bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of Drag and Lift Forces over the Profile of Car with Rearspoiler using CFD
Authors: Velagapudi Naveen Kumar , K. Lalit Narayan , Rao L. N. V. Narasimha , Y. Sri Ram
Published: January 2018

Now a days demand of a high speed car is increasing in which vehicle stability is of major concern. Forces like drag& lift,weight,side forces and thrust acts on a vehicle when moving on road which significantly effect the fuel consumption The drag force is produced by relative motion between air and vehicle and about 60% of total drag is produced at the rear end. Reduction of drag force at the rear end improves the fuel utilization. This work aims to reduce the drag force which improves fuel utilization and protects environment as well. In the stage of work a sedan car with different types of spoilers are used to reduce the aerodynamic drag force. The design of sedan car has been done on CATIA-2010 and the same is used for analysis in ANSYS-(fluent). The analysis is done for finding out drag and lift forces at different velocities, and spoilers. This study proposes an effective numerical model based on the computational fluid dynamics (CFD) approach to obtain the flow structure around a passenger car with a rear spoiler
Latest trend of variation of EDGE detection and object detection with pixel level variation and their comparison algorithms
Authors: Sharma Bhubneshwar , Mahajan Parul
Published: January 2018

The frequent traffic jams at major junctions call for an efficient traffic management system in place. The resulting wastage of time and increase in pollution levels can be eliminated on a city-wide scale by these systems. The image sequences from a camera are analyzed using various edge detection and object counting methods to obtain the most efficient technique. Subsequently, the number of vehicles at the intersection is evaluated and traffic is efficiently managed.
Different types of Sybili attacks and their importance and properties for finding latest mechanism
Authors: Sharma Bhubneshwar , Badhan Ruhika
Published: January 2018

A Mobile Ad hoc Network (MANET) consists of a set of communicating wireless mobile nodes or devices that do not have any form of fixed infrastructure or centralized authority. The security in MANET has become a significant and active topic within the research community. This is because of the high demand in sharing streaming video and audio in various applications .Once MANET is setup it quickly facilitate communications in a hostile environment such as battlefield or emergency situation likes disaster rescue operation. In spite of the several attacks aimed at specific nodes in MANET that have been uncovered, some attacks involving multiple nodes still receive little attention. A reason behind this is because people make use of security mechanisms applicable to wired networks in MANET and overlook the security measures that apply to MANET. Furthermore, it may also have to do with the fact that no survey or taxonomy has been done to clarify the characteristics of different multiple node attacks. This paper addresses the mentioned gap by providing a proper definition and categorization of Sybil attacks in MANET. The whole simulation will take place in MATLAB environment. In the end performance is measured by using the parameters like network load and throughput.
Prevalence of pollution indicators in Palk bay coastal zone, Southern India
Authors: Meera B.
Published: January 2018

In this study, the sea water and sediment samples of four different locations were collected from Palk bay regions during 2014 for pollution indicators study. All the bacterial parameters were higher during the rainy season compared to summer season in all the sampling locations of the Palk bay regions. In the water samples, among the pollution indicator bacterial groups, TC and TS counts were highest 0.67 10.3 [103] ml?1 and 0.8 10.8 [102] ml?1 during monsoon, and the least 0.54 8.5 [103] ml?1 and 0.7 9.0 [102] ml?1 were noticed during summer. In monsoon sediment sample, the higher VC count was observed in Thondi (2100 g?1) followed by Mimisal (1700 g?1), Manamelkudi (960 g?1) and Devipattinam (200 g?1). The pollution index (PI) of each location was calculated and was showed a remarkable microbial contamination was observed in sediment sample than water sample. The order of PI observed were Thondi > Mimisal > Manamelkudi > Devipattinam. The highest PI ratio (15.5) was observed in Devipattinam sediment sample at monsoon season while lowest (2.5) was noticed in Devipattinam water sample at summer season. The results indicated that the coastal environment is highly exposed to human excreta that suggesting to avoid direct contact. Hence, throughout impoundment is needed to protect coastal environments.
Synthesis of Evolvulus alsinoides derived gold nanoparticles for medical applications
Authors: Anbarasu R. , Selvan G. , Baskar S. , Raja V.
Published: January 2018

Plant mediated synthesis of metallic nanoparticles is an increasing commercial demand due to the wide applicability in various areas such as electronics, catalysis, chemistry, energy, cosmetics and medicine. This is greatly due to their special features, which include unusual optical and electronic properties, high stability and biological compatibility, controllable morphology and size dispersion, and easy surface functionalization. In the present investigation, synthesis of gold nanoparticle is done by using leaf extracts of Evolvulus alsinoides. Gold nanoparticles (AuNPs) were characterized by using UV visible absorption spectra. Their morphology, elemental composition and crystalline phase were determined by scanning electron microscopy, energy dispersive X-ray spectroscopy and FT-IR analysis was used to confirm the presence of gold nanoparticles in the extracts. The plant derived gold nanoparticles were also showing more inhibition activity in both bacterial and fungus strains. In bacteria, gram negative strains are highly affected by the test samples than gram positive. In fungal strains, the highest effect was noticed in Trichophyton rubrum while less effect was observed in Candida albicans.
A comparative study of Bupivacaine 0.5% versus Ropivacaine 0.5% for supraclavicular brachial plexus block (subclavian perivascular approach only) in ASA II,III patients
Authors: Pooranan Natarajan , C Dhanasekaran
Published: January 2018

