Synthesis and Applications of Inorganic/Organic-Polymer Nanocomposites

This research work focuses on developing new synthesis routes to fabricate polymer nanocomposites tailored towards different applications. A simple, one-step method has been devised for synthesizing free-standing, flexible metal nanoparticlepolydimethylsiloxane films. This process simplifies prevalent methods to synthesize nanocomposites, in that here nanoparticles are created in situ while curing the polymer. This route circumvents the need for pre-synthesized nanoparticles, external reducing agents and stabilizers, thereby significantly reducing processing time and cost. The resulting nanocomposite also demonstrates enhancement in mechanical and antibacterial properties, with other envisaged applications in biomedical devices and catalysis. Applying the same mechanism as that used for the formation of bulk metalsiloxane nanocomposites, metal core-siloxane shell nanoparticles and siloxane nanowires were synthesized, with octadecylsilane as the precursor and in situ formed metal nanoparticles (gold, silver) as the catalyst. This method offers some unique advantages over the previously existing methods. This is a room temperature route which does not require high temperature refluxing or the use of pre-synthesized nanoparticles. Furthermore, this synthesis process gives a control over the shape of resulting nanocomposite structures (1-D wires or 0-D spherical particles). High thermal stability of polydimethylsiloxane (PDMS) makes it viable to alternatively synthesize metal nanoparticles in the polymer matrix by thermal decomposition process. This technique is generic across a range of metals (palladium, iron, nickel) and results in nanoparticles with a very narrow size distribution. Membranes 111 with palladium nanopartic1es demonstrate catalytic activity in ethylene hydrogenation reaction. Additionally, a new nanocomposite electrode has been developed for flexible and light-weight Li-ion batteries. Flexible films were prepared by the integration of the poly(vinylidene fluoride-hexafluoropropylene (PVDF-HFP) polymer electrolyte with the three-dimensional (3D), nanostructured electrode composed of aligned carbon nanotube (CNT)-copper oxide hybrid. This hybrid electrode was fabricated by a combination of chemical vapor deposition and electrodeposition techniques. Embedding it in PVDF polymer results in a flexible system and also renders an external separator redundant. This new design shows an improvement in electrochemical performance over pure CNTs as both CNTs and CU20 contribute towards electrochemical activity. Efforts have also been undertaken towards synthesizing synthetic adhesives by mimicking the design principles found in nature. Aligned patterned CNTs have been used to replicate the fibrillar structure found in geckos' toes which generates adhesion through van der Waals forces. The adhesive forces in CNTs were found to be higher than in geckos and the key to this phenomenon lies in the extensive side-wall contact obtained on compressing CNTs against a surface

Push Recovery for Humanoid Robot in Dynamic Environment and Classifying the Data Using K-Mean

Push recovery is prime ability that is essential to be incorporated in the process of developing a robust humanoid robot to support bipedalism. In real environment it is very essential for humanoid robot to maintain balance. In this paper we are generating a control system and push recovery controller for humanoid robot walking. We apply different kind of pushes to humanoid robot and the algorithm that can bring a change in the walking stage to sustain walking. The simulation is done in 3D environment using Webots. This paper describes techniques for feature selection to foreshow push recovery for hip, ankle and knee joint. We train the system by K-Mean algorithm and testing is done on crouch data and tested results are reported. Random push data of humanoid robot is collected and classified to see whether push lie in safer region and then tested on given proposed system

Push Recovery for Humanoid Robot in Dynamic Environment and Classifying the Data Using K-Mean

Push recovery is prime ability that is essential to be incorporated in the process of developing a robust humanoid robot to support bipedalism. In real environment it is very essential for humanoid robot to maintain balance. In this paper we are generating a control system and push recovery controller for humanoid robot walking. We apply different kind of pushes to humanoid robot and the algorithm that can bring a change in the walking stage to sustain walking. The simulation is done in 3D environment using Webots. This paper describes techniques for feature selection to foreshow push recovery for hip, ankle and knee joint. We train the system by K-Mean algorithm and testing is done on crouch data and tested results are reported. Random push data of humanoid robot is collected and classified to see whether push lie in safer region and then tested on given proposed system

