Profile Design of the Grooved Die and Rolling Force Prediction in the Cold Pilger Rolling Process

The objective of this study was to design the die groove profile and predict the rolling force produced when employing the variable curvature rolls and mandrel for manufacturing seamless pipes using the cold pilger rolling process. The parameters of the key process design were the diameter of the initial tube and final product, as well as the feed amount, reduction area, principal deformation zone, and roller radius. The rolling forces during the pilger rolling process were theoretically calculated to enable their prediction, and the characteristics of the cold pilger rolling process were identified. The calculated values were in close agreement with the experimental data. The die groove design is important in the prediction process because the dimensional accuracy of the tubes and the life of the dies are highly dependent on this design. The presented design method can be successfully applied to fulfill this objective. The tube shape and adequate tolerance can be attained by using the proposed design method. The mechanical properties of the pipe are evaluated by calculating the Q factor.

Method to obtain PRP and L-PRP for the use in routine medical practice of orthopedic traumatologist

The paper presents the results of experimental study of two methods for blood processing to obtain platelet-rich plasma (PRP). Due to the widespread clinical use of platelet-rich plasma in orthopedics and traumatology, a differential approach to the use of PRP and leukocyte- and platelet-rich plasma (L-PRP) has become relevant. Most commercial kits for PRP preparation significantly increase the cost of treatment. In addition, the main attention is focused on the concentration of platelets in the final product and the marketing features of a particular kit (separating gel, tube shape, anticoagulant, activator, etc.). The role of leukocytes in the features of the regenerative effect of platelet-rich plasma stays out of focus. The blood of volunteers was processed in two different ways and the cellular composition of the obtained products was analyzed. Sample No. 1 was used as a control for the baseline blood cell composition. Sample No. 2 was centrifuged in a sterile plastic tube, platelet rich plasma was collected manually. Sample No. 3 was centrifuged in a sterile modified syringe, platelet rich plasma was collected using a closed technique by means of connectors together with a rich layer. The results of statistical analysis showed that there were obtained totally different biological products with different concentrations of platelets and leukocytes. The first sample (control) had platelet concentration of (228.69 ± 39.15) × 109/l and leukocyte concentration of (5.18 ± 1.32) × 109/l. In the second sample (tube + manual sampling), platelet concentration was (429.38 ± 79.92) × 109/l and leukocyte concentration — (0.85 ± 0.34) × 109/l. The third sample (syringe plunger + closed vacuum collection) had platelet concentration of (541.15 ± 85.49) × 109/l and leukocytes of (6.56 ± 1.92) × 109/l. The data are given without regard to –12.5% deviation on dilution with citrate dextrose. As the result of the work, orthopedic traumatologists can use the simplest non-commercial methods for obtaining PRP and L-PRP in their practice depending on nosology and clinical tasks.

Reduced soil fauna decomposition in a high background radiation area

Decomposition of litter and organic matter is a very important soil ecosystem function where soil fauna play an important role. Knowledge of the responses in decomposition and soil fauna to different stressors is therefore crucial. However, the extent to which radioactivity may affect soil fauna is not so well known. There are some results showing effects on soil fauna at uranium mines and near Chernobyl from relatively high levels of anthropogenic radionuclides. We hypothesize that naturally occurring radionuclides affect soil fauna and thus litter decomposition, which will covary with radionuclide levels when accounting for important soil parameters. We have therefore used standardised litterbags with two different mesh sizes filled with birch leaves (Betula pubescens) to assess litter decomposition in an area with enhanced levels of naturally occurring radionuclides in the thorium (232Th) and uranium (238U) decay chains while controlling for variation in important soil parameters like pH, organic matter content, moisture and large grain size. We show that decomposition rate is higher in litterbags with large mesh size compared to litterbags with a fine mesh size that excludes soil fauna. We also find that litter dried at room temperature is decomposed at a faster rate than litter dried in oven (60⁰C). This was surprising given the associated denaturation of proteins and anticipated increased nutritional level but may be explained by the increased stiffness of oven-dried litter. This result is important since different studies often use either oven-dried or room temperature-dried litter. Taking the above into account, we explore statistical models to show large and expected effects of soil parameters but also significant effects on litter decomposition of the naturally occurring radionuclide levels. We use the ERICA tool to estimate total dose rate per coarse litterbag for four different model organisms, and in subsequent different statistical models we identify that the model including the dose rates of a small tube-shape is the best statistical model. In another statistical model including soil parameters and radionuclide distributions, 226Ra (or uranium precursory radionuclides) explain variation in litter decomposition while 228Ra (and precursors) do not. This may hint to chemical toxicity effects of uranium. However, when combining this model with the best model, the resulting simplified model is equal to the tube-shape dose-rate model. There is thus a need for more research on how naturally occurring radionuclides affect soil fauna, but the study at hand show the importance of an ecosystem approach and the ecosystem parameter soil decomposition.