Peripheral nerve blocks have become important in clinical practice because of their role in post-operative pain relief, shortening of patient recovery time & avoiding risks and adverse effects of general anaesthesia. Bupivacaine is a long acting local anaesthetic. Due to its long duration of action and combined with its high quality sensory blockade compared to motor blockade it has been the most commonly used local anaesthetic for peripheral nerve blocks. Ropivacaine is a newer, long acting local anaesthetic whose neuronal blocking potential used in peripheral nerve blockade seems to be equal or superior to bupivacaine. Studies show that it has significantly greater safety margin over bupivacaine. Hence here is an attempt through the study to compare bupivacaine with ropivacaine in supraclavicular brachial plexus block in ASA II&III patients.
Molecular docking studies of deacetylbisacodyl with intestinal sucrase-maltase enzyme
Authors: Merugu Ramchander , Neerudu Uttam Kumar , Dasa Karunakar , Singh Kalpana V.
Published: January 2018

Molecular docking of sucrase-isomaltase with ligand deacetylbisacodyl when subjected to docking analysis using docking server, predicted in-silico result with a free energy of -3.36 Kcal/mol which was agreed well with physiological range for protein-ligand interaction, making bisacodyl probable potent anti-isomaltase molecule. According to docking server Inhibition constant is 5.98Mm. which predicts that the ligand is going to inhibits enzyme and result in a clinically relevant drug interaction with a substrate for the enzyme. Hydrogen bond with bond length 3.45is formed between Pro 64 (A) of target and of ligand, which is again indicative of the docking between target and ligand. Excellent electrostatic interactions of polar, hydrophobic, pi-pi and Van der walls are observed. The proteinligand interaction study showed 6 amino acid residues interaction with the ligand.
Analysis of processing techniques and then quantitative measures which determine most appropriate Donoho's approach for image restoration
Authors: Chowdhary Nitish , Sharma Bhubneshwar
Published: January 2018

The implementation of the regularized inverse filter involves the estimation of the power spectrum of the original image in the spatial domain. Since wavelet transforms have good decor relation property, the wavelet coefficients of the image can be better modeled in a stochastic model, and the power spectrum can be better estimated. Registration algorithms compute transformations to set correspondence between the two images the purpose of this paper is to provide a comprehensive review of the existing literature available on Image registration methods. We believe that it will be a useful document for researchers longing to implement alternative Image registration methods for specific applications.
Bluetooth SIG oversees development of the specification and prediction of program that protects Bluetooth pin
Authors: Dadwal Jyoti , Sharma Bhubneshwar
Published: January 2018

Bluetooth implementsconfidentiality,authenticationandkeyderivation with custom algorithms based on theSAFER+block cipher. Bluetooth key generation is generally based on a Bluetooth PIN, which must be entered into both devices. This procedure might be modified if one of the devices has a fixed PIN (e.g., for headsets or similar devices with a restricted user interface). During pairing, an initialization key or master key is generated, using the E22 algorithm.TheE0 stream cipher is used for encrypting packets, granting confidentiality, and is based on a shared cryptographic secret, namely a previously generated link key or master key. Those keys, used for subsequent encryption of data sent via the air interface, rely on the Bluetooth PIN, which has been entered into one or both devices.
Effect of compost, cow dung and NPK 15-15-15 fertilizer on growth and yield performance of Amaranth (Amaranthus hybridus)
Authors: Sanni Kehinde Oseni
Published: January 2018

Nigerian soils are generally low in fertility and enhanced crop yield is only possible through external use of organic and inorganic fertilizers. The present study was carried out under field condition at Teaching and Research Farms, Lagos State Polytechnic, Ikorodu to evaluate effects of compost, cow dung and NPK 15-15-15 fertilizer amendments on the growth and yield performances of Amaranthus hybridus. The obtained results indicated that all treatments significantly achieved an increment in morphological parameters (numbers of leaves stem girth, leaf area and plant height) and fresh weight yield comparing with the control. The best results in terms of these characters were obtained in the following order Cow dung > compost > NPK 15-15-15 and control. Post soil analysis shows that all the treatments reduced the soil pH from 6.20 to a range between 5.58-5.68 and available phosphorus, magnesium, organic carbon, total nitrogen and CEC increased significantly compared with control plot. Results suggest that the use of cow dung and composts has potential to improve the growth and yield of amaranth and improves the soil physiochemical properties in the study area.
Evaluation of hepatoprotective potential of methanolic extract of the plant dolichos biflorus linn
Authors: B Deepthi , M Ashoka Shenoy , Hegde Karunakar
Published: January 2018

Present study is to evaluate the hepatoprotective potential of methanolic extract of the plant Dolichos biflorus Linn. against paracetamol and alcohol induced hepatotoxicity in rats. Oral administration of plant extract in two doses 200mg/kg and 400mg/kg body weight were subjected for the evaluation of hepatoprotective potential against alcohol (2ml/100g) and PCM (2g/kg) induced liver injury. Silymarin (25mg/kg) was used as a standard drug. The parameters like SGPT, SGO, ALP, TB and endogenous enzymes were estimated to assess the liver functions. In addition histopathological study was also carried out. Both the lower (200mg/kg) and higher dose (400mg/kg) of D.biflorus extract showed dose dependent significant decrease in SGPT, SGOT, ALP and TB levels when compared with toxic control. Both extracts showed decrease in LPO and increase in GSH, SOD and CAT levels. Hepatoprotective effect was also confirmed by histopathological analysis of liver which showed less damage in extract treated rats. The results obtained were comparable with that of the standard. The present study concluded that Dolichos biflorus Linn. plant were found to be effective against hepatotoxicity induced by Alcohol and Paracetamol.
Model for Predicting and Analyzing the %Fe Removed as Deleterious Element from Al-Si alloys During Fe Removal Processing with Mn
Authors: Anene F. A. , Nwankwo N. E.
Published: January 2018

