bluuebunny/crossref_metadata_2025 huggingface dataset:
Operation and Performance of the ATLAS Tile Calorimeter
Authors: Pedro Rute
Published: December 2020

The Tile Calorimeter (TileCal), the central hadronic calorimeter of the ATLAS detector, is a key system to measure jets and the missing transverse energy. It uses plastic scintillators interleaved by steel plates, with optical fibre readout and photomultipliers to detect the scintillating light produced by the passage of particles. The TileCal energy scale was obtained in tests with beam tests and, during operation, dedicated calibration systems monitor each step of the readout chain to address response fluctuations. The detector performance in Run 2 was studied with isolated particles and data quality was assessed with the large sample of proton-proton collisions. In this proceeding, the methods and results of the TileCal calibration, operation and performance in Run 2 are presented.
LVD status report: underground muon physics
Authors: Agafonova N
Published: December 2020

The scintillation LVD detector is used to study cosmic ray muons with mean energy of 280 GeV at an average depth of 3.6 km w.e. The experiment has been going on since 1992 at the Gran Sasso underground laboratory, Italy. During 28 years of work, the characteristics of the muon flux, its dependence on depth and seasonal variations and, the charge muon ratio, the multiplicity curve of muon groups and the decoherent curve have been obtained.
Performance for proton anisotropic flow measurement of the CBM experiment at FAIR
Authors: Golosov O , Klochkov V , Kashirin E , Selyuzhenkov I
Published: December 2020

The Compressed Baryonic Matter experiment (CBM) performance for proton anisotropic flow measurements is studied with Monte-Carlo simulations using collisions of gold ions at lab momentum of 12A GeV/c employing DCM-QGSM-SMM heavy-ion event generator. Realistic procedures are used for centrality estimation with the number of registered tracks and particle identification with information from Time-Of-Flight detector. Variation of directed flow estimates depending on various combinations of PSD modules is used to evaluate possible systematic biases due to collision symmetry plane estimation.
Topological studies of light-flavor hadron production in pp, p–Pb, and Pb–Pb collisions with ALICE at the LHC
Authors: Tripathy Sushanta
Published: December 2020

Recent results for high multiplicity pp and p-Pb collisions have revealed that they exhibit heavy-ion-like behaviors. To understand the origin(s) of these unexpected phenomena, event shape observables such as transverse spherocity

(

S
0

p
T

=
1

)

and the relative transverse activity classifier (R
T) can be exploited as a powerful tools to disentangle soft (non-perturbative) and hard (perturbative) particle production. The production of light-flavor hadrons is shown for various

S
0

p
T

=
1

classes in pp collisions at

s

=
13

TeV

measured with the ALICE detector at the LHC. The evolution of average transverse momentum

(

〈

p
T

〉

)

with charged-particle multiplicity, and identified particle ratios as a function of pT
for different

S
0

p
T

=
1

are also presented. In addition, the system size dependence of charged-particle production in pp, p–Pb, and Pb–Pb collisions at

s

N
N

=
5.02

TeV

is presented. The evolution of 〈pT
〉 in different topological regions as a function of RT
are presented. Finally, using the same approach, we present a search for jet quenching behavior in small collision systems.
Studies of excited states of beauty hadrons at CMS
Authors: Ivanov Kirill
Published: December 2020

Studies of excited states of beauty mesons and baryons, performed at the CMS Experiment, are presented. The first observation of

B
c
+

(
2
S
)

and

B
c

*
+

(
2
S
)

states in the

B
c
+

π
+

π
−

invariant mass spectrum is reported as well as the study of excited Λb(5912)0, Λb(5920)0, Λb(6146)0 and Λb(6152)0 baryons decaying to

Λ
b
0

π
+

π
−

. The analyses use Run-2 data, collected in pp collisions at

s

=
13

TeV

.
Physics prospects for ATLAS at the HL-LHC
Authors: Nielsen J
Published: December 2020

