61 research outputs found
Enhanced Oil Recovery using Carbonated Polymeric Nanofluids : A New Age Approach to CO2 Utilization and Corrosion Mitigation
No full textThe author would like to thank the CIF facility and its staff, including Mr. Anuj Prajapati, Mr. Zahoor Alam, and Mr. Brijesh. Thanks are also extended to all the members associated with the work.Peer reviewe
Developing E. coli-E. coli co-cultures to overcome barriers of heterologous tryptamine biosynthesis
No full textTryptamine is an alkaloid compound with demonstrated bioactivities and is also a precursor molecule to many important hormones and neurotransmitters. The high efficiency biosynthesis of tryptamine from inexpensive and renewable carbon substrates is of great research and application significance. In the present study, a tryptamine biosynthesis pathway was established in a metabolically engineered E. coli-E. coli co-culture. The upstream and downstream strains of the co-culture were dedicated to tryptophan provision and conversion totryptamine, respectively. The constructed co-culture was cultivated using either glucose or glycerol as carbon source for de novo production of tryptamine.The manipulation of the co-culture strains’ inoculation ratio was adapted to balance the biosynthetic strengths of the pathway modules for bioproduction optimization. Moreover, a biosensor-assisted cell selection strategy was adapted to improve the pathway intermediate tryptophan provision by the upstream strain, which further enhanced the tryptamine biosynthesis. The resulting biosensor-assisted modular co-culture produced 194mg/L tryptamine with a yield of 0.02 g/g glucose using shake flask cultivation.The findings of this work demonstrate that the biosensor-assisted modular co-culture engineering offers a new perspective for conducting microbial biosynthesis.Peer reviewe
Design and Governance of Platforms to leverage an ecosystem of complementors
No full textThis paper analyzes how specific aspects of design and governance of platform explain complementors participation in the video game console industry. This study introduces a new dimension to measure platform openness and suggest that by opening the platform vertically to different markets, platform firms can smoothen complementors competition and incentivize them to participate in their network. This study makes a first attempt to measure platform boundary resources and highlight its positive influence on complementors participation. Finally, the analysis also explores conditions under which signing an exclusive contract is beneficial for complementors. Complementors tend to participate in exclusive contracts during the early stages of platform rather than mature stages due to intense competition among complementors in the latter stage. The results suggest that by following the correct design and governance strategies, platform firms can orchestrate a large network of complementors and proliferate a variety of complementary product offerings
he Creators A Look at the Changing Work of Potters and the Future of Their Craft in Thimi, Nepal
No full textThe Newari sur-name Prajapati has been associated with those who are of the potter caste in the Kathmandu valley. In the past 30 years ceramics in the historic pottery town of Thimi has changed drastically from being an essential and necessary craft and the only occupation for Prajapatis, to a struggling population of visually aging potters. This paper examines the workshop Everest Pottery in Thimi nepal as a case study for the state of ceramics in Thimi today. The author traces the origins of the workshop\u27s founder Shiva Prajapati and examines the shift that Shiva made from traditional Newari pottery practices to modern techniques. The author discusses the success of Everest Pottery and the shift of their market from local to global. The author concludes that with the rise of aluminum, plastic and the fact that Nepali\u27s are no longer looking to buy terracotta pots, the traditional forms that have inhabited the houses of the Kathmandu Valley for generations may be all but gone in the next few years. As a secondary focus the author discovered that while Everest Pottery has left behind most traditional Newari pottery practices, Newari traditional values and customs remain present in the workplace and can be witnessed through the stark division of labor by gender. The women of Everest Pottery all have different stories of how they came to work in ceramics. The author discusses the stories of the women of Everest Pottery, their perceptions of their own roles in ceramics and the perceptions of the female role from the point of view of the men of Everest Pottery. The author found that while there is no spoken rule against women throwing on the wheel, even in a modern ceramic workshop, this tradition remains. Most women who learned to throw in their youth stop throwing when they get married, and additionally do not want to try again for fear that it is too difficult. Similarly, the men of Everest Pottery express doubts about women\u27s ability to throw due to their lack of strength. While the women of Everest Pottery seem to be happy with the status quo, the author offers a counter observation that while some women aren\u27t interested in the wheel, the ones that are given no space to learn. Additionally the author offers potential futures for ceramics if women are eventually included in this integral part of the process