Model equation for predicting and analysing %Fe removed from a eutectic Al-Si alloy during Fe removal processing with Mn under controlled conditions has been derived and validated. The model derived;%Fe removed = +1.30700 + 0.095882* Al-Si + %Mn - 0.068512* Al-Si + %Mn^2 + 9.77000E-003* Al-Si+%Mn^3 ,is found to predict the %Fe removed from Al-Si alloy as a cubic function of Mn content. With a standard deviation of 0.010. Analysed results obtained show that %Fe removal equation with Mn addition has been validly derived. The model " R-Squared" of 0.9814 is found to be in agreement with the "Adj R-Squared" of 0.9628; the difference being less than 0.2. The derived model equation gives a reasonable forecast of %Fe removed very close to the values obtained from the experiments. The close proximity of both model and experimental result values is attributed to the low standard error of the model coefficients. The processing parameters are process temperature, alloy contents and holding time.
Comparison of 0.2% Bupivacaine with 0.2% Ropivacaine in Femoral Nerve Block for Preoperative Positioning and Postoperative Analgesia in Femur Fractures
Authors: P Natarajan , K. Srinivasan S. , C Dhanasekaran , K. Sekaran N.
Published: January 2018

Introduction: Femur fractures are very painful. The peripheral nerve block provides good analgesia in these patients before performing regional anesthesia. This study aims to compare 2 local anesthestics in femoral nerve block for analgesia in preoperative positioning and postoperative analgesia of patientsMethods: Prospective, randomized study was conducted on 60 patients (18-60 years) of ASA I&II scheduled for femur surgery under combined spinal epidural. anaesthesia In group B (n=30), femoral nerve block(FNB) was performed with 0.2% bupivacaine (30ml) and in group R(n=30), 0.2% ropivacaine (30 ml) was used. Various parameters like numeric rating pain scale, time to spinal anaesthesia, sensory and motor block onset times and durations, time to first analgesic use, intraoperative & postoperative visual analog scale (VAS) data, post- operative epidural top ups, vitals and side effects were recorded for each patient.Results: Pain assessed on visual analogue scale (VAS) during positioning was significantly less in FNB group using 0.2%bupivacaine at 5 minutes. Time to perform spinal block was significantly shorter in FNB group using 0.2% bupivacaine (8.30 min) versus ropivacaine group (17.30 min). But postoperative analgesic requirements were more in ropivacaine group and duration of analgesia was prolonged in bupivacaine group.Conclusion: With bupivacaine time to perform spinal anesthesia was reduced and postoperative analgesia was better with bupivacaine group.
Bioreduction of silver nanoparticles characterizations and their antimicrobial activity
Authors: Gowthami A. , Kanna A. Vinoth , Uma sankari T. , Moin Sarmad
Published: January 2018

In this investigation we report the bioreduction of silver nitrate to silver nanoparticles using the leaves aqueous extract of Alangium lamarckii. The silver nanoparticles were characterized by UVvis spectrophotometer, scanning electron microscope (SEM), DLS-Size and zeta potential analysis showed that the synthesized silver nanoparticles are varied from 60 - 70 nm and have the spherical shape. Further the prospect of protein as a stabilizing material in silver nanoparticles is shown by FTIR analysis and the XRD examination confirms monocrystalline phase of silver with FCC crystal structure. The antimicrobial activity of Ag nanoparticles was investigated against some pathogens. In these assessments, silver nanoparticles (AgNP) can stop microbial growth and even kill microbes, from now confirmed their antimicrobial importance.
Structure and function of aconitase enzyme in TCA by estimating optical rotation of glucose and determining the relationship between cell density and absorbance
Authors: Raza Shahid , Ameen Ayesha
Published: January 2018

Enzyme aconitase have a great value in TCA path, this enzyme use to convert pyruvate and acetyl co A in to citrate and cis aconitase ( a six carbon molecule). This study was designed to find the tertiary structure of aconitase with and without ligand by using RSBC. The TCA cycle start with the pyruvate that is end product of glycolysis cycle. This study also focused on the optical rotation of glucose molecule before its breakdown start naturally through glycolysis and absorbance / transmittance of viable cells would be estimated.
Effect of IBA concentration on the production of coratina olive plant
Authors: Ameen Ayesha , Ahmad Jalil , Raza Shahid
Published: January 2018

The effect of different concentrations of indole butyric acid (IBA) at 4g/L and 0.12/31.2 ml hardwood and semi hardwood cuttings of coratina olive was observed. Cuttings were taken in the month of February from coratina plant and dipped for 10 seconds in the required IBA solutions. The highest survival percentage, shoot formation, number of roots formation was maximum in 4g/L treated hardwood cuttings. The maximum number of branches were observed in hardwood cuttings as compared to softwood cuttings. It was concluded that either type of olive cutting treated with IBA solution 4g/L showed best results to propagate coratina olive.
In silico analysis of fluoride transport proteins from prokaryotic and eukaryotic organisms
Authors: Merugu Ramchander , Radarapu Sireesha , Dasari Sandhya Rani , Mandala Jyothi
Published: January 2018

