1,964 research outputs found
Crowdsourced Delivery with Drones in Last Mile Logistics
We consider a combined system of regular delivery trucks and crowdsourced drones to provide a technology-assisted crowd-based last-mile delivery experience. We develop analytical models and methods for a system in which package delivery is performed by a big truck carrying a large number of packages to a neighborhood or a town in a metropolitan area and then assign the packages to crowdsourced drone operators to deliver them to their final destinations. A combination of heuristic algorithms is used to solve this NP-hard problem, computational results are presented, and an exhaustive sensitivity analysis is done to check the influence of different parameters and assumptions
The Impact of Operating Parameters on the Gas-Phase Sulfur Concentration after High Temperature Sulfur Sorption on a Supported Mo-Mn Sorbent
The impact of operating parameters on H2S capture from a syngas mixture by a Mo-promoted Mn-based high-temperature sorbent was investigated. The parameters investigated included temperature, space velocity, H2S concentration in the feed gas, and steam content. The H2S and SO2 concentrations in the gas after passing over a bed of the sorbent were analyzed and compared with thermodynamic calculations. The results confirmed that low temperature, low space velocity, low H2S concentration, and a dry feed were favorable for achieving a low residual concentration of sulfur compounds in the effluent gas. The sorbent was able to reduce the residual H2S concentration to below 1 ppm under all tested conditions. However, the unavoidable steam content in the gas phase had a significant adverse effect on sulfur removal from the gas. An empirical model, containing the three variables, i.e., temperature, space velocity, and H2S concentration in the feed, was developed and can be used to predict the effluent H2S residual concentration after treatment by the 15Mn8Mo sorbent.publishedVersio
Optimization of the fermentation media, mathematical modeling, and enhancement of paclitaxel production by Alternaria alternata after elicitation with pectin
Alternaria alternata fungus is a potent paclitaxel producer isolated from Corylus avellana. Themajor challenge is the lack of optimized media for endophytic fungi productivity. In the effort tomaximize the production of taxoids by A. alternata, several fermentation conditions, including pH(pH 4.0–7.0), different types and concentrations of carbon (fructose, glucose, sucrose, mannitol,sorbitol, and malt extract), and nitrogen (urea, ammonium nitrate, potassium nitrate, ammoniumphosphate, and ammonium sulfate) were applied step by step. Based on the results, A. alternata in amedium containing sucrose 5% (w/v) and ammonium phosphate 2.5 mM at pH 6.0 showed a rapid andsustainable growth rate, the highest paclitaxel yield (94.8 μg gFW−1 vs 2.8 μg gFW− 1 in controls), andthe maximum content of amino acids. Additionally, the effect of pectin was evaluated on fungus, andmycelia harvested. Pectin significantly enhanced the growth and taxoid yield on day 21 (respectively171% and 116% of their corresponding on day 7). The results were checked out by mathematicalmodeling as well. Accordingly, these findings suggest a low-cost, eco-friendly, and easy-to-produceapproach with excellent biotechnological potential for the industrial manufacture of taxoids.</p
Investigations of molybdenum-promoted manganese-based solid sorbents for H2S capture
The promotion effect of Mo-addition to alumina-supported Mn-based sorbents for high-temperature desulphurization was explored. A series of Mn-based sorbents with fixed Mn-loading and different Mo-loadings were prepared by the wet impregnation method and both fresh and used sorbents were characterized with respect to their physical and chemical properties. The sorbents were active for H2S removal at 600 °C and could be regenerated by oxidation in diluted air. The sorbents were subjected to 10 repeated sorption/regeneration cycles, and some loss of capacity occurred during the cycles. The results show that Mo-addition promotes the Mn-based sulfur sorbent performance both in terms of capacity and stability. Over the range investigated (0–8 wt% Mo added to a 15 wt% Mn sorbent), the improvement increased with an increasing amount of Mo added. The sample with the highest Mo-addition (15Mn8Mo) also retained the capacity best, as over 90% of the capacity remained after 10 sorption-regeneration cycles, in spite of suffering the most from sintering (observed as loss in surface area, increased pore size, and growth in Mn particle size). Characterization of the fresh and used samples using XRD and Raman spectroscopy indicates that a mixed Mn–Mo oxide suggested to be MnMoO4 plays a role in the promotion mechanism. The sorbent, 15Mn8Mo, is suggested to be promising for high-temperature desulphurization of bio-syngas.publishedVersio
Investigating the Efficiency of Tejarat Bank Information Systems in Presenting Reports to the Managers
