599 research outputs found
Leaving Gondwana:the changing position of the Indian subcontinent in the global faunal network
Get PDFThe paleogeographic history of the Indian subcontinent is unique among Earth’s landmasses. From being part of the southern supercontinent Gondwana for most of the Mesozoic, through a period of isolation as a drifting entity in the Late Cretaceous, to colliding with Asia near the Paleocene-Eocene boundary, the Indian subcontinent has been associated with, and dissociated from, a variety of landmasses. This paleogeographic history has been invoked to explain aspects of the subcontinent’s modern-day fauna, with a combination of endemic radiations, remnants from Gondwana, and more recent immigrants from Laurasia. Here, network approaches document how vertebrate faunas of the Indian subcontinent, and specifically their relationships to those of other landmasses, changed during the subcontinent’s isolation from close faunal relationships with Madagascar and South America in the Late Cretaceous to a more Laurasian fauna most similar to those of Europe by the Eocene
Comparison of Preparation Methods of Copper Based PGMFree Diesel-Soot Oxidation Catalysts
Get PDFCuO-CeO2 systems have been proposed as a promising catalyst for low temperature diesel-soot oxidation.
CuO-CeO2 catalysts prepared by various methods were examined for air oxidation of the soot in a semi
batch tubular flow reactor. The air oxidation of soot was carried out under tight contact with soot/catalyst
ratio of 1/10. Air flow rate was 150 ml/min, soot-catalyst mixture was 110 mg, heating rate was 5 0C/min.
Prepared catalysts were calcined at 500 0C and their stability was examined by further heating to 800 0C
for 4 hours. It was found that the selectivity of all the catalysts was nearly 100% to CO2 production. It was
observed that the activity and stability of the catalysts greatly influenced by the preparation methods. The
strong interaction between CuO and CeO2 is closely related to the preparation route that plays a crucial
role in the soot oxidation over the CuO-CeO2 catalysts. The ranking order of the preparation methods of
the catalysts in the soot oxidation performance is as follows: sol-gel > urea nitrate combustion > Urea
gelation method > thermal decomposition > co-precipitatio
The Cajal body protein p80-coilin forms a complex with the adenovirus L4-22K protein and facilitates the nuclear export of adenovirus mRNA
Get PDFABSTRACT Cajal bodies (CBs) are major sub-nuclear structures in most eucaryotic cells. In human adenovirus 5 (Ad5) infection, CBs are reorganized into microfoci in the late phase of infection. Here we show that many CB protein components (p80-coilin, SMN-1, and WRAP53) remained stable throughout most of the infectious cycle of Ad type 5 (Ad5) in human A549 epithelial cells, even when CBs were reorganized into microfoci. Reduction of p80-coilin expression by RNA interference resulted in significant reductions in the levels of early (E1A, E2A-DBP), intermediate (pIX and IVa2), and late (L1-IIIa, L2-penton base, L3-hexon, L4-100K, and L5-fiber) proteins in Ad5-infected A549 cells. Depletion of p80-coilin did not significantly alter the total cellular levels of the corresponding Ad cytoplasmic mRNAs (with the exception of E1A 12S and 13S and pIX mRNA) or the production of the Ad5 pre-mRNAs tested (E1A, E2A-DBP, IVa2, or late pre-mRNAs containing the tripartite leader). However, the ratio of viral cytoplasmic to nuclear-spliced Ad RNAs was reduced in p80-coilin-depleted, Ad5-infected cells compared to control-infected cells. Immunofluorescent staining of Ad5-infected cells revealed co-localization of p80-coilin with areas of immunoreactivity defined by a polyclonal antibody that recognized the L4-22K and L4-33K proteins in a fraction of microfoci. Immunoprecipitation analysis showed that only the L4-22K protein formed a stable complex with p80-coilin in Ad5-infected cells and in cells co-transfected with plasmids encoding p80-coilin and either the L4-22K or L4-33K protein. p80-coilin therefore plays an important role in Ad