Investigation of tape flexures for space borne deployable structures

2021 ◽  
pp. 095605992110640
Author(s):  
Hemant Arora ◽  
Rutvik Dangarwala ◽  
Sudipto Mukherjee ◽  
Bhavdeep Singh Munjal
Keyword(s):  
State Of The Art ◽  
Launch Vehicles ◽  
Comparison Study ◽  
Deployable Structures ◽  
Suitable Candidate ◽  
Large Size ◽  
High Bandwidth ◽  
Interplanetary Missions ◽  
Monolithic Structures ◽  
Practical Feasibility

Space exploration arises the demand for launching large size structures to satisfy the need of high bandwidth telecommunication, earth observation and deep space interplanetary missions. Launching of these monolithic structures of sizes 3 m or more are not feasible due to limited launch fairing space of state-of-the-art launch vehicles. Therefore, the development of innovative deployment mechanisms is need of the hour. Deployment process of space borne deployable systems is the process of transition from mechanism to structure which is one of the unreliable stage due to existence of many conventional rotary joints which causes loss of energy due to backlash, friction and misalignment. An investigation study is presented in this paper for churning out a solution of flexible hinges using tape springs in state-of-the-art space deployable configurations which eliminates the factors causing loss of energy. Analytical and experimental methods are evaluated for investigating the bending behaviour of tape flexures. Tape flexures demonstrate to be a suitable candidate for compliant deployable configuration. The proposed configuration with combination of two tape flexures mounted in such a way that concave curve of each tape faces each other are structurally analysed for desired rotation angle. A comparison study is carried out for various material options of single and double layered tape flexures proposed for a flexure hinge. Practical feasibility of the proposed configuration is also demonstrated successfully on space borne deployable structures.

Chitosan Nanoparticles: An Approbative System for the Delivery of Herbal Bioactives

2020 ◽  
Vol 10 ◽  
Author(s):  
Sapna Saini ◽  
Sanju Nanda ◽  
Anju Dhiman
Keyword(s):  
Drug Delivery ◽  
Drug Delivery Systems ◽  
State Of The Art ◽  
Chitosan Nanoparticles ◽  
Delivery Systems ◽  
Intrinsic Properties ◽  
Amino Groups ◽  
Suitable Candidate ◽  
Film Forming ◽  
Novel Drug

: Chitosan, a natural biodegradable polymer obtained from deacetylation of chitin, has been used as an approbative macromolecule for the development of various novel drug delivery systems. It is one of the most favorable biodegradable carriers for nanoparticulate drug delivery due to its intrinsic properties, such as biocompatibility, biodegradability, non-toxicity, availability of free reactive amino groups, and ease of chemical modification into different active derivatives. Furthermore, interesting physical properties (film-forming, gelling and thickening) make it a suitable candidate for formulations, such as films, microcapsules, beads, nanoparticles, nanofibres, nanogel and so on. Researchers have reported that chitosan nanoparticles act as a promising vehicle for herbal actives as they provide a superior alternative to traditional carriers and improve pharmaceutical efficiency. As no review of chitosan nanoparticles encapsulating herbal extracts and bioactives has been published till date, a maiden effort has been made to collate and review the use of chitosan nanoparticles for the entrapment of phytoconstituents to yield stable, efficient and safe drug delivery systems. Additionally, the paper presents a comprehensive account of the state-of the-art in fabricating herbal chitosan nanoparticles and their current pharmacological status. A list of patents on chitosan nanoparticles of herbal actives has also been included. This review is intended to serve as a didactic discourse for the formulation scientists endeavoring to develop advanced delivery systems for herbal actives.

scholarly journals Recent Developments in Coatings, Gratings, and Reflective Components

1984 ◽  
Vol 79 ◽  
pp. 607-616
Author(s):  
R. R. Shannon
Keyword(s):  
State Of The Art ◽  
New Technology ◽  
The State ◽  
Current Technology ◽  
Large Size ◽  
Incoming Radiation ◽  
Recent Developments ◽  
Electronic Sensors ◽  
Large Primary ◽  
Telescope System

The requirements on gratings and coatings for astronomical use differ from the general industrial requirements primarily in the scale of the components to be fabricated. Telescopes have large primary mirrors which require large coating plants to handle the components. Dispersive elements are driven by the requirement to be efficient in the presence of large working apertures, and usually optimize to large size in order to efficiently use the incoming radiation. Beyond this, there is a “new” technology of direct electronic sensors that places specific limits upon the image scale that can be used at the output of a telescope system, whether direct imagery or spectrally divided imagery is to be examined. This paper will examine the state of the art in these areas and suggest some actions and decisions that will be required in order to apply current technology to the predicted range of large new telescopes.

