction and overlapping gap between the two forming rolls. The results derived from simulations of the tensile and bending tests were in good agreement with the experimental ones. The validation indicates that the finite element analysis was able to successfully simulate the dimpling process and mechanical properties of the subsequent dimpled steel products

Наноалмазы как идеальные наноносители для циансодежащих цитостатиков

Цианосодержащие цитостатики - новый класс открытых нами лекарств, которые благодаря цианогруппам хорошо закрепляются на наноалмазах, с увеличением активности

The Design and Development of New Cold Roll Formed Products by Finite Element Modeling and Optimisation

The design and development of new cold roll formed products can incur significant cost and the product may not be optimised for either performance or manufacture. This paper describes a new method to develop an optimum structural design of profile by cold roll forming using a combined approach of finite element analysis and optimisation techniques. To illustrate the concept, the design and development of a new channel beam and a new drain grating subjected to bending are presented. The two case studies, demonstrate how a roll formed profile may be optimised to improved structural performance through use of stiffeners and/or dimples. Improved performance of cold roll formed products is achieved by increasing the strength of the product without increasing the amount of the material used. The results of this paper clearly demonstrate an efficient and effective method and tool set to optimise design for performance and manufacture of cold roll formed products

Computed micro-tomographic evaluation of glide pathwith nickel-titanium rotary pathFile in maxillary firstmolars curved canals

Introduction: X-ray computed micro-tomography scanning allows high-resolution 3-dimensional imaging of small objects. In this study, micro-CT scanning was used to compare the ability of manual and mechanical glide path to maintain the original root canal anatomy. Methods: Eight extracted upper first permanent molars were scanned at the TOMOLAB station at ELETTRA Synchrotron Light Laboratory in Trieste, Italy, with a microfocus cone-beam geometry system. A total of 2,400 projections on 360 degrees have been acquired at 100 kV and 80 mu A, with a focal spot size of 8 mu m. Buccal root canals of each specimen (n = 16) were randomly assigned to Path File (P) or stainless-steel K-file (K) to perform glide path at the full working length. Specimens were then microscanned at the apical level (A) and at the point of the maximum curvature level (C) for post-treatment analyses. Curvatures of root canals were classified as moderate (= 40 degrees). The ratio of diameter ratios (RDRs) and the ratio of cross-sectional areas (RAs) were assessed. For each level of analysis (A and C), 2 balanced 2-way factorial analyses of variance (P < .05) were performed to evaluate the significance of the instrument factor and of canal curvature factor as well as the interactions of the factors both with RDRs and RAs. Results: Specimens in the K group had a mean curvature of 35.4 degrees +/- 11.5 degrees; those in the P group had a curvature of 38 degrees +/- 9.9 degrees. The instrument factor (P and K) was extremely significant (P < .001) for both the RDR and RA parameters, regardless of the point of analysis. Conclusions: Micro-CT scanning confirmed that NiTi rotary Path File instruments preserve the original canal anatomy and cause less canal aberrations. (J Endod 2012;38:389-393

Compressive Strength Tests and Design of Cold-formed Plain and Dimpled Steel Columns

This paper presents the experiments and design formulae of cold-formed plain and dimpled steel columns. A series of compression tests on plain and dimpled channel columns were conducted over a range of different geometries and the strength of the columns were investigated. The change in strength of the dimpled columns resulting from the cold working associated with the dimpling process was considered. The results showed that the buckling and ultimate strengths of dimpled steel columns were up to 33% and 26% greater than plain steel columns, respectively. The test results were evaluated by comparing buckling and ultimate loads of plain and dimpled channel columns with the values predicted by theoretical and semi-empirical methods. It was found that the predicted buckling and ultimate loads correlated well with the experimental results. Based on the experimental results, expressions for determining buckling and ultimate strengths of component plate elements of plain and dimpled channel columns were formulated

A new trans-Ionian spider species for the Italian fauna: Habrocestum graecum Dalmas, 1920 (Araneae, Salticidae)

The salticid spider Habrocestum graecum Dalmas, 1920, until now only known from Greece, is for the first time recorded in Italy. Observations on ecology and behavior are also reported and pictures of its habitus and genitalia are provided. Furthermore, the first DNA barcode sequence for H. graecum is produced and made publicly available. The species has been observed in Puglia, in South-Eastern Italy, and a trans-Ionian dispersal pattern is most likely the cause of its presence both in Greece and Southern Italy, as reported for other taxa with similar distribution in different animal groups

Paraxial Skyrmionic beams

Vector vortex beams possess a topological property that derives both from the spatially varying amplitude of the field and also from its varying polarization. This property arises as a consequence of the inherent Skyrmionic nature of such beams and is quantified by the associated Skyrmion number, which embodies a topological property of the beam. We illustrate this idea for some of the simplest vector beams and discuss the physical significance of the Skyrmion number in this context.Comment: 6 pages, 6 figure

A drug safety evaluation of abiraterone acetate in the treatment of prostate cancer

Introduction: To evaluate the safety profile characteristics of abiraterone acetate (AA) in the treatment of metastatic prostate cancer (mPCa). Areas covered: In this literature review the authors evaluate safety data from phase III trials investigating the combination of abiraterone acetate plus prednisone (AAP) in patients with metastatic prostate cancer. In particular, the aim was to clarify its toxicity profile, long-term exposure impact, and the correlation with general health-related quality of life (HRQoL). Expert opinion: Based on the studies reviewed, it appears that abiraterone acetate has favourable outcomes, is effective and well tolerated, mostly in asymptomatic or slightly symptomatic patients, and has recognised toxicity profile characteristics. Incidence of adverse events (AEs), such as mineralocorticoid- and corticosteroid-releated AEs, and hepatotoxicity is well known and widely described. Understanding the toxicity profile of AA could assist decision-making in clinical practice

Human genetics of leishmania infections.

Identifying genetic risk factors for parasitic infections such as the leishmaniases could provide important leads for improved therapies and vaccines. Until recently most genetic studies of human leishmaniasis were underpowered and/or not replicated. Here, we focus on recent genome-wide association studies of visceral leishmaniasis (VL) and cutaneous leishmaniasis (CL). For VL, analysis across 2287 cases and 2692 controls from three cohorts identified a single major peak of genome-wide significance (Pcombined = 2.76 × 10-17) at HLA-DRB1-HLA-DQA1. HLA-DRB1*1501 and DRB1*1404/DRB1*1301 were the most significant protective versus risk alleles, respectively, with specific residues at amino acid positions 11 and 13 unique to protective alleles. Epitope-binding studies showed higher frequency of basic AAs in DRB1*1404-/*1301-specific epitopes compared to hydrophobic and polar AAs in DRB1*1501-specific epitopes at anchor residues P4 and P6 which interact with residues at DRB1 positions 11 and 13. For CL, genome-wide significance was not achieved in combined analysis of 2066 cases and 2046 controls across 2 cohorts. Rather, multiple top hits at P < 5 × 10-5 were observed, amongst which IFNG-AS1 was of specific interest as a non-coding anti-sense RNA known to influence responses to pathogens by increasing IFN-γ secretion. Association at LAMP3 encoding dendritic cell lysosomal associated membrane protein 3 was also interesting. LAMP3 increases markedly upon activation of dendritic cells, localizing to the MHC Class II compartment immediately prior to translocation of Class II to the cell surface. Together these GWAS results provide firm confirmation for the importance of antigen presentation and the regulation of IFNγ in determining the outcome of Leishmania infections