The ATLAS experiment at CERN will undergo a series of detector upgrades over the next few years to prepare for the the High-Luminosity Large Hadron Collider (HL-LHC) project. The upgrades are designed to maintain or improve detector performance, even with the instantaneous luminosity needed to deliver a total of 3000 fb−1 of proton-proton collision data at

s

=
14

TeV

to ATLAS. This contribution provides details of the broad and deep program of measurements and searches planned by ATLAS for the HL-LHC. The higher centre-of-mass energy and increased integrated luminosity will allow ATLAS not only to improve the precision of Higgs boson, electroweak boson, and top quark measurements, but also to extend the sensitivity of searches for beyond-the-Standard-Model processes with small cross sections. Many of the projections use detailed detector simulations to model the performance of the proposed ATLAS detector upgrades.
DANSS experiment: current status and future plans
Authors: Svirida D
Published: December 2020

DANSS is a solid scintillator antineutrino detector located right below a 3 GWth reactor of the Kalininskaya NPP. One cubic meter of the sensitive volume with fine segmentation makes it possible to achieve an unprecedented counting rate of about 5000 IBD events per day, keeping the level of cosmic background below 2%. New physics with sterile neutrino is searched for by performing spectral measurements at varying distance from the reactor core. Contributions to the applied antineutrino physics include reactor power measurements and fuel analysis. Commissioned in 2016, DANSS accumulated about 4 million antineutrino events by this fall. Advances in the data analysis will be reported, including improvements in the energy calibration and the optimization of the selection cuts. DANSS upgrade plans include new scintillator strips with higher light collection efficiency and better homogeneity. Expected improvement in the energy resolution will significantly increase the experiment sensitivity to the light sterile neutrino.
Evaluation of the productivity for new design single slope solar still at different saltwater depth
Authors: Alwan Naseer T , Shcheklein S E , Ali Obed M
Published: December 2020

The solar still's productivity affected by various conditions such as design, operational and environmental conditions. The current study aims to investigate the effect of water depth on the suggested solar still productivity. The results showed that the productivity decreased with increasing the basin water depth from 1 cm to 3 cm, and the higher freshwater productivity obtained at lower water depth. It is found that the productivity of solar still at 1 cm water depth started early in comparison with the other two depths (2 and 3 cm), the highest distillate for the three perfect days it was recorded with the lowest water depth of 1 cm, while the lowest distillate was with the largest depth 3 cm. Accumulated distillate during 10 hours from 8:00 am to 18:00 pm was 1.6,1.35 and 1.05 L/m
2, for three perfect days 20, 22 and 24.03.2019 and for the three water depths 1, 2 and 3 cm, respectively. the estimated production cost of one liter of freshwater form single slope solar still model found to be 0.033 $, 0.041 and 0.05 $ with 1, 2 and 3 cm water depths respectively.
Restoring function of the orbiting electron wave packet
Authors: Kumar Vineet
Published: December 2020

About the reference line as a closed curve along which electron moves at a discrete distance from the nucleus of atom, if asked, locally, is there any distribution alike then it is simple to answer yes. This is due to the group of wave of electron protrudal as wave packet. Revolving around the nucleus with certain kinetic energy determines the peculiar wave length, in a way that higher the energy lower the wavelength is as suggested by de Broglie, does this means that with respect to local points on closed curve the energy is distributed to every wave lines, yes it means. But, when asked in comparative to classical spring-mass oscillating system revolving, is there any restoring part in the orbiting electron wave packet then this is important to know. This paper based on the velocity operator cataloging along with its correspondence to energy-frequency relation discuss about the restoring function of orbiting electron wave packet and its importance in the orbital angular momentum.
Influence of quantum correction on the Jeans instability of strongly coupled magnetized plasma
Authors: Dashora R , Pathan T A , Sutar D L , Pensia R K , Patidar A K
Published: December 2020

