Implications of Convection within the Moon

The Chang’E-4 lander landed on January 3, 2019, achieving the first lunar soft landing and cruise exploration by humans on the far side of the Moon. Compared with landing missions on the near side of the Moon, the Chang’E-4 landing site is in the South Pole–Aitken Basin on the far side, where the terrain is more rugged. Direct communication with Earth from the far side of the Moon is impossible, and relay support is necessary. Therefore, the complex terrain and relative constraints of relay communication represent important considerations for the design of the Chang’E-4 flight control process. The flight results of the Chang’E-4 show that the flight procedure performed perfectly. High-precision orbit control, a soft landing, and lunar surface work with support from the stable relay communication link were all realized. Presently, the payload and Moon night temperature acquisition equipment are powered for acquiring continuous on-orbit science exportation data. The interaction effect between the engine plume and lunar surface during the approach process, and an evaluation of the landing cushion range are estimated in this paper through analysis of the telemetry data. The mining and analysis of the on-orbit data from the Chang’E-4 lander can be used to optimize the simulation and analysis models and lay a solid technical foundation for research on the Moon’s far-side environment.

There were many scholars having made discussion about Su Shi's Ode of Red Cliff. And this work has also been selected as a teaching material of Chinese Language subject of senior high school students. The main reasons behind them are that the piece of work is a literary work, and is also a historical record. Nevertheless, in the aspect of literature, it is read from the viewpoint of appreciation; and in the aspect of historical record, it is an exploration of the old facts. Overall speaking, the frame of mind of Su Shi still cannot be seen from the work.Speaking of the term ”frame of mind,” Su Shi's work of Ode of Red Cliff is a reflection of the soul of a person in poor situation, who let his mood extend far and outward. What is expressed are the reflection of hearts of the people in the world and the dilution of personal depression. Speaking of the reflection of hearts of the people in the world, it is a free galloping of soul. No need to pay efforts for fame, and no need to pay efforts for wealth, a person liberates his mind and lets himself be carefree as much as possible. This is just as what Zhuang Zhou called, ”sitting in forgetfulness” in the harmony of human and nature. And speaking of the dilution of personal depression, it is an extreme expansion of thinking. It refers that when general people encounter a mishap, they must feel difficult to free themselves from grief. But the people with highly expanded thinking can turn the grief in their hearts to be sublime of love, and change the original anxious and worrying mind to be refreshed and clear situation. For the sublime of affection and the situation of clarity, if a person is not broadminded or does not have great intelligence, the person cannot achieve them at all. And the person, Su Shi, could overcome his sorrow. From here, we can imagine his broadmindedness and thorough thinking.Besides, between the Heaven and the Earth, some things are changeable, and some things are unchanged. No matter things are changeable or unchanged, taking the moon for example, the moon is after all still the moon. The full moon or the crescent moon is merely the turning wheel of the moon. It is known that the main body of the moon is normal, and its being full or crescent is a phenomenon. The constantly changing phenomena of its main body will finally unite to become one. Therefore, it is not necessary to care about the main body or the phenomenon. If a person does not care about details of things, all the things existed are just a phenomenon, and phenomenon can never leave all the things existed. In this way, flowers bloom, water flows, and everything goes back to the nature. Then, what argument will there be? Just because Su Shi did not have any argument with anybody, he had ”realization.” Just because of his ”realization,” he had things to express. Just because he had things to express, no matter how difficult the situation was, it did not bother his heart at all. Therefore, the words ”do not know” in the line, ”Do not know that the East was already white” are the summary of the sublimed and penetrated realization of his frame of mind. Hence, reading the work in this way, we can fully understand the reasons of his writing the work, Ode of Red Cliff.

Decision about first day of qamariyah months, especially in regard to worship (Ramadan, Shawwal, Zulhijjah) is determined by the appearance of the new moon. When the sun sets and the moon is above the horizon, which is an indication that the new moon has been there. But in reality, Ulama differ in determining whether the initial first day of qomariah months shall be based rukyat (observe of moon appearance) or can be based hisab (calculation). This is not apart from understanding dalil (reason based on Prophet exemplary).

Abstrak Traditionally, the first day of each month is the day (beginning at sunset) of the first sighting of the hilal (crescent moon) shortly after sunset. Beside that, the astronomical new moon times and dates are already computed exactly for thousands of years backward and forward. Some nations have used the lunar phase cycle as the basis for their calendars. In a majority of Nadlatul Ulama (NU), oppose the use of calculations, on the grounds that the latter would not conform with Muhammad's recommendation to observe the new moon of Ramadan and Shawwal in order to determine the beginning of these months. This Indonesia’s largest Muslim organization, prefers to utilize the method called imkanur rukyat , which requires a clear, visible sighting of the moon. In the other side, Muhammadiyah organization sets the first Ramdhan based on mathematical and astronomical calculations known as hisab wujudul hilal . This article focuses to discuss further about how Muhammadiyah sets the first day of Hijrah calendar.

