Reinforced Concrete Circular T-Shaped Deep Beams – Finite Element Investigation

The current work investigates the behavior and strength of T-shaped cross section ring deep beams through a Finite element parametric study. Currently, ring diameter, loading type, concrete compressive strength and number of supports are taken into consideration. It is found that increasing ring diameter of beam by 12.5-25% leads to increase the maximum positive moment, maximum negative moment, maximum torsional moment and midspan deflection by 1.1-2.2%, 2.2-4.3%, 3-6% and 16-33%, respectively, while the load ultimate capacity increases by 11-17%. The positive and torsional moments at midspan and midspan deflection decrease by 23-36%, 3-11% and 6-14%, respectively when the loading type varies from concentered to full uniformly load over a span length of 33, 50, 67 and 100%, respectively. In a related context, this change in load type leads the negative moment at support and the load ultimate capacity to increase by 2-21% and 6-85%, respectively. The midspan positive moment, negative moment, torsional moment and load ultimate capacity increase by 20.4-71.3%, 20-69.7%, 15.6-43.8% and 21-73%, respectively, whereas deflection decreases by 1.4-11%, when increasing the compressive concrete strength by 45-190%. Finally, it is found that the load ultimate capacity increases by 82-348%, when number of supports increases by 25-100%, while torsional moment, maximum positive moments, maximum negative moments and midspan deflection decrease by 11-50%, 38-76.4%, 38.6-76.8% and 14-39%, respectively due to this increase in the number of supports.

Cementation of Cd Ions on Zinc Using a Rotating Fixed Bed Impeller Basket Reactor

Cementation or metal displacement reaction is one of the most effective techniques for removing toxic metals from industrial waste solutions. Aims: The main purpose of this work is to study the rate of cementation of cadmium by using a rotating bed of Zn Raschig rings packed in a perforated impeller basket for the investigation of the removal of Cd 2+ from waste solution. Study Design: The reactor was tested for Cd2+ concentration removed, the diameter of Zinc Raschig rings, and the rotational speed of the basket. Methodology: The results indicate that there are two rates of cementation for Cd-Zn system, a high rate at the beginning, followed by a lower rate after the initial period. The results also show that percentage removal of Cd2+ ions from solution increases by increasing the speed of basket rotation, and as the diameter of Zn Raschig ring packed in the basket reactor, increases the removal of Cd2+ decreases. The cadmium deposits on zinc as powder. Results: The removal of Cd2+ is optimum for ring diameter of 0.5 cm, initial concentration of 100 ppm, and basket rotation speed of 500 rpm. The experimental data fit the following equation: Sh=0.041 Sc0.33Re0.40. This equation can be used for the design scale-up and operation of reactors used to remove Cd2+ from wastewater by cementation. Conclusion: Rates of cementation were expressed in terms of the rate of mass transfer, the mass transfer coefficient increases as the rotational speed of the basket increases.

Research of design solutions of water cooling systems for tanks

Установки водяного охлаждения резервуаров являются частью системы автоматического пожаротушения резервуарного парка и представляют собой комплекс устройств, оборудования и трубопроводов. Непосредственное охлаждение стенки резервуара осуществляется через верхнее горизонтальное кольцо орошения, выполненное в виде перфорированного трубопровода или трубопровода с оросителями. При этом до настоящего времени не была определена зависимость фактически защищаемой площади стенки от расходов воды, подаваемой через отверстия и/или оросители при их различном положении по отношению к стенке и верхней кромке резервуара. Цель исследования - экспериментальное определение оптимальных конструктивных и технологических решений элементов установок водяного охлаждения резервуара. Для изучения процессов теплового нагрева и охлаждения боковой поверхности резервуара проведены гидравлические и огневые испытания моделей секции установки водяного охлаждения - горизонтального кольца орошения. По результатам испытаний определена эффективность различных конструкций в зависимости от изменяемых технологических параметров (давления и расхода воды в кольце орошения), диаметра отверстий перфорированного трубопровода и шага между ними, угла расположения устройств подачи воды относительно горизонтальной поверхности сечения резервуара, расстояния от кольца орошения до стенки резервуара и его верхней кромки. Water cooling units for tanks are a part of automatic fire extinguishing system of the tank farm and represent a complex of units, equipment and pipelines. Tank wall is cooled down directly through upper horizontal spray distribution ring, made in the form of a perforated pipeline or a pipeline with sprinklers. With this, correlation between actually protected area of the wall and flow rate of water supplied through the holes and/or sprinklers at their different positions in relation to the wall and the upper edge of the tank, has not been determined so far. The purpose of the study is to experimentally determine the optimal design and technological solutions of the elements of tank water cooling units. To study the processes of thermal heating and cooling of the side surface of the tank, hydraulic and fire tests of models of the section of the water cooling unit (the horizontal spray distribution ring) were carried out. According to the test results, the efficiency of various structures was determined depending on the technological parameters being changed (pressure and water flow in the spray distribution ring), diameter of the holes of the perforated pipeline and pitch between them, angle of the water supply units relative to the horizontal surface of the tank section, distance from the spray distribution ring to the tank wall and its upper edge.