This study aims to investigate the efficiency of Tejarat Bank information systems and the extent to which bank managers apply these systems. Today's condition of trading and competitive atmosphere and the evolution in financial and banking systems of countries has highlighted the need for a comprehensive and responsive evolution to satisfy the society's needs in any developing and sustainable economy. Hypotheses have been formulated to assess and evaluate the present systems from various dimensions. This study was carried out in all branches of Tejarat Bank in Kerman Province in 2014. Data was collected through questionnaire and field study. Data analysis have been done through statistical tests. Findings showed that Tejarat Bank accounting information system has great potentiality and efficiency in providing the bank managers with adequate information. On the other side, the bank mangers made the least use of the information presented by these systems
Scalable rekeying algorithm in IEEE 802.16e
IEEE 802.16e standard provides wide coverage and high bandwidth for subscribers in a metropolitan area network. It introduces Multicast and Broadcast Rekeying Algorithm (MBRA) which is a multicasting scheme to communicate with many users concurrently. Although ELAPSE (for Efficient sub-Linear rekeying Algorithm with Perfect SEcrecy) improves on the deficiencies of MBRA, the algorithm poorly responds to scalability issue. This paper proposes a Scalable Rekeying Algorithm (SRA) based on a complete binary tree structure. SRA is introduced with linear linked list structure in order to make the system more scalable. Evaluation analysis shows that SRA manages to improve the scalability issue in MBRA for Mobile WiMAX
Smart-substrate: a novel structural design to avert residual stress accretion in directed energy deposition additive manufacturing
Residual stresses, related distortions and cracks are detrimental in metallic Additive Manufacturing (AM). Previously developed stress-control strategies based on reducing thermal gradients hardly diminish the stress concentrations at the built basement and easily affect other physical phenomena involved in AM. To overcome this, a novel strategy, named as Smart-Substrate, consisting of optimising the inner structure and local stiffness of the substrate is proposed to avert stress accretion and related part deformations. To demonstrate its advantages, a coupled thermomechanical finite element model for AM, experimentally calibrated with in-situ temperature and displacement measurements, is employed to analyse the thermal and mechanical behaviour of three groups of different structures with increasing geometrical complexity (single-wall, rectangular and block parts) fabricated by Directed Energy Deposit (DED) on the standard and smart substrates, respectively. Through using Smart-Substrate, the generation of residual stresses, especially the stress concentrations at the bottom corner of DED-builds being highly sensitive to cracks, and the induced deflections, are fundamentally throttled, and contrariwise for the standard substrate. More importantly, the use of Smart-Substrate is almost without prejudice to the temperature field, metallurgy and resulting mechanical hardness. This provides a possibility for addressing different physical problems individually, enlarging the AM process window.This work was supported by National Key R&D Programs of China: [grant numbers 2016YFB1100602 & 2016YFB1100100]; European KYKLOS 4.0 project: [grant number 872570]; China Scholarship Council: [grant number 201906290011].Peer ReviewedPostprint (published version
Bis[μ-4-(2-oxidobenzylidene)thiosemicarbazidato-κ4 S,N 1,O:O]bis[(pyridine-κN)zinc]
In the title compound, [Zn2(C8H7N3OS)2(C5H5N)2], the Zn2O2 ring has a flattened roof shape, with the roof angle equal to 10.10 (6)°. The thiosemicarbazones act as tridentate ligands to one ZnII atom, with the O atoms additionally in bridging positions to the second ZnII atom. Both ZnII atoms are five-coordinated; the coordination polyhedra are close to square pyramids, with the pyridine N atoms at apical positions. Two intermolecular N—H⋯N and one relatively weak N—H⋯S hydrogen bond, together with C—H⋯S weak interactions, connect the molecules into a three-dimensional network
Patrol team language identification system for DARPA RATS P1 evaluation
This paper describes the language identification (LID) system developed by the Patrol team for the first phase of the DARPA RATS (Robust Automatic Transcription of Speech) program, which seeks to advance state of the art detection capabilities on audio from highly degraded communication channels. We show that techniques originally developed for LID on telephone speech (e.g., for the NIST language recognition evaluations) remain effective on the noisy RATS data, provided that careful consideration is applied when designing the training and development sets. In addition, we show significant improvements from the use of Wiener filtering, neural network based and language dependent i-vector modeling, and fusion
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