In silico analysis of Fluoride transporter proteins obtained from database are presented in this study. The composition of alanine and glycine was high while low concentrations of aspartic acid, cysteine and glutamine were seen when compared to other aminoacids. Molecular weight of fungal transporters was the highest while the bacterial showed relatively less molecular weights. The instability index of all the proteins was less than 40 showing that all of them are stable except that of Neurospora and Bifidobacterium. Aliphatic index was found to be within a range of 65 to 100.
SOPs of MSW Composting process by Lahore compost Private Limited
Authors: Raza Shahid , Ahmad Jalil
Published: January 2018

LCL is operating an aerobic composting plant at Lahore that has been purchased from and installed by the Menart Composting Company, Belgium. Since municipal solid waste (MSW) in Lahore is heterogeneous a screening drum (MTR 1850) installed to screen the waste before composting with additional possibility for hand-sorting of recyclables in a sorting belt. This Standard Operation Procedure (SOP) has been prepared for and adopted by the composting plant of the Lahore Compost Ltd (LCL). The SOP intends to ensure that LCL adopts the identified best practices in the plant, operates it through standard recommended procedures; and takes necessary corrective actions when required
A review on theoretical models of suicide
Authors: Karthick S , Barwa Sangita
Published: January 2018

Suicide is a major public health issue which is highly complex and multifaceted. Subsequently, after the pioneering work of Durkheim and Freud, researchers and scholars have attempted to explain the biological, social, and psychological nature of suicide. The present work presents an overview of different theoretical models underlying the development of suicidal behavior.Hence the theory components will be a better understanding of the causal mechanisms of suicide and it will lead to improving the intervention strategies for suicidal behaviors.
Telomere repeats induce domains of H3K27 methylation in Neurospora
Authors: Jamieson Kirsty , McNaught Kevin J , Ormsby Tereza , Leggett Neena A , Honda Shinji , Selker Eric U
Published: January 2018

Development in higher organisms requires selective gene silencing, directed in part by di-/trimethylation of lysine 27 on histone H3 (H3K27me2/3). Knowledge of the cues that control formation of such repressive Polycomb domains is extremely limited. We exploited natural and engineered chromosomal rearrangements in the fungus Neurospora crassa to elucidate the control of H3K27me2/3. Analyses of H3K27me2/3 in strains bearing chromosomal rearrangements revealed both position-dependent and position-independent facultative heterochromatin. We found that proximity to chromosome ends is necessary to maintain, and sufficient to induce, transcriptionally repressive, subtelomeric H3K27me2/3. We ascertained that such telomere-proximal facultative heterochromatin requires native telomere repeats and found that a short array of ectopic telomere repeats, (TTAGGG)17, can induce a large domain (~225 kb) of H3K27me2/3. This provides an example of a cis-acting sequence that directs H3K27 methylation. Our findings provide new insight into the relationship between genome organization and control of heterochromatin formation.
Translating genomics into practice for real-time surveillance and response to carbapenemase-producing Enterobacteriaceae: evidence from a complex multi-institutional KPC outbreak
Authors: Kwong Jason C. , Lane Courtney R. , Romanes Finn , Gonçalves da Silva Anders , Easton Marion , Cronin Katie , Waters Mary Jo , Tomita Takehiro , Stevens Kerrie , Schultz Mark B. , Baines Sarah L. , Sherry Norelle L. , Carter Glen P. , Mu Andre , Sait Michelle , Ballard Susan A. , Seemann Torsten , Stinear Timothy P. , Howden Benjamin P.
Published: January 2018

Background

Until recently,Klebsiella pneumoniaecarbapenemase (KPC)-producing Enterobacteriaceae were rarely identified in Australia. Following an increase in the number of incident cases across the state of Victoria, we undertook a real-time combined genomic and epidemiological investigation. The scope of this study included identifying risk factors and routes of transmission, and investigating the utility of genomics to enhance traditional field epidemiology for informing management of established widespread outbreaks.

Methods

All KPC-producing Enterobacteriaceae isolates referred to the state reference laboratory from 2012 onwards were included. Whole-genome sequencing was performed in parallel with a detailed descriptive epidemiological investigation of each case, using Illumina sequencing on each isolate. This was complemented with PacBio long-read sequencing on selected isolates to establish high-quality reference sequences and interrogate characteristics of KPC-encoding plasmids.

Results

Initial investigations indicated that the outbreak was widespread, with 86 KPC-producing Enterobacteriaceae isolates (K. pneumoniae92%) identified from 35 different locations across metropolitan and rural Victoria between 2012 and 2015. Initial combined analyses of the epidemiological and genomic data resolved the outbreak into distinct nosocomial transmission networks, and identified healthcare facilities at the epicentre of KPC transmission. New cases were assigned to transmission networks in real-time, allowing focussed infection control efforts. PacBio sequencing confirmed a secondary transmission network arising from inter-species plasmid transmission. Insights from Bayesian transmission inference and analyses of within-host diversity informed the development of state-wide public health and infection control guidelines, including interventions such as an intensive approach to screening contacts following new case detection to minimise unrecognised colonisation.