replication by complex formation with L4-22K and facilitating nuclear export of Ad mRNAs. IMPORTANCE The architecture of sub-nuclear structures of eucaryotic cells is often changed during the infectious cycle of many animal and plant viruses. Cajal bodies (CBs) form a major sub-nuclear structure whose functions may include the regulation of cellular RNA metabolism. During the lifecycle of human adenovirus 5 (Ad5), CBs are reorganized from their spherical-like structure into smaller clusters termed microfoci. The mechanism of this reorganization and its significance for virus replication has yet to be established. Here we show that the major CB protein, p80-coilin, facilitates the nuclear export of Ad5 transcripts. Depletion of p80-coilin by RNA interference led to lowered levels of viral proteins and infectious virus. p80-coilin was found to form a complex with the viral L4-22K protein in Ad5-infected cells and in some reorganized microfoci. These findings assign a new role for p80-coilin as a potential regulator of infection by a human DNA virus
Encapsulation of vitamin E in yogurt-based beverage emulsions : Influence of bulk pasteurization and chilled storage on physicochemical stability and starter culture viability
Get PDFThis research was funded by the Scottish Government’s Rural and Environment Science and Analytical Services Division (RESAS). Author Contributions Conceptualization, V.R.; methodology, V.R., H.E.H., L.P.P. and S.G.; formal analysis, H.E.H.; data curation, H.E.H. and V.R.; writing—original draft preparation, V.R. and H.E.H.; supervision, V.R. and H.E.H.; funding acquisition, V.R. All authors have read and agreed to the published version of the manuscript.Peer reviewe
Isothermal Kinetics of Catalyzed Air Oxidation of Diesel Soot
Get PDFTo comply with the stringent emission regulations on soot, diesel vehicles manufacturers more and more commonly use diesel particulate filters (DPF). These systems need to be regenerated periodically by burning soot that has been accumulated during the loading of the DPF. Design of the DPF requires rate of soot oxidation. This paper describes the kinetics of catalytic oxidation of diesel soot with air under isothermal conditions. Kinetics data were collected in a specially designed mini-semi-batch reactor. Under the high air flow rate assuming pseudo first order reaction the activation energy of soot oxidation was found to be, Ea = 160 kJ/ mol. ©2010 BCREC UNDIP. All rights reserved(Received: 14th June 2010, Revised: 18th July 2010, Accepted: 9th August 2010)[How to Cite: R. Prasad, V.R. Bella. (2010). Isothermal Kinetics of Catalyzed Air Oxidation of Diesel Soot. Bulletin of Chemical Reaction Engineering and Catalysis, 5(2): 95-101. doi:10.9767/bcrec.5.2.796.95-101][DOI:http://dx.doi.org/10.9767/bcrec.5.2.796.95-101 || or local: http://ejournal.undip.ac.id/index.php/bcrec/article/view/796]Cited by in: ACS 1 |</p
Applications and Preparation Methods of Copper Chromite Catalysts: A Review
Get PDFIn this review article various applications and preparation methods of copper chromite catalysts have been
discussed. While discussing it is concluded that copper chromite is a versatile catalyst which not only catalyses
numerous processes of commercial importance and national program related to defence and space
research but also finds applications in the most concerned problem worldwide i.e. environmental pollution
control. Several other very useful applications of copper chromite catalysts are in production of clean energy,
drugs and agro chemicals, etc. Various preparation methods about 15 have been discussed which depicts
clear idea about the dependence of catalytic activity and selectivity on way of preparation of catalyst.
In view of the globally increasing interest towards copper chromite catalysis, reexamination on the important
applications of such catalysts and their useful preparation methods is thus the need of the time. This
review paper encloses 369 references including a well-conceivable tabulation of the newer state of the art.
Copyright © 2011 by BCREC UNDIP. All rights reserved.