Pre-Orientale Southwest Peak-Ring Basin: Gravity Structure, Geologic Characteristics, and Influence on Orientale Basin Ring Formation and Ejecta Emplacement

The Orientale impact basin is the youngest and most well-preserved of the lunar multi-ring basins. The generally well-preserved ring structures and basin facies are distinctly anomalous in the southwestern quadrant; the outer Cordillera ring extends significantly outward, the Outer and Inner Rook mountain rings are more poorly developed and show anomalous characteristics, and the Montes Rook Formation varies widely from its characteristics elsewhere in the basin interior. Based on the gravity, image, and topography data, we confirmed that the southwest region of the Orientale basin represents the location of a pre-existing ~320 km rim–crest diameter peak–ring basin centered at 108.8°W, 28.4°S, and characterized by an ~170 km peak–ring diameter. We model the structure and morphology of this large pre-Orientale peak–ring basin (about one-third the diameter of Orientale) and show that its presence and negative relief had a distinctive influence on the development of the basin rings (disrupting the otherwise generally circular continuity and causing radial excursions in their locations) and the emplacement of ejecta (causing filling of the low region represented by the peak–ring basin, creating anomalous surface textures, and resulting in late stage ejecta movement in response to the pre-existing peak–ring basin topography. The location and preservation of the peak–ring basin Bouguer anomaly strongly suggest that the rim crest of the Orientale basin excavation cavity lies at or within the Outer Rook Mountain ring.

The Ring Rotation Illusion: Properties and Links of a Novel Illusion of Motion

We report a novel visual illusion we call the Ring Rotation Illusion (RRI). When a ring of stationary points replaces a circular outline, the ring of points appears to rotate to a halt, although no actual motion has been displayed. Three experiments evaluate the clarity of the illusory rotation. Clarity decreased as the diameter of the circle and ring increased and increased as the number of points forming the ring increased. The optimal interstimulus interval (ISI) between the circle and ring was 90 ms when stimulus presentations lasted 100 ms but 0 ms with 500 ms presentations. We compare the RRI to the Motion Bridging Effect (MBE), a similar illusion in which a stationary ring of points replaces an initial ring of points that spins so rapidly it looks like a stationary outline. A rotation of the stationary ring is seen that usually matches the direction of the initial ring’s invisible spin. Participants reported a slightly more frequent and clearer motion percept with the MBE than RRI. ISI manipulations had similar effects on the two illusions, but the effects of number of points and ring diameter were largely restricted to the RRI. We suggest that both the RRI and MBE motion percepts are produced by a visual heuristic that holds that the transition from an outline circle to a ring of points is plausibly explained by a rapid spin decelerating to a halt, but in the case of the MBE, an additional direction-sensitive mechanism contributes to this percept.

Evaluation of bacteriocin-producing lactic acid bacteria strains isolated from “nem chua Thu Duc”

This study aimed to select some lactic acid bacteria (LAB) strains to produce bacteriocin isolated from two different local brand names of nem chua Thu Duc, a Vietnamese traditional fermented meat product. Eight different LAB strains were isolated from products. However, only Pediococcus pentosaceus isolated from 72-h fermented “Ba Chin” products and Weissella paramesenteroides isolated from 120-h fermented “Diem” products were selectively screened for their bacteriocin production. The antimicrobial activity was detected by the agar diffusion method against Escherichia coli ATCC 25922, Salmonella enterica serovar Typhimurium ATCC 13076, Staphylococcus aureus ATCC 6538, and Bacillus cereus ATCC 25924 used as target strains. Bacteriocin of Pediococcus pentosaceus strain showed a high antibacterial ability with a sterile ring diameter that produces an average of 12.20 - 16.07 mm. Bacteriocin of Weissella paramesenteroides strain only showed inhibitory activity on the growth of indicator microorganisms with an average inhibitory ring diameter of 9.75 - 15.27 mm. In conclusion, it seems like both bacteriocin-producing P. pentosaceus and W. paramesenteroides give potential applications as a starter culture, bio-preservation and bio-safety control in fermented meat as well as other kinds of fermented foods.