Elemental analysis of lithium ion batteries

2017 ◽  
Vol 32 (10) ◽  
pp. 1833-1847 ◽  
Author(s):  
Sascha Nowak ◽  
Martin Winter
Keyword(s):  
Energy Storage ◽  
Lithium Ion Batteries ◽  
Elemental Analysis ◽  
State Of The Art ◽  
Electronic Devices ◽  
Lithium Ion ◽  
Promising Candidate ◽  
Decomposition Products ◽  
Power Sources ◽  
Large Size

Being successfully introduced into the market only 25 years ago, lithium ion batteries are already state-of-the-art power sources for portable electronic devices and the most promising candidate for energy storage in large-size batteries. Therefore, elemental analysis of lithium ion batteries (lithium ion batteries), their components and decomposition products is a fast growing topic in the literature.

scholarly journals Ad Hoc Vehicle Networks: Recapitulation and Challenges

2021 ◽  
Vol 10 (1) ◽  
pp. 45-52
Author(s):  
S. Neelambike ◽  
C. Amith Shekhar ◽  
B. H. Rekha ◽  
Bhavana S. Patil
Keyword(s):  
Network Security ◽  
Network Design ◽  
Routing Protocols ◽  
Ad Hoc ◽  
State Of The Art ◽  
Individual Privacy ◽  
High Bandwidth ◽  
Vehicle Networks ◽  
Signal Modelling

Being ad-hoc in design, VA NET is a form of networks generated by the idea of building up a network of cars for a specific needs or circumstance. In addition to the benefits, VANET poses a large number of challenges such as providing QoS, high bandwidth and connectivity, and vehicle and individual privacy security. Each report discusses VANET 's state-of-the-art, explaining the relevant problems. We address in depth network design, signal modelling and propagation mechanisms m, usability modeling, routing protocols and network security. The paper's key results are that an effective and stable VANET satisfies all architecture criteria such as QoS, minimal latency, low BER and high PDR. At the end of the paper are addressed several primary work areas and challenges at VANET.

scholarly journals Enriching Ontology-based Data Access with Provenance

2019 ◽  
Author(s):  
Diego Calvanese ◽  
Davide Lanti ◽  
Ana Ozaki ◽  
Rafael Penaloza ◽  
Guohui Xiao
Keyword(s):  
State Of The Art ◽  
Data Access ◽  
Heterogeneous Data ◽  
Data Sources ◽  
Conjunctive Query ◽  
Heterogeneous Data Sources ◽  
Idempotent Semirings ◽  
Database Theory ◽  
Extensive Evaluation ◽  
Practical Feasibility

Ontology-based data access (OBDA) is a popular paradigm for querying heterogeneous data sources by connecting them through mappings to an ontology. In OBDA, it is often difficult to reconstruct why a tuple occurs in the answer of a query. We address this challenge by enriching OBDA with provenance semirings, taking inspiration from database theory. In particular, we investigate the problems of (i) deciding whether a provenance annotated OBDA instance entails a provenance annotated conjunctive query, and (ii) computing a polynomial representing the provenance of a query entailed by a provenance annotated OBDA instance. Differently from pure databases, in our case, these polynomials may be infinite. To regain finiteness, we consider idempotent semirings, and study the complexity in the case of DL-LiteR ontologies. We implement Task (ii) in a state-of-the-art OBDA system and show the practical feasibility of the approach through an extensive evaluation against two popular benchmarks.