[How to Cite: R. Prasad, and P. Singh. (2011). Applications and Preparation Methods of Copper Chromite
Catalysts: A Review. Bulletin of Chemical Reaction Engineering & Catalysis, 6 (2): 63-113
Augmented reality cueing methodologies for rotorcraft shipboard landings
No full textAugmented Reality Cueing Methodologies For Rotorcraft Shipboard Landings
Robert Walters
159 Pages
The helicopter-ship interface is one of the most challenging flight regimes in which pilots operate. Several factors make this flight regime complicated, such as the relative motion between the aircraft, the ship, and the sea, and also the air wake turbulence and the confined nature of the landing zone. Degraded visuals conditions such as sea spray, adverse weather, and poor lighting conditions compound the other difficulties. The high pilot workload from these factors can lead to a loss of situational awareness which can result in catastrophic aircraft accidents. Currently fielded cueing systems are not up to this challenge.
To reduce pilot workload and improve situational awareness and performance, better pilot cueing is required. This dissertation investigated the extent to which augmented reality cueing utilizing modern rendering techniques reduces pilot workload and improves situational awareness and performance. This was done by supporting a ‘head-up, eyes-out’ ego-centric interface philosophy. The cueing systems sought to incorporate common pilot mission task elements into the design. Changes to both the path preview and trajectory prediction were studied. The visual elements of the cues were displayed as if they were comprised of three dimensional physical objects.
Operational flexibility in high workload environments is key to pilot task accomplishment. The ability to dynamically generate on demand flight trajectories that pilots could manually fly was another goal of this dissertation. The mathematical framework of Bézier curves was utilized for trajectory planning to ensure the paths satisfy the needs of the pilot, the certification authorities, and the specific mission task element.
Four different cueing paradigms were programmed into the Georgia Tech reconfigurable rotorcraft flight simulator. These paradigms were; a 2D Head Up Display (HUD), a Flight Lead Cueing System (FLCS), a Tunnel In the Sky (TIS), and a 3D Flight Path Marker (FPM). The cues were then evaluated using objective measures and pilot workload surveys in a series of Pilot-in-the-Loop (PIL) studies.
A total of twenty pilots took part in the study. Seven pilots participated in phase 1, three in phase 2, and ten in phase 4. Phase 3 included only data flown by the author and LTC Joe Davis due to pandemic related travel restrictions preventing the use of additional external pilots. Most PIL studies have a relatively low number of participants, in the range of two to six. In order to gain statistical significance from a relatively low number of participants the participants are asked to repeat the task several times. For example the pilots in phase 4 each flew a total of 54 approaches. The central limit theorem, states that a distribution will be approximately normally for large sample sizes, where a sample size over 30 is considered large. Consequently even when the data is divided to look at a specific cueing condition or starting location the large sample size criteria is met and we can gain statistical insight.
Bézier curves provide a feasible method to dynamically generate landing trajectories for pilots to fly by hand. The methods are numerically stable and execute fast enough that there is minimal perceptual latency to the pilot. The pilots were able to follow the generated trajectories with sufficient accuracy both laterally and vertically. The paradigm shift of using 3D AR cueing which the pilots mentally process as signals instead of signs or symbols resulted in reduced workload and had performance that was the same or better than traditional cueing methods.Ph.D
A Review on Diesel Soot Emission, its Effect and Control
No full textThe diesel engines are energy efficient, but their particulate (soot) emissions are responsible of severe environmental and health problems. This review provides a survey on published information regarding diesel soot emission, its adverse effects on the human health, environment, vegetations, climate, etc. The legislations to limit diesel emissions and ways to minimize soot emission are also summarized. Soot particles are suspected to the development of cancer; cardiovascular and respiratory health effects; pollution of air, water, and soil; impact agriculture productivity, soiling of buildings; reductions in visibility; and global climate change. The review covers important recent developments on technologies for control of particulate matter (PM); diesel particulate filters (DPFs), summarizing new filter and catalyst materials and DPM measurement. DPF technology is in a state of optimization and cost reduction. New DPF regeneration strategies (active, passive and plasma-assisted regenerations) as well as the new learning on the fundamentals of soot/catalyst interaction are described. Recent developments in diesel oxidation catalysts (DOC) are also summarized showing potential issues with advanced combustion strategies, important interactions on NO2 formation, and new formulations for durability. Finally, systematic compilation of the concerned newer literature on catalytic oxidation of soot in a well conceivable tabular form is given. A total of 156 references are cited. ©2010 BCREC UNDIP. All rights reserved(Received: 2nd June 2010, Revised: 17th June 2010; Accepted: 24th June 2010)[How to Cite: R. Prasad, V.R. Bella. (2010). Review on Diesel Soot Emission, its Effect and Control. Bulletin of Chemical Reaction Engineering and Catalysis, 5(2): 69-86. doi:10.9767/bcrec.5.2.794.69-86][DOI: http://dx.doi.org/10.9767/bcrec.5.2.794.69-86 || or local: http://ejournal.undip.ac.id/index.php/bcrec/article/view/794 ]Cited by in: ACS 1 |</p
Physiological and biochemical changes in imported litchi fruit
Get PDFIt is important to determine the appropriate conditions for maintaining postharvest quality of litchi fruit after arrival from overseas markets. The present study, therefore, aimed to detail the effects of different storage conditions on physiological and biochemical changes in aril and pericarp tissues of imported litchi fruit.
