An exceedingly rare localization of a brown tumor in a hemodialysis patient

Brown tumor, which is seen in the context of hyperparathyroidism, is defined as a uremic bone disease characterized by increased osteoclastic activity and fibroblastic proliferation in the involved bone. In chronic renal failure, there is an excessive parathyroid hormone secretion due to hypocalcemia, hyperphosphatemia, and vitamin D deficiency. Brown tumor of the femur, facial bones, mandible, sternum, ribs, and pelvis are rare, whereas, it rarely involves sacrum. Here, we presented a brown tumor of the sacrum that developed secondary to parathyroid hyperplasia in a patient receiving hemodialysis.     

Elastic limits of a radially heated thick-walled cylindrically curved panel

In analogy to the theory of wide curved beams, the basic equations for a cylindrically curved panel of homogeneous thickness in a state of plane strain subject to a radial temperature gradient are derived. The ends of this thick-walled shell are presupposed to be guided in such a way that a displacement in circumferential direction may occur and that the radius of the initial middle surface remains unchanged. Then, couples act on those ends, giving rise to pure bending conditions. Based thereon, the stresses occurring for a heated inner and/or outer surface are analyzed, and—taking thermal softening and hence a reduced yield stress into account—the elastic limits according to the yield criteria of Tresca and von Mises are discussed comprehensively.     

Evaluation of a physical length scale for granular materials

Classical continuum mechanics considers the interaction of microstructural units of the material through stresses and displacements of material points. Therefore, conventional continuum mechanics approaches can not incorporate any intrinsic material length scale. However in reality interaction of grains may include rotations and the corresponding couple stresses as well, and real materials have a number of important length scales (e.g., grains, particles, fibers, etc.). An equation for determining the length scale is proposed. The proposed length scale equations include the effect of plastic deformation (microrotation), the effect of normal stress and contact area. The proposed length scale is implemented into elastic–elastoplastic Cosserat formulation. The effect of length scale on the finite element simulation and yield surface was evaluated by using the proposed length scale equation. The importance of length scale on the constitutive modeling of granular materials is analyzed in numerical simulations.     

Removal of fluoride from water by using granular red mud: Batch and column studies

This paper describes the removal of fluoride from water using granular red mud (GRM) according to batch and column adsorption techniques. For the batch technique, the experiments demonstrated that maximum fluoride removal was obtained at a pH of 4.7 and it took 6h to attain equilibrium and equilibrium time did not depend upon the initial fluoride concentration. Kinetics data were fitted with pseudo-second-order model. The Redlich-Peterson and Freundlich isotherm models better represented the adsorption data in comparison to the Langmuir model. Column experiments were carried out under a constant influent concentration and bed depth, and different flow rates. The capacities of the breakthrough and exhaustion points decreased with increase of the flow rate. Thomas model was applied to the experimental results. The modelled breakthrough curves were obtained, and they were in agreement with the corresponding experimental data. The column adsorption was reversal and the regeneration operation was accomplished by pumping 0.2M of NaOH through the loaded GRM-column.     

SWOT analysis for safer carriage of bulk liquid chemicals in tankers

The application of strengths, weaknesses, opportunities and threats (SWOT) analysis to formulation of strategy concerned with the safe carriage of bulk liquid chemicals in maritime tankers was examined in this study. A qualitative investigation using SWOT analysis has been implemented successfully for ships that are designed to carry liquid chemicals in bulk. The originality of this study lies in the use of SWOT analysis as a management tool to formulate strategic action plans for ship management companies, ship masters and officers for the carriage of dangerous goods in bulk. With this transportation-based SWOT analysis, efforts were made to explore the ways and means of converting possible threats into opportunities, and changing weaknesses into strengths; and strategic plans of action were developed for safer tanker operation.     

Indium rich InGaN solar cells grown by MOCVD

This study focuses on both epitaxial growths of In_xGa_1?xN epilayers with graded In content, and the performance of solar cells structures grown on sapphire substrate by using metal organic chemical vapor deposition. The high resolution X-ray and Hall Effect characterization were carried out after epitaxial InGaN solar cell structures growth. The In content of the graded InGaN layer was calculated from the X-ray reciprocal space mapping measurements. Indium contents of the graded InGaN epilayers change from 8.8 to 7.1 % in Sample A, 15.7–7.1 % in Sample B, and 26.6–15.1 % in Sample C. The current voltage measurements of the solar cell devices were carried out after a standard micro fabrication procedure. Sample B exhibits better performance with a short-circuit current density of 6 mA/cm², open-circuit voltage of 0.25 V, fill factor of 39.13 %, and the best efficiency measured under a standard solar simulator with one-sun air mass 1.5 global light sources (100 mW/cm²) at room temperature for finished devices was 0.66 %.     

Synthesis and Characterization of Nb Substitution on (Bi-Pb)-2223 Superconductors

In this study, samples of \(\hbox {Bi}_{1.65}\hbox {Pb}_{{ 0.35-x}}\hbox {Nb}_{{ x}}\hbox {Sr}_{2}\hbox {Ca}_{2}\hbox {Cu}_{3}\hbox {O}_{10+\delta }\) were prepared by solid-state reaction method and the effect of Nb substitution for Pb on the structural and superconducting properties of this material was investigated. The room-temperature X-ray diffraction patterns indicated that all the samples have the dominant phase of high-\({T}_{\mathrm{c}}\) (Bi-2223). However, other phases such as Bi-2212 and some impurity phases like \(\hbox {SrCu}_{2}\hbox {O}_{2}\), \(\hbox {CuNb}_{2}\hbox {O}_{6}\), \(\hbox {CaCuO}_{3}\) and CuO were also obtained from XRD patterns. An increasing amount of \(\hbox {Nb}^{+5}\) substitutions for \(\hbox {Pb}^{+2}\) led to a phase transition from Bi-2223 to Bi-2212. Electrical resistivity and magnetic measurements revealed that the critical temperature and the critical current density decreases with increasing Nb content due to the enhancement of Bi-2212 phase and appearance of impurities. SEM images indicated that samples porosity changes due to the disrupted grain growth with the substitution of Pb ions with Nb ions.     

A reinforcement learning approach for transaction scheduling in a shuttle-based storage and retrieval system

With recent Industry 4.0 developments, companies tend to automate their industries. Warehousing companies also take part in this trend. A shuttle-based storage and retrieval system (SBS/RS) is an automated storage and retrieval system technology experiencing recent drastic market growth. This technology is mostly utilized in large distribution centers processing mini-loads. With the recent increase in e-commerce practices, fast delivery requirements with low volume orders have increased. SBS/RS provides ultrahigh-speed load handling due to having an excess amount of shuttles in the system. However, not only the physical design of an automated warehousing technology but also the design of operational system policies would help with fast handling targets. In this work, in an effort to increase the performance of an SBS/RS, we apply a machine learning (ML) (i.e., Q-learning) approach on a newly proposed tier-to-tier SBS/RS design, redesigned from a traditional tier-captive SBS/RS. The novelty of this paper is twofold: First, we propose a novel SBS/RS design where shuttles can travel between tiers in the system; second, due to the complexity of operation of shuttles in that newly proposed design, we implement an ML-based algorithm for transaction selection in that system. The ML-based solution is compared with traditional scheduling approaches: first-in-first-out and shortest process time (i.e., travel) scheduling rules. The results indicate that in most cases, the Q-learning approach performs better than the two static scheduling approaches.