Conclusion

A real-time combined epidemiological and genomic investigation proved critical to identifying and defining multiple transmission networks of KPC Enterobacteriaceae, while data from either investigation alone were inconclusive. The investigation was fundamental to informing infection control measures in real-time and the development of state-wide public health guidelines on carbapenemase-producing Enterobacteriaceae surveillance and management.
Artifacts in Century‐Length Atmospheric and Coupled Reanalyses Over Antarctica Due To Historical Data Availability
Authors: Schneider David P. , Fogt Ryan L.
Published: January 2018

Enabled by advances in data assimilation and the digitization of historical observations, atmospheric reanalysis products that span the entire twentieth century provide valuable gridded data over the sparsely observed high‐latitude Southern Hemisphere. Here austral summer and winter surface pressure trends in three reanalyses are compared to trends in a statistically based pressure reconstruction, trends in atmospheric models without data assimilation, and estimates of uncertainty from the reanalyses. In austral summer during the early twentieth century, the reanalyses underestimate the depth of the circumpolar trough, leading to erroneously high pressure values over the region. Around 1950, a rapid increase in the number of assimilated pressure observations leads to a dramatic reduction in the reanalyses standard error and a spurious drop in the surface pressure. A more likely history of the surface pressure over this region is provided by the reconstruction, which is consistent with the model simulations without data assimilation.
Precipitation, Convective Clouds, and Their Connections With Tropical Cyclone Intensity and Intensity Change
Authors: Ruan Zhenxin , Wu Qiaoyan
Published: January 2018

In this paper, satellite‐based precipitation, clouds with infrared (IR) brightness temperature (BT), and tropical cyclone (TC) data from 2000 to 2015 are used to explore the relationship between precipitation, convective cloud, and TC intensity change in the Western North Pacific Ocean. An IR BT of 208 K was chosen as a threshold for deep convection based on different diurnal cycles of IR BT. More precipitation and colder clouds with 208 K < IR BT < 240 K are found as storms intensify, while TC 24 h future intensity change is closely connected with very deep convective clouds with IR BT < 208 K. Intensifying TCs follow the occurrence of colder clouds with IR BT < 208 K with greater areal extents. As an indicator of very deep convective clouds, IR BT < 208 K is suggested to be a good predictor of TC intensity change. Based upon the 16 year analysis in the western North Pacific, TCs under the conditions that the mean temperature of very deep convective clouds is less than 201 K, and the coverage of this type of clouds is more than 27.4% within a radius of 300 km of the TC center, will more likely undergo rapid intensification after 24 h.
Three‐Step Buildup of the 17 March 2015 Storm Ring Current: Implication for the Cause of the Unexpected Storm Intensification
Authors: Keika Kunihiro , Seki Kanako , Nosé Masahito , Miyoshi Yoshizumi , Lanzerotti Louis J. , Mitchell Donald G. , Gkioulidou Matina , Manweiler Jerry W.
Published: January 2018

We examine the spatiotemporal variations of the energy density and the energy spectral evolution of energetic ions in the inner magnetosphere during the main phase of the 17 March 2015 storm, using data from the RBSPICE and EMFISIS instruments onboard Van Allen Probes. The storm developed in response to two southward IMF intervals separated by about 3 h. In contrast to two steps seen in the Dst/SYM‐H index, the ring current ion population evolved in three steps: the first subphase was apparently caused by the earlier southward IMF, and the subsequent subphases occurred during the later southward IMF period. Ion energy ranges that contribute to the ring current differed between the three subphases. We suggest that the spectral evolution resulted from the penetration of different plasma sheet populations. The ring current buildup during the first subphase was caused by the penetration of a relatively low‐energy population that had existed in the plasma sheet during a prolonged prestorm northward IMF interval. The deeper penetration of the lower‐energy population was responsible for the second subphase. The third subphase, where the storm was unexpectedly intensified to a Dst/SYM‐H level of <−200 nT, was caused by the penetration of a hot, dense plasma sheet population. We attribute the hot, dense population to the entry of hot, dense solar wind into the plasma sheet and/or ion heating/acceleration in the near‐Earth plasma sheet associated with magnetotail activity such as reconnection and dipolarization.
Origins of the Thermosphere‐Ionosphere Semiannual Oscillation: Reformulating the “Thermospheric Spoon” Mechanism
Authors: Jones M. , Emmert J. T. , Drob D. P. , Picone J. M. , Meier R. R.
Published: January 2018

We demonstrate how Earth's obliquity generates the global thermosphere‐ionosphere (T‐I) semiannual oscillation (SAO) in mass density and electron density primarily through seasonally varying large‐scale advection of neutral thermospheric constituents, sometimes referred to as the “thermospheric spoon” mechanism (TSM). The National Center for Atmospheric Research thermosphere‐ionosphere‐mesosphere‐electrodynamics general circulation model (TIME‐GCM) is used to isolate the TSM forcing of this prominent intraannual variation (IAV) and to elucidate the contributions of other processes to the T‐I SAO. An ∼30% SAO in globally averaged mass density (relative to its global annual average) at 400 km is reproduced in the TIME‐GCM in the absence of seasonally varying eddy diffusion, tropospheric tidal forcing, and gravity wave breaking. Artificially, decreasing the tilt of Earth's rotation axis with respect to the ecliptic plane to 11.75° reduces seasonal variations in insolation and weakens interhemispheric pressure differences at the solstices, thereby damping the global‐scale, interhemispheric transport of atomic oxygen (O) and molecular nitrogen in the thermosphere and reducing the simulated global mass density SAO amplitude to ∼10%. Simulated T‐I IAVs in mass density and electron density have equinoctial maxima at all latitudes near the F2 region peak; this phasing and its latitude dependence agree well with empirically inferred climatologies. When tropospheric tides and gravity waves are included, simulated IAV amplitudes and their latitudinal dependence also agree well with empirically inferred climatologies. Simulated meridional and vertical transport of O due to the TSM couples to the upper mesospheric circulation, which also contributes to the T‐I SAO through O chemistry.
Survey of the Favorable Conditions for Magnetosonic Wave Excitation
Authors: Kim Kyung‐Chan , Shprits Yuri
Published: January 2018