Evaluation on Microstructure and Mechanical Properties of Welded Joints by GMAW in UNS N10003 Alloy

2017 ◽  
Author(s):  
Kun Yu ◽  
Zhenguo Jiang ◽  
Xianwu Shi ◽  
Chaowen Li ◽  
Shuangjian Chen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Arc Welding ◽  
Welded Joint ◽  
Gas Metal Arc Welding ◽  
Suitable Candidate ◽  
Gas Tungsten Arc ◽  
Large Size ◽  
Metal Arc Welding ◽  
Nickel Base ◽  
Thorium Molten Salt Reactor

UNS N10003 alloy is a primary material of the Thorium Molten Salt Reactor (TMSR) in China that is a suitable candidate reactor of the Generation IV nuclear reactors. Gas metal arc welding (GMAW) is more effective than gas tungsten arc welding (GTAW) which is usually used to weld nickel-base alloys. In order to improve welding efficiency, it is necessary to weld nickel-base alloys using GMAW. The purpose of this work is to evaluate effect of GMAW on microstructure evolution and mechanical properties in UNS N10003 alloy. The results of microstructure showed that the sound welded joint without hot cracking can be obtained, although quantities of M6C-γ eutectic phases with large size were precipitated in fusion zone (FZ) and transformed in heat affected zone (HAZ) because of element segregation. The results of microhardness test indicated that there was no softened zone in the welded joint. The results of tensile test at room temperature and high temperature showed that the short-term time-independent strength was not damaged by the formation of large M6C-γ eutectic phases.

State of the Art and Analysis of Design for Assembly of Large and Heavy Parts

2013 ◽  
Vol 572 ◽  
pp. 253-256
Author(s):  
Hanna Leslye García-Guerra ◽  
Jesús Manuel Dorador-González
Keyword(s):  
State Of The Art ◽  
Future Research ◽  
Design For Assembly ◽  
Design Features ◽  
Total Cost ◽  
Large Size ◽  
Manufactured Products ◽  
Size Constraints ◽  
Components Analysis ◽  
Product Assembly

Design For Assembly (DFA) is a tool to evaluate the design of parts and the products assemblability. Additionally, DFA is a key tool to reduce both cost and assembly time. DFA includes a set of techniques and procedures that, when applied properly, makes the product assembly more efficient. Assembly takes between 20% and 60% of production time, and represents between 25% and 75% of the total cost of the manufactured products. Existing techniques consider weight and size restrictions to assess the design features of the products. All those components not considered within the weight and size constraints are qualified in equal way. For the scope of this research large and heavy parts are defined as parts that measure above one meter and weight from five kilograms to five tons. Most products of large size have assemblies and subassemblies. Additionally there are a number of processes for handling an assembly of large and heavy components. Despite the information identified, further research focused to improve the knowledge in assembly methods is needed. This paper presents the state of-the-art in the assembly of large and heavy components analysis and to be a reference for future research.

scholarly journals Nonlinear Current Control for Reluctance Actuator with Hysteresis Compensation

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Yu-Ping Liu ◽  
Kang-Zhi Liu ◽  
Xiaofeng Yang
Keyword(s):  
High Speed ◽  
Heat Dissipation ◽  
Current Control ◽  
Strong Nonlinearity ◽  
Suitable Candidate ◽  
Hysteresis Compensation ◽  
Large Size ◽  
High Acceleration ◽  
Control Configuration ◽  
The Voice

The next-generation fine stage of the wafer scanner needs a suitable actuator to meet the requirements of high speed, high acceleration, and high precision. The voice coil actuator is no longer the best choice because of its large size and the heat dissipation is difficult to solve. The reluctance actuator can provide a big force based on a unique property of small volume and low current, making it a very suitable candidate. But the strong nonlinearity such as the hysteresis between the current and force limits the reluctance actuator applications in nanometer positioning. This paper proposes a nonlinear current control configuration with hysteresis compensation using the adaptive multilayer neural network. Simulation results show that the hysteresis compensator is effective in overcoming the hysteresis and is promising in precision control applications.

scholarly journals A Modern Approaches for Modeling Time-Varying Database Models

2019 ◽  
pp. 25-32
Author(s):  
NASHWAN ALROMEMA ◽  
FAHAD ALOTAIBI
Keyword(s):  
State Of The Art ◽  
Research Work ◽  
Ease Of Use ◽  
Time Varying ◽  
Comparison Study ◽  
Database Applications ◽  
Modeling Approaches ◽  
Monitoring Applications ◽  
Different Types ◽  
Database Models

Time-varying data models store data related to time instances and offer different types of timestamping. These modeling approaches are considered as one of the most important parts of many database applications like metrological, banking, biomedical, accounting, scheduling, reservation systems, sensor based systems, real-time monitoring applications and applications involving maintenance of huge records. This research work introduces the state-of-the-art modeling approaches of Time-varying data. Furthermore we will show how to represent a running example using different approaches and give a comparison study of storage, and the ease of use of each model.

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