How does Sec63 affect the conformation of Sec61 in yeast?

The Sec complex catalyzes the translocation of proteins of the secretory pathway into the endoplasmic reticulum and the integration of membrane proteins into the endoplasmic reticulum membrane. Some substrate peptides require the presence and involvement of accessory proteins such as Sec63. Recently, a structure of the Sec complex from Saccharomyces cerevisiae, consisting of the Sec61 channel and the Sec62, Sec63, Sec71 and Sec72 proteins was determined by cryo-electron microscopy (cryo-EM). Here, we show by co-precipitation that the accessory membrane protein Sec62 is not required for formation of stable Sec63-Sec61 contacts. Molecular dynamics simulations started from the cryo-EM conformation of Sec61 bound to Sec63 and of unbound Sec61 revealed how Sec63 affects the conformation of Sec61 lateral gate, plug, pore region and pore ring diameter via three intermolecular contact regions. Molecular docking of SRP-dependent vs. SRP-independent peptide chains into the Sec61 channel showed that the pore regions affected by presence/absence of Sec63 play a crucial role in positioning the signal anchors of SRP-dependent substrates nearby the lateral gate.

The Role of Back Optic Zone Diameter in Myopia Control with Orthokeratology Lenses

We compared the efficacy of controlling the annual increase in axial length (AL) in myopic Caucasian children based on two parameters: the back optic zone diameter (BOZD) of the orthokeratology (OK) lens and plus power ring diameter (PPRD) or mid-peripheral annular ring of corneal steepening. Data from 71 myopic patients (mean age, 13.34 ± 1.38 years; range, 10–15 years; 64% male) corrected with different BOZD OK lenses (DRL, Precilens) were collected retrospectively from a Spanish optometric clinic. The sample was divided into groups with BOZDs above or below 5.00 mm and the induced PPRD above or below 4.5 mm, and the relation to AL and refractive progression at 12 months was analyzed. Three subgroups were analyzed, i.e., plus power ring (PPR) inside, outside, or matching the pupil. The mean baseline myopia was −3.11 ± 1.46 D and the AL 24.65 ± 0.88 mm. Significant (p < 0.001) differences were found after 12 months of treatment in the refractive error and AL for the BOZD and PPRD. AL changes in subjects with smaller BOZDs decreased significantly regarding larger diameters (0.09 ± 0.12 and 0.15 ± 0.11 mm, respectively); in subjects with a horizontal sector of PPRD falling inside the pupil, the AL increased less (p = 0.035) than matching or outside the pupil groups by 0.04 ± 0.10 mm, 0.10 ± 0.11 mm, and 0.17 ± 0.12 mm, respectively. This means a 76% lesser AL growth or 0.13 mm/year in absolute reduction. OK corneal parameters can be modified by changing the OK lens designs, which affects myopia progression and AL elongation. Smaller BOZD induces a reduced PPRDs that slows AL elongation better than standard OK lenses. Further investigations should elucidate the effect of pupillary diameter, PPRD, and power change on myopia control.

Поверхностно-излучающий квантово-каскадный лазер с кольцевым резонатором

The results of studies of quantum-cascade laser with a surface emission through a grating formed in the layers of the top cladding of the waveguide by ion beam milling are presented. The active region of the QCL heterostructure was formed based on a heteropair of In0.53Ga0.47As / Al0.48In0.52As solid alloys with two-phonon resonance design. It is shown that lasing at room temperature close to 7.9 µm is demonstrated for a laser with a ring diameter of 191 µm. The mode spacing corresponds to whispering gallery modes.

Control of septum thickness by the curvature of SepF polymers

Gram-positive bacteria divide by forming a thick cross wall. How the thickness of this septal wall is controlled is unknown. In this type of bacteria, the key cell division protein FtsZ is anchored to the cell membrane by two proteins, FtsA and/or SepF. We have isolated SepF homologs from different bacterial species and found that they all polymerize into large protein rings with diameters varying from 19 to 44 nm. Interestingly, these values correlated well with the thickness of their septa. To test whether ring diameter determines septal thickness, we tried to construct different SepF chimeras with the purpose to manipulate the diameter of the SepF protein ring. This was indeed possible and confirmed that the conserved core domain of SepF regulates ring diameter. Importantly, when SepF chimeras with different diameters were expressed in the bacterial hostBacillus subtilis, the thickness of its septa changed accordingly. These results strongly support a model in which septal thickness is controlled by curved molecular clamps formed by SepF polymers attached to the leading edge of nascent septa. This also implies that the intrinsic shape of a protein polymer can function as a mold to shape the cell wall.