The ratio of the proton ring velocity (VR) to the local Alfven speed (VA), in addition to proton ring distributions, plays a key factor in the excitation of magnetosonic waves at frequencies between the proton cyclotron frequency fcp and the lower hybrid resonance frequency fLHR in the Earth's magnetosphere. Here we investigate whether there is a statistically significant relationship between occurrences of proton rings and magnetosonic waves both outside and inside the plasmapause using particle and wave data from Van Allen Probe‐A during the time period of October 2012 to December 2015. We also perform a statistical survey of the ratio of the ring energy (ER, corresponding to VR) to the Alfven energy (EA, corresponding to VA) to determine the favorable conditions under which magnetosonic waves in each of two frequency bands (fcp < f ≤ 0.5 fLHR and 0.5 fLHR < f < fLHR) can be excited. The results show that the magnetosonic waves in both frequency bands occur around the postnoon (12–18 magnetic local time, MLT) sector outside the plasmapause when ER is comparable to or lower than EA, and those in lower‐frequency bands (fcp < f ≤ 0.5 fLHR) occur around the postnoon sector inside the plasmapause when ER/EA > ~9. However, there is one discrepancy between occurrences of proton rings and magnetosonic waves in low‐frequency bands around the prenoon sector (6–12 MLT) outside the plasmapause, which suggests either that the waves may have propagated during active time from the postnoon sector after being excited during quiet time, or they may have locally excited in the prenoon sector during active time.
Ultrahigh‐Pressure Phase Transitions in FeS2 and FeO2: Implications for Super‐Earths' Deep Interior
Authors: Huang Shengxuan , Wu Xiang , Qin Shan
Published: January 2018

Iron oxides play an important role in planetary evolution, but little information about the structural properties of AX2‐type iron oxides under extreme conditions limits our understanding of the so‐called “super‐Earth” planets. Here an investigation into the high‐pressure behavior of FeO2 as well as its sulfide counterpart FeS2, has been conducted by first‐principle calculations based on density functional theory. Both FeO2 and FeS2 are predicted to undergo a
‐
‐I4/mmm transition sequence at extreme pressure. Differences in high‐pressure behaviors between FeO2 and FeS2 have been discussed in detail, such as effective coordination number and elasticity. This study not only resolves the controversy about the structural stability of FeS2 under high pressure but also suggests the tenfold coordinated I4/mmm‐type FeO2 may contribute to local chemical heterogeneity by accumulation in the deep interior of a large super‐Earth or water‐rich planet, whose pressure at the core‐mantle boundary can reach 2 TPa.
Impact of East Asian Summer Monsoon on Surface Ozone Pattern in China
Authors: Li Shu , Wang Tijian , Huang Xing , Pu Xi , Li Mengmeng , Chen Pulong , Yang Xiu‐Qun , Wang Minghuai
Published: January 2018

Tropospheric ozone plays a key role in regional and global atmospheric and climate systems. In East Asia, ozone can be affected both in concentration level and spatial pattern by typical monsoon climate. This paper uses three different indices to identify the strength of East Asian summer monsoon (EASM) and explores the possible impact of EASM intensity on the ozone pattern through synthetic and process analysis. The difference in ozone between three strong and three weak monsoon years was analyzed using the simulations from regional climate model RegCM4‐Chem. It was found that EASM intensity can significantly influence the spatial distribution of ozone in the lower troposphere. When EASM is strong, ozone in the eastern part of China (28°N ‐ 42° N) is reduced, but the inverse is detected in the north and south. The surface ozone difference ranges from −7 to 7 ppbv during the 3 months (June to August) of the EASM, with the most obvious difference in August. Difference of the 3 months' average ozone ranges from −3.5 to 4 ppbv. Process analysis shows that the uppermost factor controlling ozone level during summer monsoon seasons is the chemistry process. Interannual variability of EASM can impact the spatial distribution of ozone through wind in the lower troposphere, cloud cover, and downward shortwave radiation, which affect the transport and chemical formation of ozone. The phenomenon should be addressed when considering the interaction between ozone and the climate in East Asia region.
Assessing Parameter Importance of the Weather Research and Forecasting Model Based On Global Sensitivity Analysis Methods
Authors: Ji Dong , Dong Wenjie , Hong Tao , Dai Tanlong , Zheng Zhiyuan , Yang Shili , Zhu Xian
Published: January 2018

