Inka Hydraulic Engineering at the Tipon Royal Compound (Peru)

The Inka site of Tipon had many unique hydraulic engineering features that have modern hydraulic theory counterparts. For example, the Tipon channel system providing water to the Principal Fountain had a channel contraction inducing critical flow as determined by CFD analysis- this feature designed to induce flow stability and preserve the aesthetic display of the downstream Waterfall. The Main Aqueduct channel sourced by the Pukara River had a given flow rate to limit channel overbank spillage induced by a hydraulic jump at the steep-mild slope transition channel location as determined by use of modern CFD methods- this flow rate corresponds to the duplication of the actual flow rate used in the modern restoration using flow blockage plates placed in the channel to limit over-bank spillage. Additional hydraulic features governing the water supply to agricultural terraces for specialty crops constitute further sophisticated water management control systems discussed in detail in the text.

Размещение водорода в оксигидриде титана

Possible models of the arrangement of hydrogen atoms at the sites of the cubic lattice of titanium oxyhydride TiOyHp with vacancies in the metallic and nonmetallic sublattices are considered. It was found that titanium oxyhydride retains the B1 type crystal lattice of the initial cubic titanium monoxide TiOy and contains structural vacancies in the metal and oxygen sublattices. Comparison of the found analytical expressions for the intensity of diffraction reflections with experimental X-ray and neutron diffraction data showed that interstitial H atoms in oxyhydrides occupy vacant octahedral positions 4(b) of the oxygen sublattice. No displacement of H atoms in tetrahedral positions 8(c) is observed. A disorder-order phase transition channel associated with the formation of an ordered monoclinic titanium oxyhydride of the Ti5O5 type was found. The distribution functions of Ti, O, and H atoms in the partially ordered monoclinic oxyhydride Ti5.33O5.12H0.74 (Ti0.89O0.85H0.12) with a Ti5O5-type structure are calculated for the first time, and the concentrations of these atoms at the positions of its lattice were found.

Optimizing reaction coordinate by flux maximization in the transition path ensemble

Transition path ensemble is a collection of reactive trajectories, all of which largely keep going forward along the transition channel from the reactant state to the product one, and is believed to possess the information necessary for the identification of reaction coordinate. Previously, the full coordinates (both position and momentum) of the snapshots in the transition path ensemble were utilized to obtain the reaction coordinate (J. Chem. Phys. 2016, 144, 114103; J. Chem. Phys. 2018, 148, 084105). Here, with the conformational (or position) coordinates alone, it is demonstrated that the reaction coordinate can be optimized by maximizing the flux of a given coordinate in the transition path ensemble. In the application to alanine dipeptide in vacuum, dihderal angles ϕ and θ were identified to be the two best reaction coordinates, which was consistent with the results in existing studies. A linear combination of these two coordinates gave a better reaction coordinate, which is highly correlated with committor. Most importantly, the method obtained a linear combination of pairwise distances between heavy atoms, which was highly correlated with committor as well. The standard deviation of committor at the transition region defined by the optimized reaction coordinate is as small as 0.08. In addition, the effects of practical factors, such as the choice of transition path sub-ensembles and saving interval between frames in transition paths, on reaction coordinate optimization were also considered.

Analisis Kavitasi pada Saluran Transisi dan Peluncur Pelimpah Bendungan Kluet – Model Fisik Skala 1:60

River Region of Baru-Kluet has a steep slope contour and high rainfall so that it is vulnerable to flooding while during the dry season rice fields experience drought due to lack of water. Therefore, a dam is built to mitigate these issues. The spillway is a flow-control component in the dam which is used to improve regulation and enlarge the flow rate that will cross the spillway building. Spillway that has a steep slope is vulnerable to hydraulic behavior called cavitation. The experiment was carried out at the River and Coast Laboratory of Syiah Kuala University, Indonesia. This study aims to determine the value of the damage cavitation index interval in each series and discharge variation. Cavitation index analysis method used formula of ratio between local water pressure and flow velocity. Flow velocity and pressure at each outflow discharge was collected from the experiment. The results of the damage cavitation index interval in the 0 series and the modified series are located at level 1 for the transition region, level 3 for the launcher region and level 2 for the launcher region of modified series. It is found that the change in series 0 to a modified series with extending width in the side channel, lowering the elevation of side channel, and displacement sill in the transition channel with the aim of reducing the flow velocity. This change still has the possibility of cavitation damage, but it is much safer than the cavitation results of the 0 series. High quality of materials or concrete are not recommended because they are expensive and economically unfeasible, therefore the use of slot aeration/aerator is a suitable option for this case. Keyword: Dam, spillway, cavitation, model test.

Analysis of the Variable Cross-Section Duct and Straightening Device Geometry Effects on the Hydrogen Combustion Process

The development and research of high-speed aircrafts and their individual parts is an urgent scientific task. In the scientific literature there is information about the integral characteristics of aircrafts of this type, but there is no detailed consideration of such an important part as the transition channel between the air intake and the combustion chamber. The article considers several flow path configurations. The numerical simulation results of hydrogen combustion in the channels of variable cross section using a detailed kinetic mechanism are presented. Based on the analysis of the data obtained, the models of the transition channel and the combustion chamber showing the best characteristics were selected. The impulse and the fuel combustion efficiency are used as criteria for comparing the flow paths. The difference in the application of two calculation methods is described. The presented results and calculation methods can be used at the stage of computational research of the working processes in advanced power plants.

Path sampling simulations reveal how the Q61L mutation restricts the dynamics of KRas

The GTPase KRas is a signaling protein in networks for cell differentiation, growth, and division. KRas mutations can prolong activation of these networks, resulting in tumor formation. When active, KRas tightly binds GTP. Several oncogenic mutations affect the conversion between this rigid state and inactive, more flexible states. Detailed understanding of these transitions may provide valuable insights into how mutations affect KRas. Path sampling simulations, which focus on transitions, show KRas visiting several states, which are the same for wild type and the oncogenic mutant Q61L. Large differences occur when converting between these states, indicating the dramatic effect of the Q61L mutation on KRas dynamics. For Q61L a route to the flexible state is inaccessible, thus shifting the equilibrium to more rigid states. Our methodology presents a novel way to predict dynamical effects of KRas mutations, which may aid in identifying potential therapeutic targets.Author summaryCancer cells frequently contain mutations in the protein KRas. However, KRas is a challenging target for anti-cancer drugs, in part because the dynamic behavior of flexible regions in the protein is difficult to characterize experimentally, and occurs on timescales that are too long for straightforward molecular dynamics simulations. We have used path sampling, an advanced simulation technique that overcomes long timescales, to obtain atomistic insight into the dynamics of KRas. Comparing the oncogenic mutant Q61L to the wild type revealed that the mutation closes off one transition channel for deactivating KRas. Our approach opens up the way for predicting the dynamical effects of mutations in KRas, which may aid in identifying potential therapeutic targets.

The Design of Re-Issued Data Memory Circuit Based on Telemetry System

Radio telemetry is used as a major way on monitoring flight test of airplanes. As information transition channel is disturbed or interrupted significantly during the blackout area during flight, the carrier information will not be transmitted normally. However, the airplane data during the blackout period has to be monitored seriously. This issue can be resolved by building re-issued data memory function into a telemetry system. This paper looks at the research of re-issued data memory technology and proposes a new design of re-issued data memory circuit for realizing the negative trigger delay storage of data flow in telemetry system during blackout period. The delayed data in the storage will be transmitted again later. The new designed circuit uses multiple re-issued data memory methods to satisfy the requirements of different telemetry tests and measurements, assuring complete data during airplane flight test.