Commissioning Of A Dynamic Mechanical Analyzerfor The Characterization Of Low Temperature Nitife Shape Memory Alloys

NiTiFe shape memory alloys can undergo transformations between cubic, trigonal and monoclinic phases at low temperatures. The low hysteresis associated with the trigonal R-phase transformation make them candidates for actuator applications at low temperatures. However, the literature available on these alloys is limited and there is a need to establish processing structure-property correlations. This study was undertaken with the objective of determining and understanding such correlations in a Ni46.8Ti50Fe3.2 alloy. First, a dynamic mechanical analyzer (DMA) was successfully commissioned to facilitate mechanical testing between -150 and 600ºC. The experiments performed over selected ranges of stress and temperature probed a range of deformation phenomena in these materials. In addition to conventional elastic and dislocation based plastic deformation, also probed were stress-induced formation of the R- and martensite (B19\u27) phases, and twinning in the R- and martensite (B19\u27) phases. Constrained recovery experiments, wherein phase transformations were thermally induced against external loads, were also performed to assess the performance of these alloys in actuator applications. In addition to a DMA, a differential scanning calorimeter, liquid helium dilatometer and a transmission electron microscope were also used. The samples tested were subjected to different thermo-mechanical processing parameters (i.e., percentage of cold work, solutionizing, aging, and annealing time/temperature). Selected combinations of cold work and annealing temperature/times were found to result in narrower transformations (in temperature space), making such alloys of value in cyclic actuator applications. Thus this work contributed to further understand the processing-structure-property relationship in NiTiFe alloys that exhibit the R-phase transformation and in lowering the operating temperature range of shape-memory alloys in order for them to be used in hydrogen related technologies. The immediate benefit to NASA Kennedy Space Center is the development of a shape-memory thermal conduction switch for application in cryogenic liquefaction, densification and zero boil-off systems. This is being extended to include the potential use of shape-memory alloy actuator elements for cryogenic seals, valves, fluid-line repair, self-healing gaskets, and even to ambient debris-less separation and latch/release mechanisms. The financial support of NASA through grant NAG3-2751 is gratefully acknowledged

Remote Medical Emergency Response Through Near-me Area Network

With the advancement in technology, there have been found ways in which even Healthcare can be made readily available. Technologies involving Body Sensor Networks, Wireless Communications and Security in wireless media, have helped to a great extent to make it possible. With this project, we are trying to make remote healthcare readily and quickly available. The secure automatic emergency response system that we develop helps in attending to patients quickly by propagating a help signal to potential healthcare provider. The signal propagates from sensors on a patient till it reaches the nearest Healthcare node and alerts it informing an authentic Healthcare provider near the patient, in case of emergency. For this kind of propagation, we take the help of a Networking technology called the "Near-me Area Network". A Near-me Area Network helps in full duplex communication between nodes in spatial proximity, precisely, sending the readings pulled from Body Sensor on the patient and receiving appropriate help from the healthcare provider. This avoids the need for human intervention from the side of patient in getting help for the health ailment. Given that communication is wireless, and several intermediate nodes are involved in the transmission process, security is an issue. We take care of securing the location and vitals information of the patient by encrypting all the data that is being transmitted. We also try to eliminate duplicate and unauthentic signals by posing a few constraints on the initial signal generation. Our simulation results show that the system determines the presence of a potential Healthcare Provider within 2 minutes and if the presence is positive, healthcare is provided to the patient readily by the identified health official.Computer Scienc

GAMMA: Graspability-Aware Mobile MAnipulation Policy Learning based on Online Grasping Pose Fusion

Mobile manipulation constitutes a fundamental task for robotic assistants and garners significant attention within the robotics community. A critical challenge inherent in mobile manipulation is the effective observation of the target while approaching it for grasping. In this work, we propose a graspability-aware mobile manipulation approach powered by an online grasping pose fusion framework that enables a temporally consistent grasping observation. Specifically, the predicted grasping poses are online organized to eliminate the redundant, outlier grasping poses, which can be encoded as a grasping pose observation state for reinforcement learning. Moreover, on-the-fly fusing the grasping poses enables a direct assessment of graspability, encompassing both the quantity and quality of grasping poses

Local heuristic for the refinement of multi-path routing in wireless mesh networks

We consider wireless mesh networks and the problem of routing end-to-end traffic over multiple paths for the same origin-destination pair with minimal interference. We introduce a heuristic for path determination with two distinguishing characteristics. First, it works by refining an extant set of paths, determined previously by a single- or multi-path routing algorithm. Second, it is totally local, in the sense that it can be run by each of the origins on information that is available no farther than the node's immediate neighborhood. We have conducted extensive computational experiments with the new heuristic, using AODV and OLSR, as well as their multi-path variants, as underlying routing methods. For two different CSMA settings (as implemented by 802.11) and one TDMA setting running a path-oriented link scheduling algorithm, we have demonstrated that the new heuristic is capable of improving the average throughput network-wide. When working from the paths generated by the multi-path routing algorithms, the heuristic is also capable to provide a more evenly distributed traffic pattern

Exploring the interactions of JAK inhibitor and S1P receptor modulator drugs with the human gut microbiome: Implications for colonic drug delivery and inflammatory bowel disease