Association of risk factors with severity of meibomian gland dysfunction

Background: Meibomian gland dysfunction (MGD) is an alteration in the function of meibomian glands, leading to decreased tear film stability. We aimed to assess the severity of MGD and correlate it with various risk factors. Material and methods: After taking permission from the Institutional Ethical Committee, a prospective observational case-control study was conducted in a tertiary care centre on 100 consecutive patients diagnosed with MGD. After taking informed consent, patients were assessed for the severity of MGD and correlated with risk factors. Results: The mean age of cases and controls was 53.61 ± 14.02 and 50.7 ± 13.0 years, respectively. Watering and heaviness were found to be the most common symptom in patients diagnosed with MGD. A significant correlation was observed between MGD and elderly females, contact lens wearers, smokers, diabetics, excessive use of visual display terminal, rheumatoid arthritis, use of anti-allergics, anti-hypertensive, anti-depressant, and topical antiglaucoma drugs (p < 0.05). Increasing severity of MGD was associated with female sex, serum triglycerides > 150 mg/dL, total cholesterol > 200 mg/dL, serum low-density lipoprotein (LDL) > 130 mg/dL and serum high-density lipoprotein (HDL) > 40 mg/dL. Conclusion: The observations in the study suggest a positive correlation between the severity of MGD and dyslipidemia, a modifiable cardiovascular risk factor. A thorough systemic workup is advisable in patients presenting to an ophthalmologist with severe MGD. Identifying and removing or modifying risk factors aggravating MGD would help alleviate their symptoms and improve their quality of life

Cooperative Adhesion and Friction of Compliant Nanohairs

The adhesion and friction behavior of soft materials, including compliant brushes and hairs, depends on the temporal and spatial evolution of the interfaces in contact. For compliant nanofibrous materials, the actual contact area individual fibers make with surfaces depends on the preload applied upon contact. Using in situ microscopy observations of preloaded nanotube hairs, we show how nanotubes make cooperative contact with a surface by buckling and conforming to the surface topography. The overall adhesion of compliant nanohairs increases with increasing preload as nanotubes deform and continuously add new side-wall contacts with the surface. Electrical resistance measurements indicate significant hysteresis in the relative contact area. Contact area increases with preload (or stress) and decreases suddenly during unloading, consistent with strong adhesion observed for these complaint nanohairs

In situ synthesis of catalytic metal nanoparticle-PDMS membranes by thermal decomposition process

Semi-automated processes are becoming more common within the field of waste management. They are often more efficient and improves the waste operators’ work environment in terms of security and health factors. The French company Veolia, engaged in waste management, has for these reasons developed the Tri Télé-Opéré (TTO) - a system where the direct contact between operator and waste is removed, and the waste is separated via a touch screen. The waste line is currently shown with a series of images in the system. This explorative study investigated how a representation of the line was perceived when using dynamic images on the screen. Diverse sequences with various parameters (viewpoint, direction and pace) were studied in order to observe how they supported the recognition and designation of the operators working with the system. Qualitative results from user tests performed with both novices and waste operators identified parameters that should be considered when using dynamic images of the waste line. The study shows that assembled images captured with an angle of 90°, shown in a slideshow mode are preferred. The viewpoint should furthermore be clear and detailed and the information should be displayed in a direction that corresponds to the long side of the screen, while having a size that make use of the screen surface. Moreover, the results suggest that the pace of the waste line could be increased if parameters allowing good recognition are used simultaneously. This study provides a first insight in how users perceive the TTO with dynamic images and which parameters that could facilitate the work. It is furthermore believed that a further development of this representation of information could ameliorate the future work situation for the waste operators, and thus also the efficiency of the sorting process.Halvautomatiserade processer blir allt vanligare inom området avfallshantering. Det är ofta mer effektiva och förbättrar avfallsoperatörernas arbetsmiljö när det kommer till säkerhet- och hälsoaspekter. Det franska företaget Veolia, som arbetar med insamling och hantering av avfall, har på grund utav detta utvecklat Tri Télé-Opéré (TTO) – ett system där direktkontakten mellan sorterare och avfall har avlägsnats och avfallet istället sorteras via en pekskärm. Systemet visar för tillfället upp avfallslinan med en serie stillbilder. Denna explorativa studie har undersökt hur linan uppfattades med dynamiska bilder på skärmen. Diverse sekvenser med olika parametrar (synvinkel, riktning och hastighet) studerades för att se hur de stödde avfallsoperatörernas igenkänning och klassificering i sorteringen vid skärmen. Kvalitativa resultat från användartest utförda med både nybörjare och avfallsoperatörer identifierade parametrar som bör beaktas när en presentation av avfallslinan med dynamiska bilder används. Studien visar att ett bildspel bestående av bilder tagna med en 90° vinkel föredrogs. Synvinkeln bör vara tydlig och informationen bör visas i en riktning som överensstämmer med skärmens långsida, samt ha en storlek som tar vara på bildskärmens yta. Hastigheten på avfallslinan kan ökas om parametrar som möjliggör ett bra igenkännande används simultant. Denna studie ger en första inblick i hur användarna upplever TTO med dynamiska bilder, och vilka parametrar som skulle kunna underlätta arbetet. En vidareutveckling av denna informationspresentation kan förbättra den framtida arbetssituationen för avfallsoperatörer, och därmed också effektiviteten i sorteringsprocessen