Crescent visibility importantly depends on some variables such as; Sun-Crescent elongation (ArcL, arc of light), Crescent relative altitude due to Sun (ArcV, arc of vision), moon age, and moon lag (briefly Lag only). Furthermore , relative position of Sun due to ecliptic can affects Crescent position and its visibility. There is two significa nt ly relative position of Sun i.e. Summer Solstice which happens on June 21-22, and Winter Solstice which occurs on December 21-22. In this paper, it will be discuss ed about what is minimum limit of Crescent visibility on those phenomena. Writer used data from 68 BMKG data (2008-2015), 295 Yallop data (1861-1992), and 36 Caldwell data (1987-2012), but they are used when Summer and Winter Solstice only. It can be concluded that the minimum limit of Crescent visibility are, ArcL = 10°30’00”, ArcV = 9°30’00”, moon age 20 hours 24 minutes, lag 58 minutes 48 seconds and Crescent width 0,24 arc minutes on June 26, 1987 at latitude 42°42’00” South and longitude 84°30’00” West, occured 4 days after Summer solstice.

Este trabajo analiza el mito de la Media luna en Pedro Páramo y las connotaciones que tiene en relación a lo masculino, lo femenino, la fertilidad y la muerte. Para descubrir cómo en esta novela quedaron grabados dos aspectos del ser mexicano.

Doppler tracking data from the Lunar Orbiter series of spacecraft have been used in a more complete analysis of the spherical harmonic coefficients of the lunar gravitational field through thirteenth degree and order. The value obtained for the mass of the Moon,GM = 4902.84 km3 s−2, is in good agreement with previous results and with results obtained by alternate procedures. Acceleration contour plots, derived from the gravitational coefficients, show correlations with surface features on the near side of the Moon, but are of questionable validity for the far side because of the lack of direct tracking data on the far side. Based on the most recent gravitational field data, the current estimate for the polar moment of inertia of the Moon isC/Ma 2 = 0.4019-0.002 +0.004. This value indicates that the interior of the Moon can be homogeneous, but some results presented strongly suggest that the Moon is differentiated, with an excess of mass in the direction toward the Earth.

Effects of different volumetric fractions and Reynolds number on forced convection heat transfer through water/aluminum oxide nanofluid in a horizontal tube are investigated. The flow regime is laminar and the method of simulation is the axisymmetric lattice Boltzmann method (ALBM). The profiles of velocity and temperature were uniform at the input section, on the tube walls the uniform heat flux was considered; moreover, hydrodynamic, and thermal development conditions at the output section were applied. It was observed that an increase in the volumetric concentration of the nanoparticles added to the forced convection heat transfer coefficient and Nusselt number of the nanofluid, as compared to the base fluid. For a volumetric fraction of 5% and Reynolds number of 100 at the input section of the tube (0.1≤X/D≤7) the forced convection heat transfer coefficient increased by 24.165%, while an average increase of 21.361% was observed along the entire length of the tube (0≤x/D≤30). A comparison between the improvements in heat transfer at the two input temperatures, it was found that the forced convection heat transfer coefficient and Nusselt number will increase further at the lower input temperature; Moreover, with increasing the Reynolds number, the percent improvements in forced convention heat transfer coefficient and Nusselt number increased.

A case of formation of convective clouds over the center-westernpart of Santa Catarina State during the morning-time was studied. Duringthe night-time of 06 Jun 2007, a large area of low top cloudiness (cumulusand stratocumulus) covering Parana and Santa Catarina States propagatedeastward; embedded in this cloud system, over the center-western part ofSanta Catarina State, the onset of convective clouds took place during themorning-time of 07 Jun 2007. Later on, the convective cloud systemenhanced, propagated eastward, interacted with other diurnal convectiveclouds, weakened during night-time and dissipated up shortly before themorning-time of 08 Jun 2007. Simulations using the MM5 regional modelwith horizontal grid spacing of 12 km showed that Serra do Mar acted asbarrier to the low level northwesterly flow from Mato Grosso do Sul,bringing about atmospheric convergence at the western side of Serra doMar; associated with this convergence, the presence of low level jets (LLJ)or a maximum velocity core (MVC), like those observed over Porto AlegreCity during the case and simulated by MM5, would explain the formationof convective clouds. This mechanism would lead to convection formationand depended strongly on the generation of LLJ/MVC at the lowest levelsof the atmosphere, i.e., the influence of the vertical wind shear, the verticalstratification and the vertical decoupling that exists within the nocturnalboundary layer.