Results from Chapter 4 were the first to fully detail the alterations of individual sugars, organic acids and total phenols in aril and individual anthocyanins in pericarp tissue as well as physiological changes under different storage temperatures in three cropping seasons. Results clearly demonstrated that higher concentrations of sucrose, malic, tartaric and total phenolic contents were maintained at 5°C in aril and higher anthocyanins and total phenolic concentrations in pericarp during 13 days as compared with 8, 10, 13 and 20°C storage. Fruit treated at 5°C also had lower weight loss, brighter red pericarp colour and higher total soluble solids as compared against those fruit stored in other temperatures. A temperature of 5°C was therefore proposed for litchi distribution and storage, and acted as the basis of this study.
Relative humidity (RH) and vapour pressure deficit (VPD) in a storage environment are also important parameters affecting postharvest life. A new system using different glycerol solutions was employed to achieve defined RH levels in the present study. Although effects of RH on postharvest changes in litchi fruit have been described in previous works, the recent study is the first report detailing the effects of different and controlled VPD on litchi postharvest alterations. Low VPD was required to maintain quality of imported litchi during 9 days storage. In addition to reducing both weight loss and respiration rate, storage at 95-100 %RH and 5°C (VPD = 0.000-0.084 kPa) successfully remained high levels of sucrose and malic acid content in aril, and tartaric acid, cyanidin 3-rutinoside and mannose in pericarp tissue. It was therefore recommended that storage conditions for litchi should not only focus on maintenance of the cool chain, but should also consider controlling a VPD of ≤0.068 kPa to attain improved conservation of visual appearance.
Appropriate use of packaging materials can prolong shelf-life of assorted fruit and vegetables including litchi fruit. Imported litchi fruit were wrapped with either micro-perforated polypropylene (PP), PropaFreshTM PFAM (PF), NatureFlexTM NVS, CellophaneTM WS or kept unwrapped prior to storage at 13°C for 9 days. Predictably, packed fruit retained better quality during storage as compared with unwrapped fruit. Each film tested resulted in an altered gas composition in the packages and thus affected postharvest quality. PF significantly decreased hydrolysis of sucrose in aril and retained higher cyanidin 3-rutinoside levels in pericarp. PF film also limited fruit weight loss and maintained sugar and organic acids concentration in both aril and pericarp.
Exogenous application of certain chemicals after harvest has been commercially used to control browning in litchi for many years. However, off-flavours may results and could potentially impact on consumer safety. These possible effects have enhanced demand for non-adulterated fruit on the market. Postharvest changes in pericarp and aril of non-adulterated and commercially-treated fruit as influenced by packaging films under different temperatures were detailed. Although commercially-treated fruit had higher aril organic acids and pericarp anthocyanins, sucrose hydrolysis in aril tissue was accelerated. The use of PF film at 5°C maintained higher sucrose and malic contents in aril tissue of non-adulterated and commercial litchi during 11 days as compared with unwrapped or PP regimes or 13°C storage. Results suggested that PF could replace PP as a new active film for the litchi industry and be a substitute for chemical treatment to maintain quality of litchi fruit
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