The gut microbiota is a complex ecosystem, home to hundreds of bacterial species and a vast repository of enzymes capable of metabolising a wide range of pharmaceuticals. Several drugs have been shown to affect negatively the composition and function of the gut microbial ecosystem. Janus Kinase inhibitors and Sphingosine-1-phosphate receptor modulators are drugs recently approved for inflammatory bowel disease through an immediate release formulation and would potentially benefit from targeted colonic targeted delivery to enhance the local drug concentration at the diseased site. However, their impact on the human gut microbiota and susceptibility to bacterial metabolism remain unexplored. With the use of calorimetric, optical density measurements, and metagenomics next-generation sequencing, we show that JAK inhibitors have a minor impact on the composition of the human gut microbiota, while ozanimod exerts a significant antimicrobial effect, leading to a prevalence of the Enterococcus genus and a markedly different metabolic landscape when compared to the untreated microbiota. Moreover, ozanimod is the only drug subject to enzymatic degradation by the human gut microbiota sourced from six healthy donors.. Overall, given the crucial role of the gut microbiome in health, screening assays to investigate the interaction of drugs with the microbiome should be encouraged for the pharmaceutical industry as a standard in the drug discovery and development process

Magnetic and magnetoelectric properties of aurivilliusthree- and four-layered intergrowth ceramics

In this work, we have prepared intergrowth of multiferroic compounds namely Bi4RTi3Fe0.7Co0.3O15-Bi3RTi2Fe0.7Co0.3O12 (BRTFCO15-BRTFCO12) (rare earth (R) = Dy, Sm, La) by solid-state reaction method. From the X-ray diffraction Rietveld refinement, the structure of the intergrowths was found to be orthorhombic in which satisfactory fittings establish the existence of three-layered (space group: b 2 c b) and four-layered compounds (space group: A21am). Analysis of magnetic measurements confirmed a larger magnetization for theSm-modified intergrowth compound (BSTFCO15-BSTFCO12) compared to Dy- and La-doped ones. The emergence of higher magnetic properties can be due to distortion in the unit cell when some Bi3+ ions are replaced with the Sm3+, bonding of Fe3+-O-Co3+ as well as a possible mixture of FexCoy-type nanoparticles that are formed generally in the synthesis of intergrowths. The changes in the magnetic state of the Aurivillius intergrowths have been reflected in the magnetoelectric (ME) coupling: higher ME coefficient (~30 mV/Cm-Oe) at lower magnetic fields and is constant up to 3 kOe. The results were corroborated by Raman spectroscopy and variation of temperature with magnetization data. The results revealed that the RE-modified intergrowth route is an effective preparative method for higher-layer Aurivillius multiferroic ceramics.publishe

Chemical and Biological Investigation of the Antarctic Red Alga \u3cem\u3eDelisea pulchra\u3c/em\u3e

Our interest in the red alga Delisea pulchra (=D.fimbriata) (Greville) Montagne 1844 (Rhodophyceae, Bonnemaisoniales, Bonnemaisoniaceace) was stimulated by its activity in the biosssays done at Wyeth Pharmaceuticals. Halogenated compounds from D. pulchra interfere with Gram-negative bacterial signaling systems, affect the growth of Gram-positive bacteria, inhibit quorum sensing and swarming motility of marine bacteria (inhibit bacterial communication). They also inhibit surface colonization in marine bacteria and exhibit antifouling properties against barnacle larvae and macroalgal gametes. Chemical investigation of D.pulchra collected near Palmer Station, Antarctica yielded three new dimeric halogenated furanones, pulchralide A-C (41-43), along with previously reported fimbrolide (21), acetoxyfimbrolide (22), hydroxyfimbrolide (23) and halogenated ketone 40. The reported Compounds were characterized by comparison of their 1H and 13C NMR data with that previously published. Pulchralide A-C were characterized by both 1D (1H NMR, 13C NMR, DEPT, 1H-1H COSY) and 2D (gHMQC, gHMBC) NMR techniques, supported by HREIMS/HRESIMS data. The absolute stereochemistry of Pulchralide A was determined by a single crystal X-ray analysis. Significant antimicrobial activity was observed in acetoxyfimbrolide (22) and hydroxyfimbrolide (23), where as pulcharlide A (41) and fimbrolide (21) were weakly active

Strategic Freight Transportation Contract Procurement

Auction based market clearing mechanisms are widely accepted for conducting business-to-business transactions. This dissertation focuses on the development of auction mechanism decision tools for freight transportation contract procurement. The dissertation categorizes the problems in freight procurement auctions arising in both sport markets and long term markets. Spot markets are widely employed over the Internet using standard classic auctions. For long-term markets, large shippers (typically manufacturing companies or retailers) have begun to use combinatorial auctions to procure services from trucking companies and logistics services providers. Combinatorial auctions involve very difficult optimization problems both for shippers and carriers. In the US truckload market few carriers have the technical sophistication to develop bids for combinatorial auctions. To address the problem we look at a different auction scheme termed a unit auction, where the shipper can exploit the economies of scope in the network and give the carriers the chance to bid on pre-defined packages similar to 'lotting' in supply chain procurement.The problems in developing contract allocations, called the winner determination problem, are computationally complex and large-scale. Hence the development of good heuristics is of utmost importance. Shippers have non-price business constraints, which must be included in the winner determination problems to closely match shipper business objectives. We develop winner determination problem formulations incorporating the non-price business constraints and develop Lagrangian based optimization methods and greedy approximation algorithms for both unit auctions and combinatorial auctions. Extensive empirical results are provided to test the performance of the heuristics against a standard integer-programming solver.Bidding in auctions from the carrier's perspective is complicated as it involves taking into account the competitive behavior of other carriers and a carrier's difficult network optimization problems. We develop bidding strategies for carriers in spot markets using concepts from economic auction theory. For long-term market bidding, we study the effects of demand uncertainty, competitive behavior, carrier network synergies and strategic pricing, and shipper's winner determination problems on carrier bidding using optimization-based simulation analysis