This article presents a novel design for a Rotational Valve (ROVA) electro-pneumatic (pilot+main) valve combo developed for our rocket RFA ONE, where rotation governs the internal piston movement (in commercial valves, translation is the traditional movement). The need for such a new design comes from two facts: (1) commercial valve design operational pressure at maximum 10bar limits some rocket applications, where higher pressures are used to drive larger purelypneumatic both actuators and valves; (2) dents and scratches cause pistons to get stuck, leading to maintenance downtime and costs. It is the thesis of this study that a valve design employing rotation may alleviate this jamming problem. The 10bar limit problem (emerging from a seal being lift-off due to excessive pneumatic pressure) is resolved by making that seal insensitive to driving pressure. The ROVA valve combo internal operation is explained in detail, being visualized using Computer-Aided Design (CAD) and free to download at an open-source repository. Physical calculations show that the pressurization of internal paths plus the piston’s rotation is achieved with times comparable to commercial valves. This new design pushes the envelop on the electro-pneumatic valve capability to handle larger piloting pressures (that commercial options), and potentially extends valve life by using rotation as a preferred means of operation.
Refrigerant systems, crucial for modern life, are increasingly important due to their environmental impact and rising energy costs, with their advancement influenced by social life evolution and widespread use in homes and buildings. A systematic search using thermodynamic models identified 48 possible ternary mixtures and 5 pure refrigerants. These combinations, based on thermodynamics, could provide energy savings, paving the way for real-world testing and definitive conclusions, not yet studied in literature. REFPROP refers to the reference fluid properties program, developed by NIST version 9.0 for 2010, is a program for calculating the thermodynamic and transport properties of industrially important fluids and their mixtures. This program was used to evaluate the refrigerant properties in different mixing ratios. Then, using the MATLAB version of 2020 apparatus to arrange and solve all the variables to generate the results under set boundary conditions, all the characteristics were incorporated into thermodynamic equations. when compared to R134a, the results demonstrated that mixtures of natural refrigerants usually have acceptable thermal performance; these mixtures may be recommended as suitable replacements for refrigeration and air conditioning systems because they are environmentally harmless and have a low GWP.
Disassembling of a part is required for maintenance of machinery in case. However, the disassembling process is often not explained in the operation manual, or the explanation of the disassembling does not cover all the situations of all the individual parts, even though, such disassembling could be dealt with by operators that are not familiar with the mechanism of machine. Operators themselves have to determine the disassembly process in such a case. Therefore, it is crucial to develop a system that helps inexperienced operators to find out a proper disassembling process. We focus on the disassembling of a specific part referred to as a target part. The approach is based on the positional relation information among the parts. The positional relations matrix that obtained from the contact states of any two parts in all possible directions and can be generated from the ordinary CAD data. This study proposed a method to infer a disassembly process of a specific part based on the positional relation matrix. The method deduces the disassembly process of the target part with the shortest steps, in the condition of one-part-at-a-time manner. We also introduced an integration of disassembling parts based on the obtained process. A case study was conducted and the result confirmed the feasibility of the proposed method; the effectiveness of the integration approach was also demonstrated.
Based on the dynamics, structure and properties of imbedded multi-stack systems, certain functions of the central nervous system (CNS) can be modeled and computer programmed. These models imitate the natural system at some level and can be integrated in future more comprehensive models of the CNS in studies of human movement. Several CNS functions are discussed here. The involvement of the reticular formation (RF) in identifying objects and their properties by touch is addressed. The vision system is discussed in sensing and storage of planar images. The creation of periodic motions for dance or sport is modeled. Mental processing in is the writing or drawing of images is formulated. The touch problem addressed here is the mechanisms to explore, probe, grope and identify an object that is not visible. The object of enquiry may be part of another object, lie under another object or be part of a bigger thing. It may also be involved in the early dynamics of touch in the new-born where the vision dynamics have not yet fully developed. How the central nervous system (CNS) may pursue these tasks is one objective. One elementary attempt is to develop larger structures that can handle CNS functions, how thoughts are formulated, expanded, summarized or abandoned. Multiple Stack System seem to be convenient for handling information flowing from the sensory channels to the cerebrum and the cerebellum. By considering specific tasks, the paper focuses on several functions, connections, and structures that are involved in movement.
This paper is a discussion of computational tools and circuits that deal with the internal and external worlds of the human body. The information processing avenues in the central nervous system (CNS) are an important part of the development. All sensory channels and the vision system are involved. It clarifies the role of the sensory system in internal coordinate systems and for all activities of the CNS. It includes the inherent redundancy aspects of the motor system as well. The visual system is involved in sports such as soccer and basketball and for being aware of and paying attention to both the internal world and the external reality surrounding the athlete.