The effectiveness and efficiency of two state‐of‐the‐art global sensitivity analysis (SA) methods, the Morris and surrogate‐based Sobol' methods, are evaluated using the Weather Research and Forecasting (WRF) model, version 3.6.1. The sensitivities of precipitation and other related meteorological variables to 11 selected parameters in the new Kain‐Fritsch Scheme, WRF Single‐Moment 6‐class Scheme, and Yonsei University Scheme are then investigated. The results demonstrate that (1) the Morris method is effective and efficient for screening important parameters qualitatively, and with recommended settings of levels p = 8 and replication times r = 10 only 10 × (D + 1) WRF runs are required, where D is the dimension of parameter space; (2) Gaussian process regression (GP) is the best method for constructing surrogates, and the GP‐based Sobol' method can provide reliable quantitative results for sensitivity analysis when the number of WRF runs exceeds 200; and (3) the sensitivity index μ∗ in the Morris method is closely related to the Sobol' index ST, and even for qualitative sensitivity analysis, the GP‐based Sobol' method is more efficient compared to the Morris method. The SA results show that larger values of the downdraft‐related parameter x1, entrainment‐related parameter x2, and downdraft starting height x3 significantly decrease rainfall, while the maximum allowed value for the cloud ice diameter x6 has a moderate decreasing effect on precipitation. This work is useful for further tuning of the WRF to improve the agreement between the climate model and observations.
Retracted: Time‐Dependent Cryospheric Longwave Surface Emissivity Feedback in the Community Earth System Model
Authors: Kuo Chaincy , Feldman Daniel R. , Huang Xianglei , Flanner Mark , Yang Ping , Chen Xiuhong
Published: January 2018

Frozen and unfrozen surfaces exhibit different longwave surface emissivities with different spectral characteristics, and outgoing longwave radiation and cooling rates are reduced for unfrozen scenes relative to frozen ones. Here physically realistic modeling of spectrally resolved surface emissivity throughout the coupled model components of the Community Earth System Model (CESM) is advanced, and implications for model high‐latitude biases and feedbacks are evaluated. It is shown that despite a surface emissivity feedback amplitude that is, at most, a few percent of the surface albedo feedback amplitude, the inclusion of realistic, harmonized longwave, spectrally resolved emissivity information in CESM1.2.2 reduces wintertime Arctic surface temperature biases from −7.2 ± 0.9 K to −1.1 ± 1.2 K, relative to observations. The bias reduction is most pronounced in the Arctic Ocean, a region for which Coupled Model Intercomparison Project version 5 (CMIP5) models exhibit the largest mean wintertime cold bias, suggesting that persistent polar temperature biases can be lessened by including this physically based process across model components. The ice emissivity feedback of CESM1.2.2 is evaluated under a warming scenario with a kernel‐based approach, and it is found that emissivity radiative kernels exhibit water vapor and cloud cover dependence, thereby varying spatially and decreasing in magnitude over the course of the scenario from secular changes in atmospheric thermodynamics and cloud patterns. Accounting for the temporally varying radiative responses can yield diagnosed feedbacks that differ in sign from those obtained from conventional climatological feedback analysis methods.
A Case Study of Low‐Level Jets in Yerevan Simulated by the WRF Model
Authors: Gevorgyan Artur
Published: January 2018

Capabilities of high‐resolution (3 km) Weather Research and Forecasting (WRF) simulations to reproduce topographically induced mountain‐valley winds and low‐level jets (LLJs) in Yerevan have been evaluated using high‐frequency observational and modeled data. High sensitivities of simulations of near‐surface winds and LLJ characteristics observed on 4 July 2015 to both boundary layer and initial and lateral boundary conditions setup have been demonstrated. Among the nine tested planetary boundary layer (PBL) parameterization schemes the MYJ, QNSE, and TEMF PBL schemes showed greater skill in simulation of near‐surface valley winds over Yerevan, while the other PBL schemes tend to significantly underestimate the strength of valley winds, with the BouLac PBL scheme being the worst performer. Most of PBL schemes simulate well‐defined LLJs in Yerevan associated with evening valley winds. The simulated jet cores are mostly located between 150 and 250 m above ground with magnitudes varying from 12 to 21 m s−1. However, the intensity of the observed nocturnal LLJ in Yerevan (located at 110 m above ground) is strongly underestimated by most of the WRF runs while the Shin and Hong and YSU PBL schemes simulate nocturnal LLJs higher than the observed LLJ. The WRF runs initiated with newly released European Centre for Medium‐Range Weather Forecasts ERA‐5 data set showed improved simulation of near‐surface winds and nighttime potential temperatures in Yerevan relative to those forced by the Global Forecast System fields.
Synoptic Formation of Double Tropopauses
Authors: Liu Chengji , Barnes Elizabeth
Published: January 2018

Double tropopauses are ubiquitous in the midlatitude winter hemisphere and represent the vertical stacking of two stable tropopause layers separated by a less stable layer. By analyzing COSMIC GPS data, reanalysis, and eddy life cycle simulations, we demonstrate that they often occur during Rossby wave breaking and act to increase the stratosphere‐to‐troposphere exchange of mass. We further investigate the adiabatic formation of double tropopauses and propose two mechanisms by which they can occur. The first mechanism operates at the tropopause break in the subtropics where the higher tropical tropopause sits on one side of the break and the lower extratropical tropopause sits on the other. The double tropopauses are then formed by differential meridional advection of the higher and lower tropopauses on the two sides of the tropopause break. We show that anticyclonic wave breaking can form double tropopauses mainly by providing stronger poleward advection of the higher tropopause in its poleward lobe. Cyclonic wave breaking mainly forms double tropopauses by providing stronger equatorward advection of the lower tropopause in its equatorward lobe. We demonstrate in the COSMIC GPS data and reanalysis that about half of the double tropopauses in the Northern Hemisphere winter can be directly attributed to such differential advection. For the second mechanism, adiabatic destabilization of the air above the tropopause contributes to the formation of a double tropopause. In this case, a tropopause inversion layer is necessary for this destabilization to result in a double tropopause.
Contrasting Impacts of the South Pacific Split Jet and the Southern Annular Mode Modulation on Southern Ocean Circulation and Biogeochemistry
Authors: Chiang John C. H. , Tokos K. S. , Lee S.‐Y. , Matsumoto K.
Published: January 2018