It is shown that the Jeans instability condition of strongly coupled finitely conducting gaseous plasma is reduced in the presence of magnetic field and quantum correction. The linearized equations are constructed by using the Quantum magneto-hydrodynamic (QMHD) model. With the help of the normal mode analysis method, a general dispersion relation is obtained. This dispersion relation is discussed by a different mode of propagation. In this paper, it has been found that, quantum correction stabilizes the growth rate of the organization but the relaxation time and electrical resistivity destabilize the growth rate in the transverse mode of propagation. Further, the modified Jeans criterion of the instability of the magnetized plasma system has been also found.
Green synthesis of silver nanoparticles from Justicia adhatodaplant extract with its diverse properties
Authors: Rajalekshmi  , Lohithan Roshny , Raj Rakhi , Prakash Priyanka , Santosh Abhirami , Theertha V , Chandran Smitha
Published: December 2020

In the past few years, the science of nanostructure and technology has gained magnificent attention in the worldwide area of research and technology because of its capability to show various applications which are high thermal and electrical properties, magnetic properties, optical properties, catalytic properties, mechanical properties etc. These properties suits them for different technology and uses such as drug design, pharmaceuticals, space applications, cosmetics, medical industries, photo imaging, nano sensors used for the detection and monitoring of biomolecules. It is also suitable in the environmental field of mosquiticidal, antimicrobial properties. This article is basically focused on the synthesis of silver nanoparticles in a greener procedure by using the leaves of Justicia adhatoda (also called as Malabar nut) which is a medicinal plant used for cough, asthma, allergic conditions, excessive uterine bleeding, heavy menstruation etc. and is seen in various parts of India. The silver nanoparticles once synthesized were characterized using UV-Visible spectroscopy and XRD technique. Later, the particles were analysed for antimicrobial activity against two strains of microorganisms. This greener method that we used is simple, economically feasible, environment friendly and does not produce any harmful substances.
Chemical and electrochemical corrosion studies of ricinus communis oil based poly(urethane-ricinoleamide) coatings
Authors: Kashif Mohd , Anjum Ansar
Published: December 2020

In view of the depletion and possible exhaust of fossil fuels in near future, enormous increase in the cost of petroleum products and production of volatile organic compounds (VOC) by synthetic polymers and their application, the proposed article reports the development of sustainable resource based high performance Ricinus communis oil (Castor Oil) [RC] poly(urethane-ricinoleamide) [PUR] corrosion resistant coatings on mild steel. The physico-mechanical properties were investigated using standard methods. The corrosion resistance performance of PUR coatings was evaluated by weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in acid (3.5 wt% HCl) and alkaline (3.5 wt% NaOH) mediums. The weight loss measurement was also carried out under tap water (Cl- ion 63 mg/l; Conductivity 0.953 mS/A). Salt mist test (5 wt% NaCl) was performed on these coatings. The effect of additional –OH functionality of RC oil on the corrosion resistance performance of PUR coatings was also discussed. These investigations reveal that the PUR coatings provide protection to the mild steel by reducing the corrosion current density by 104 times as compare to bare MS. These coatings also exhibits higher corrosion resistance performance as compared to other reported sustainable resource based coating systems, hence show good potential for their commercial application.
A review: high power density motors for electric vehicles
Authors: Sudha B , Vadde Anusha , Sachin S
Published: December 2020

The review of High Power Density Motor (HPDM) is presented, the high power density refers to ratio of output power to volume of the motor. As a result even a small envelope motor can have high power output. HPDM are also known as low speed high torque motors. The HPDM are compact, lightweight, has high torque and less cogging torque, finding application in automotive field, especially in electric and hybrid electric vehicles. This paper analyses the design, performance and efficiency of various HPDM. Comparative analysis of thirteen different HPDM are reviewed and tabulated for power density, speed, weight, rating and its applications.
Appraisal of motion estimation techniques in video compression
Authors: Aruna J , Jeyalakshmi C , Priyadarshini K
Published: December 2020