Considering the desiccation cracks in the earthen sites,the crack initiation conditions,propagation characteristics and unstable propagation conditions of the desiccation cracks are discussed based on the section of Moon Bay Wall in Sanxingdui. The research results help reveal the cracking law of soil sites and have guiding significance for the engineering practice in earthen sites protection. The drying test is carried out for the soil of Moon Bay Wall. The sample water loss process is recorded by electronic balance. The cracking and expansion process of the crack is obtained with image analysis technology. The displacement field and strain field of the cracking process are obtained by digital image correlation technology. The results show that the surface defects of the sample reduce the tensile stress required for cracking. The smaller the distance between the defect and the boundary,the smaller the critical defect dimension of the crack initiation. Therefore,the crack is more likely to be generated near the boundary of the sample. According to the theory of fracture mechanics,considering the influence of water content on the soil properties,the crack unstable propagation need to meet the condition that the increase rate of stress intensity factor to water content should be greater than the fracture toughness. Theoretically,the calculation method for critical length of crack unstable propagation is derived,and the method is initially verified with measured data. As the water content decreases from 45.6%to 29.1%,the ratio between the critical length of the instability propagation to the width of the sample is reduced from 0.109 to 0.024. The lower the water content,the easier the crack enters the instability stage,and a small defect in the crack can trigger a rapid crack expansion. When protecting the surface of soil sites,the work should focus on repairing large-scale defects distributed in the boundary area of soil layers,should regularly monitor the surface of the soil sites. Once cracking is found,the cracks and their nearby defects should be timely repaired to prevent crack instability expansion.

Watching a Partial Eclipse Which way does the eclipse travel? Relative to Earth, the Moon and Sun are moving at slightly different speeds, which means the Moon’s shadow sweeps across the Earth’s surface from west to east at about 2000 miles an hour, a...

Astronomer and engineer of the first observatory on the Moon. Astronomer and engineer of the first observatory on the Moon.

In an excursus to his article on “The Early Sasanians” in BSOAS., xi, 42 sqq., S. H. Taqizadeh has given a full and illuminating discussion of the Manichæan two-day fasts which preceded the feast of the Bema. All hitherto known about these fasts is contained in a passage in the K. al-Fihrist, 333, 28–334, 1, which runs as follows:—As regards the fasting—(1) when the sun is in Sagittarius and the moon is full, they fast two days without break,(2) then when the New Light appears, they fast two days without break,(3) after this, they fast two days when the moon is full (and the sun is) in Capricornus,(4) then when the New Light appears and the sun is in Aquarius and eight days have passed of the (lunar) month, they fast for thirty days, but break the fast each day at nightfall.

This paper presents a numerical investigation for laminar forced convection flow of a radiating gas in a rectangular duct with a solid element that makes a backward facing step. The fluid is treated as a gray, absorbing, emitting and scattering medium. The governing differential equations consisting the continuity, momentum and energy are solved numerically by the computational fluid dynamics techniques. Since the present problem is a conjugate one and both gas and solid elements are considered in the computational domain, simultaneously, the numerical solution of Laplace equation is obtained in the solid element for temperature calculation in this area. Discretized forms of these equations are obtained using the finite volume method and solved by the SIMPLE algorithm. The radiative transfer equation (RTE) is also solved numerically by the discrete ordinate method (DOM) for computation of the radiative term in the gas energy equation.The streamline and isotherm plots in the gas flow and the distributions of convective, radiative and total Nusselt numbers along the solid-gas interface are presented. Besides, the effects of radiation conduction parameter and also solid to gas conduction ratio as two important parameters on thermo hydrodynamic characteristics of such thermal system are explored. It is revealed that the radiative Nusselt number on the interface surface is much affected by RC parameter but the radiation conduction parameter has not considerable effect on the convective Nusselt number. Comparison between the present numerical results with those obtained by other investigators for the case of non-conjugate problems shows good consistency.

In this thesis I address several topics concerning the interaction of convection and density stratification in oceans and lakes. I present experimental and theoretical investigations of the interaction between a localized buoyancy source and a heat flux through a horizontal boundary, and of the interactions between salt fingers and intermittent turbulence or shear. An extensive series of laboratory experiments were used to quantify the stratification and circulation that result from the combined presence of a localized buoyancy source and a heat flux through a horizontal boundary. Previous studies found that convection in the form of a turbulent buoyant plume tends to produce a stable density stratification, whereas the distributed flux from a horizontal boundary tends to force vigorous overturning and to produce well-mixed layers. A new result of this thesis is that a steady density profile, consisting of a mixed layer and a stratified layer, can exist when the plume buoyancy flux is greater than the distributed flux. When the two fluxes originate from the same boundary, the steady state involves a balance between the rate at which the mixed layer deepens due to entrainment on the one hand and vertical advection of the stratified water far from the plume (due to the volume flux acquired by entrainment) on the other hand. There is a monotonic relationship between the normalized mixed layer depth and flux ratio R (boundary flux/plume flux) for 0 R 1, and the whole tank overturns for R 1. The stable density gradient in the stratified region is primarily due to the buoyancy from the plume and for R 0 there is a small increase in the gradient due to entrainment of buoyancy from the mixed layer. For the case of fluxes from a plume located at one boundary and a uniform heat flux from the opposite boundary the shape of the density profile is that given by Baines & Turner (1969), with the gradient reduced by a factor 1 R due to the heating. Thus, when R 1 there is no stratified region and the whole water column overturns. When 0 R 1, the constant depth of the convecting layer is determined by the Monin-Obukhov scale in the outflow from the plume. One application of these laboratory experiments is to surface cooling in lakes and reservoirs that have shallow sidearms. During prolonged periods of atmospheric cooling, gravity