ALPHAPROG: Reinforcement Generation of Valid Programs for Compiler Fuzzing
No full textFuzzing is a widely-used testing technique to assure software robustness. However, automatic generation of high-quality test suites is challenging, especially for software that takes in highly-structured inputs, such as the compilers. Compiler fuzzing remains difficult as generating tons of syntactically and semantically valid programs is not trivial. Most previous methods either depend on human-crafted grammars or heuristics to learn partial language patterns. They both suffer from the completeness issue that is a classic puzzle in software testing. To mitigate the problem, we propose a knowledge-guided reinforcement learning-based approach to generating valid programs for compiler fuzzing. We first design a naive learning model which evolves with the sequential mutation rewards provided by a target compiler we test. By iterating the training cycle, the model learns to generate valid programs that can improve the testing efficacy as well. We implement the proposed method into a tool called ALPHAPROG. We analyze the framework with four different reward functions and our study reveal the effectiveness of ALPHAPROG for compiler testing. We also reported two important bugs for a compiler production that were confirmed and addressed by the project owner, which further demonstrates ALPHAPROG's applied value in practice
Effect of Li<sup>3+</sup> Ion Irradiation on Ionic Transport Properties of Complexed Polymer Electrolytes
No full textAbstractSwift heavy ion (SHI) irradiation effects on ionic conduction in the PVA-H3PO4 polymer electrolyte films have been investigated due to its variety of applications in electrochemical devices. Polymer electrolytes films are irradiated with 50 MeV Li3+ ions having five different fluences viz. 5x1010, 1011, 5x1011, 1012 and 5x1012 ions/cm2. It is observed that irradiation of the polymer electrolyte films with swift heavy ions shows enhancement in conductivity at lower fluences and decrease in conductivity at higher fluences. It appears that below the critical fluence, swift heavy ion irradiation increases the diffusivity of Li+ ion in the polymer electrolyte which provides larger pathways for ionic transport throughout the system. The temperature dependence of electrical conductivity variation has been used to compute the activation energy involved in conduction process.</jats:p
DeepFuzz: Automatic Generation of Syntax Valid C Programs for Fuzz Testing
No full textCompilers are among the most fundamental programming tools for building software. However, production compilers remain buggy. Fuzz testing is often leveraged with newlygenerated, or mutated inputs in order to find new bugs or security vulnerabilities. In this paper, we propose a grammarbased fuzzing tool called DEEPFUZZ. Based on a generative Sequence-to-Sequence model, DEEPFUZZ automatically and continuously generates well-formed C programs. We use this set of new C programs to fuzz off-the-shelf C compilers, e.g., GCC and Clang/LLVM. We present a detailed case study to analyze the success rate and coverage improvement of the generated C programs for fuzz testing. We analyze the performance of DEEPFUZZ with three types of sampling methods as well as three types of generation strategies. Consequently, DEEPFUZZ improved the testing efficacy in regards to the line, function, and branch coverage. In our preliminary study, we found and reported 8 bugs of GCC, all of which are actively being addressed by developers
Low-fat sweet syrup cheese ball (Rosogolla) manufacturing and effect of lowering fat on quality
No full textStructural and electrical characterization of plasticized PVA: AgI polymer electrolyte
No full textAbstract
The development of new polymeric systems with high ionic conductivity is one of the main objectives in the field of polymer materials with application point of view. In the present work, Ag+ion conducting solvent free composite polymer electrolyte thin films have been prepared using polyvinyl alcohol (PVA) as host polymer and polyethylene glycol (PEG) as plasticizer by standard solution cast technique. The structural characteristics of the prepared films have been obtained from X-ray diffraction (XRD) patterns. Maximum room temperature ionic conductivity of order of 10-5S cm-1 is obtained using complex admittance (B-G) spectroscopy. The temperature dependent conductivity shows two distinct regions of Arrhenius type thermally activated behavior before and after glass transition temperature. Dielectric constant, ε′ and dielectric loss, ε″ of the samples increases with temperature which is similar in behavior as that of conductivity. The activation energy for ion conduction has been calculated from temperature dependent conductivity curve and its minimum value is found to be 0.30 eV for PVA-PEG-20% AgI polymer electrolyte sample. High value of transference number shows that samples are ionic in nature which is confirmed by Wagner’s polarization technique.</jats:p
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