At present, in addition to several thousands of satellites for various applications, there are more than 900,000 pieces from 1 to 10 cm in Earth-orbit. This has been estimated by the European Space Agency (ESA). Furthermore, as time passes, these satellites represent debris. Such accumulated debris threaten the daily uses of space-based applications satellites and future missions. The potential danger would persist unless the international space community considers the risks and join forces to mitigate the danger. Today, only ideas have been proposed by the various space agencies without taking much action. Each of these ideas deals with a specific size of debris. Thus, this paper proposes an integrated design to remedy the situation. It is a satellite with robotic arms, electromagnetic mesh and onboard radar to detect, collect, shred and sort most of the debris larger than 1 cm. This material can, thus, be used as a source of raw material in a novel "made in space program." It can be used as row material for 3d printers for metal and non-metals needed for the maintenance of the International Space Station (ISS) and other equipment of future space missions. This proposal is a premiere design and a start of a pilot model. Also proposed here is a recommendation for a sustainable financing model that can be established by space agencies by assigning a tariff for each future space flight. The tariff value could be determined based on, the extent of the mission's lifetime, the size of the satellite, and the purpose of the mission.
In Duchenne muscular dystrophy (DMD), lack of dystrophin increases the permeability of myofiber plasma membranes to ions and larger macromolecules, disrupting calcium signaling and leading to progressive muscle wasting. Although the biological origin and meaning are unclear, alterations of phosphatidylcholine (PC) are reported in affected skeletal muscles of patients with DMD that may include higher levels of fatty acid (FA) 18:1 chains and lower levels of FA 18:2 chains, possibly reflected in relatively high levels of PC 34:1 (with 16:0_18:1 chain sets) and low levels of PC 34:2 (with 16:0_18:2 chain sets). Similar PC alterations have been reported to occur in the mdx mouse model of DMD. However, altered ratios of PC 34:1 to PC 34:2 have been variably reported, and we also observed that PC 34:2 levels were nearly equally elevated as PC 34:1 in the affected mdx muscles. We hypothesized that experimental factors that often varied between studies; including muscle types sampled, mouse ages, and mouse diets; may strongly impact the PC alterations detected in dystrophic muscle of mdx mice, especially the PC 34:1 to PC 34:2 ratios. In order to test our hypothesis, we performed comprehensive lipidomic analyses of PC and phosphatidylethanolamine (PE) in several muscles (extensor digitorum longus, gastrocnemius, and soleus) and determined the mdx-specific alterations. The alterations in PC 34:1 and PC 34:2 were closely monitored from the neonate period to the adult, and also in mice raised on several diets that varied in their fats. PC 34:1 was naturally high in neonate’s muscle and decreased until age ∼3-weeks (disease onset age), and thereafter remained low in WT muscles but was higher in regenerated mdx muscles. Among the muscle types, soleus showed a distinctive phospholipid pattern with early and diminished mdx alterations. Diet was a major factor to impact PC 34:1/PC 34:2 ratios because mdx-specific alterations of PC 34:2 but not PC 34:1 were strictly dependent on diet. Our study identifies high PC 34:1 as a consistent biochemical feature of regenerated mdx-muscle and indicates nutritional approaches are also effective to modify the phospholipid compositions.
In paved roads, storm water drainage is vital. Poor drainage allows water to remain on road surface for longer time periods, which in turn will negative influences traffic safety and flow efficiency. Furthermore, it can increase the water in gress to pavement layers leading to a significantly rapid deterioration of pavement structure. In straight segments paved roads, pavement cross-slope is essential to drain surface water away from carriageway surface. International and local experiences pro vide typical values for road cross slope to be used for drainage consideration without considering the characteristics of pavement surface or carriageway width. This paper focuses on establishing practical design criteria and CAD simulation that can help in selecting the minimum accepted pavement cross-slope for drainage taking in to consideration the effect of pavement surface conditions, road surface characteristics, and carriageway width.
For more than half a century, asphalt cement used in Egyptian road construction was produced by distillation of crude oils from the fields in the Red Sea area. At the early seventies, the production from the Suez refinery was halted, and asphalt cement was produced from newly discovered crude oil fields in the Egyptian western desert. However, many problems were accompanied by severe creep deformations towards pavement edges and near the median curbs, and Pavement service life dropped from 15 years to about 3 years. This research had studied the effect of adding Crumb Rubber from recycled tires as additive in the mixture by rations 1%, 2%, 3%, 4%, and 5% to bitumen in the asphalt mixture to improve the performance of the waxy asphalt and compare the result with 3 control samples. The optimum bitumen content was determined using the Marshall method. The bitumen range region was set according to each mixture's bitumen demand. The relationship between traffic volume and stability describing the effect of applying the additive by varied ratios will be tabulated, as well as the flow, stability, and penetration values.Using Crumb Rubber from recycled tires as additive used in this study improved the waxy asphalt mixture properties and it is recommended to be used under heavy traffic loads as the marshal stability results show ascending increase from 1029 kg to 1252 kg by increasing the percentage of Crumb Rubber as additive from 1% to 5%. Also, it is recommended in warm weather as the penetration test results show increasing values from 2.96 mm to 3.025 mm and decrease in rutting wheel tracking test value reached 2.2 mm depth at 10000 total Passes.
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