Fabrication and Characterization of CdO Gas Sensor with Tube Shape

The based semiconductor-metal oxide gas 3D-detector of cadmium oxide has been fabricated from cadmium chloride salt upon a glass substrate via the technique of spray pyrolysis with a thickness around (0.5 ± 0.01 μm) utilizing precursors in form of water soluble at a flat glass substrate and a tube hollow design. Three different dimensions were used at temperature 450oC±5, in 0.1 and 0.2 M concentration, and their gas sensing characteristics toward the (CO) and (NO) gases at various concentrations (50, 100, and 500 ppmv) in the air were studied at the room temperature which are related to oil industry. Different inspection distances (0, 1 and 5 m) were carried out. Furthermore, structural and morphology properties were inspected via X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The results manifested that the composition of the formative oxide CdO is related to the tested oxidation gases sensitivity. And, the installation of hollow design is best from flat to capture the gas molecules.

Crashworthiness Analysis of a Thin-Walled Structure in the Frontal Part of Automotive Chassis

With increasing road accidents, researchers found a need to reduce the impact which gets transferred to the driver and passengers during a collision. Chassis is the main rigid component which transmits the impact or jerk to the entire vehicle. So, the changes can be done in the frontal head tube shape in order to achieve maximum energy absorption. The objective of this article is to produce a thin-walled impact absorption structure. The unique strength absorption, the maximum crushing force, all through the frontal impact are the primary dimensional parameters of the performance. Explicit dynamics feature of Ansys can be used and the results of Peak Force (PF) and Specific Energy Absorption (SEA) can be acquired virtually. Based on the results, the shape with the highest amount of SEA can be concluded as the best shape so that it can be used to absorb the maximum energy while collision of the vehicle takes place. The results show an increment of 30% in SEA.

Cuscuta sect. Californicae (Convolvulaceae) Revisited: ‘Cryptic’ Speciation and Host Range Differentiation

Abstract—Cuscuta californica complex (sensu lato, s. l.) is a western North American group of species in which the infrastaminal scales are reduced, making the morphological delimitation of species particularly challenging. A revision of this group was prompted by the discovery of an apparent new species from central California based primarily on molecular means. Driven by this finding, the morphological limits of C. californica s. l. species were comprehensively re-evaluated through a morphometric study. DNA sequences from plastid (trnL‐F region and rbcL), nuclear ribosomal ITS and 26S rDNA, as well as a low-copy nuclear pentatricopeptide repeat (PPR) gene were used to reconstruct evolutionary relationships among taxa. Last but not least, the host range of relevant taxa was determined using herbarium specimens. Molecular results strongly supported the new species, C. difficilis, which was found to be morphologically separated from C. brachycalyx only by subtle calyx lobe and corolla tube shape differences. Despite sharing some of the hosts, all the members of C. californica s. l. exhibited a differentiation of their host ranges. An identification key and description of the new species were provided together with a discussion on the systematics and host range of C. californica s. l.. Hybridization, accompanied by plastid capture, was suggested as a possible mechanism of speciation for C. brachycalyx.