A recent hypothesis postulated that paleoclimate changes to the Southern Hemisphere westerlies were characterized by the modulation of the wintertime South Pacific Split Jet. We explore this hypothesis further through simulating changes to the ocean circulation from Split Jet modulation, contrasting them against changes associated with the wintertime Southern Annular Mode (SAM). Three responses distinguish the Split Jet from the SAM impact on ocean circulation. (i) A weaker Split Jet strengthens the South Pacific subtropical gyre, leading to stronger western boundary currents and warming of the sea surface temperatures (SSTs) surrounding New Zealand. (ii) A positive SAM leads to an increase in the Antarctic Circumpolar Current and specifically Drake Passage throughflow. And (iii) a weaker Split Jet leads to increased formation of Subantartic Mode Water, whereas a positive SAM leads to increased Antarctic Intermediate Water. Both a weaker Split Jet and positive SAM lead to increased Southern Ocean meridional overturning circulation, though it is more pronounced for the latter. However, enhanced ventilation of deep water in both cases increases atmospheric pCO2 by only 1–3 ppm, because the associated cooling and efficient nutrient utilization in the model effectively negates the venting of deep ocean carbon. Both a weaker Split Jet and positive SAM enhance oxygenation of the deep ocean and intermediate waters but diminish oxygenation of the eastern equatorial Pacific. Our results provide guidance to distinguish SAM‐like changes from Split Jet‐like changes in paleoceanographic records, and we discuss the case of early deglacial transition to Heinrich 1.
No Change in Southern Ocean Circulation in the Indian Ocean From the Eocene Through Late Oligocene
Authors: Wright Nicky M. , Scher Howie D. , Seton Maria , Huck Claire E. , Duggan Brian D.
Published: January 2018

Deciphering the evolution of Southern Ocean circulation during the Eocene and Oligocene has important implications for understanding the development of the Antarctic Circumpolar Current and transition to Earth's “icehouse” climate. To better understand ocean circulation patterns in the Indian Ocean sector of the Southern Ocean, we generated a new fossil fish tooth neodymium isotope record (εNd) from the upper Eocene to upper Oligocene sections (36–23 Ma) of Ocean Drilling Program Sites 744 and 748 (Kerguelen Plateau, Indian Ocean). Reconstructed seawater εNd values from fossil fish teeth are used to trace changes in water masses across ocean basins. The records from Site 748 and Site 744 reveal a gradual shift from εNd values around −6.5 to −7.5 in the late Eocene to εNd values between −7.5 and −8.3 by the late Oligocene, consistent with a Circumpolar Deep Water (CDW) influence at the Kerguelen Plateau throughout the Oligocene. We interpret the shift to less radiogenic values to reflect the increased export of Northern Component Water to the Southern Ocean, likely into the proto‐CDW. However, the records show no major change in water mass composition around the Kerguelen Plateau that would accompany an increase in Pacific throughflow related to the opening of Drake Passage and imply that Pacific throughflow via the Drake Passage occurred by the late Eocene. High‐frequency variability in ɛNd values at Site 744 is interpreted as an imprint of Oligocene glacial activity, with a particularly pronounced excursion at 32.6 Ma roughly coinciding with other glacial weathering indicators around Antarctica.
Measures of Model Performance Based On the Log Accuracy Ratio
Authors: Morley S. K. , Brito T. V. , Welling D. T.
Published: January 2018

Quantitative assessment of modeling and forecasting of continuous quantities uses a variety of approaches. We review existing literature describing metrics for forecast accuracy and bias, concentrating on those based on relative errors and percentage errors. Of these accuracy metrics, the mean absolute percentage error (MAPE) is one of the most common across many fields and has been widely applied in recent space science literature and we highlight the benefits and drawbacks of MAPE and proposed alternatives. We then introduce the log accuracy ratio and derive from it two metrics: the median symmetric accuracy and the symmetric signed percentage bias. Robust methods for estimating the spread of a multiplicative linear model using the log accuracy ratio are also presented. The developed metrics are shown to be easy to interpret, robust, and to mitigate the key drawbacks of their more widely used counterparts based on relative errors and percentage errors. Their use is illustrated with radiation belt electron flux modeling examples.
Recent Advances on 3D Printing Technique for Thermal‐Related Applications
Authors: Nguyen Nam , Park Jin Gyu , Zhang Songlin , Liang Richard
Published: January 2018

Advances in ink formulation and printing techniques make producing material systems with new and versatile characteristics and functionalities possible. Additive manufacturing or 3D printing enables fabricating complex structures at a faster production rate using different types of materials for various applications. Recently, 3D printing methods are being studied for thermal‐related applications. In this paper, the authors review recent progress of materials and printing techniques for thermal application devices using composite materials.