In this paper, plan to propose a new motion estimation technique similar to that of estimation methods such as full search 3ss,4ss, block matching approaches and parametric motion estimation. Motion Estimation is mainly used to estimate the motion or error in an object. It can easily identify and tracks the movements of object in a frame. In this paper to present a detailed survey of motion estimation techniques and various methods of searching methodologies are also analyzed. Investigation shall also be carried out to estimate the motion to enrich the quality of decompressed video by analyzing the compression error. A study on not only the design of new motion estimation algorithm but also error free compression is going to be the main objective.
Miniaturized cpw-fed conformal antenna for guided missiles
Authors: Gopi Dattatreya , Chandra A R G , Mouli K , Janardhan Reddy V , Chaitanya G K , Ramu S
Published: December 2020

A conformal wing-shaped patch (WSP) antenna is designed and investigated in this paper. Coplanar waveguide (CPW) feed is used to get high impedance matching and better radiation pattern. The WSP antenna is designed on Kapton polyimide substrate material measuring 20 × 30 × 0.1 mm3. It offers the impedance bandwidth of 630 MHz (6.55 GHz -7.18 GHz), 560 MHz (9.80 GHz -10.36 GHz), 560 MHz (9.80 GHz -10.36 GHz) at resonant frequencies 6.97 GHz, 10.12GHz, 15.78GHz respectively. The reflection coefficients are obtained at -17.42 dB, -16.39dB, -18.23dB for the resonant frequencies. To analyze the conformability of the WSP antenna, the model is tested by mounting on the guided missile. The performance of the antenna is good and small deviations are observed with a shift of 30 MHz, 120MHz, 380MHz in the reflection coefficient. The compactness and conformal design with multi-band support proves the antenna suitable for future military applications.
Study of hybrid median filter for the removal of various noises in digital image
Authors: Sreejith Shwetha , Nayak Jagadish
Published: December 2020

The aim of this study is to construct a hybrid median filter using MATLAB and use that filter to remove impulse noise from an image, in order to produce an enhanced image. This is done in order to show how a hybrid median filter can be a more optimal option than a conventional median filter for removing impulse noise.
Performance analysis of AGSM adaptive unipolar MIMO-OFDM for visible light communication
Authors: Yadav Devendra Pratap , Singh Harshit , Keshri Aditya , Prakash Kaustubh , Singh Vinay
Published: December 2020

Visible light communication is a leading technology in wireless communication which provides free spectrum with high data rate. In this paper, improvement of the data rate is achieved in the adaptive transmission for U-OFDM system which works on switching of various MIMO modes. In VLC system different MIMO modes give different performance on the basis of their modulation size. The adaptive system switches between spatial modulation (SM), spatial multiplexing (SMUX), repetition code (RC) and adaptive generalized spatial modulation (AGSM) MIMO modes on the basis of received SNR and target Bit Error rate to attain high spectral efficiency (χ). The performance of adaptive generalized spatial modulation mode is analysed and compared with the three modes (RC, SM, SMUX) over 2×2, 4×4, 8×8 MIMO systems in realistic channel models. The simulation results show that significant improvement in data rate and spectral efficiency is achieved using AGSM MIMO mode in comparison to SM, RC and SMUX MIMO modes.
A miniaturized antenna array for direct air-to-ground communication of aircrafts
Authors: Shashi Kumar D , Suganthi S
Published: December 2020

In this paper, a miniaturized, high directivity low-cost antenna array is presented. The uniqueness of the proposed array (PA) exists in the feed mechanism designed using Dolph-Chebyshev non-uniform excitations. Authors simulated the designed antenna array using ANSYS EM 18.2 (HFSS) software and characterization is carried out in a fully established anechoic chamber. The simulated array antenna is operating at 2.4 GHz with a gain of 8.12 dB and a reflection coefficient of -28.45 dB having a bandwidth of 110 MHz. On contrast with the traditional array (TA), PA exhibits enhanced resonance characteristics by maintaining the same radiation characteristics. The bandwidth is increased by 37.5%, maintaining the same gain of 8.12 dB. In contrast, there is a remarkable reduction in the size compared to the traditional corporate feed array antenna with non-uniform excitation. The overall size of the PA antenna is 242.5 mm × 58.8 mm, which is 33.73% less compared to the TA.
Signal Analysis and Filtering using one Dimensional Hilbert Transform
Authors: Dankan Gowda V , Naveena Pai G , Sridhara S B , Shashidhara K S , Gangadhara
Published: December 2020

In the ground of Digital Signal dispensation, the discrete Hilbert Transform has found more and more important. The representation of a signal as the real part of a complex function in time is very much useful in many areas of signal analysis. In this paper, the demonstration of a significant improvement of a real seismic signal in the form of the complex envelope (amplitude and phase ) which may be obtained by using the discrete Hilbert transform techniques. The pulse here considered for the study is similar to the Berlage function that is used to replicate seismic signals. In addition to this, it also presents discussion on the application of Hilbert transform on the spectral factorization which is related to the minimum phase and inverse filters.
Design of STATCOM for reactive power control using multilevel inverter
Authors: Lazar Amal , Chandel Ashwani Kumar
Published: December 2020

STATCOM a power electronic based device is widely used for reactive power compensation. In the present work, a STATCOM is realized by employing a 3-level neutral point clamped inverter which is controlled by space vector pulse width modulation technique. Switching sequence for STATCOM is designed by minimizing the deviation in neutral voltage. Subsequently, the STATCOM is connected to the load side of a power network and by varying source voltage, reactive power control is accomplished resulting in voltage control of load side and improving the power quality of the network. The present work will be useful to the utilities dealing with reactive power and voltage control of AC transmission networks.
Evaluation the current specifications for bridge in mountainous area of Vietnam
Authors: Nguyen Xuan Tung , Hoang Viet Hai
Published: December 2020

Vietnam area is more than 320,000 square kilometers and three – forth are mountainous area. The transportation in this mountainous is very hard. Due to the mountainous geography, there is a lack of bridge which allow pedestrian or low – loading vehicle passing through. Besides the technical specification that was officially issued only cover the bridge on Highway and rural road. In this paper, the results of survey of bridge condition at 3 mountainous provinces is introduced and the evaluation of current specification, the basic technical specifications for mountainous bridges are also proposed.
Foundations of wind power plants - challenges in designing and execution of construction work
Authors: Rybak Jaroslaw
Published: December 2020

The paper is focused on foundations of wind turbines and challenges in design, execution and long-term maintenance. Some typical solutions are listed: footings (round plates) on natural soil, footings on modified soil (DSM, stone columns, CMC) and deep foundations (piles). The author juxtaposed basic problems that appear in design phase: data acquisition for various kinds of foundations, appropriate calculation model and possibility of on-site verification and possible changes. Problems appearing during execution of works are illustrated with examples of service roads arrangement, earth works (excavations) and soil improvement or piling. The author emphasized the role of quality control including: monitoring of soil conditions and groundwater level at execution stage and impact of earth works – re-profiling of ground level. In final remarks, some recommendations are given for current control of quality (ground parameters, soil improvement, piling) and long-time maintenance – possible problems in foundations related to: time, cyclic loading and changes in the soil related to previous earthworks.
Assessment and prediction of PM10 concentration using ARIMA
Authors: Hosamane Sateesh N , Prashanth K S , Virupakshi Arjun S
Published: December 2020

Urban air pollution is rapidly becoming an environmental issue of global concern, affecting public health, regional weather, and climate. The air quality crisis in cities is mainly caused by vehicle emissions. A city's air quality is assessed using the Air Quality Index (AQI), which analyses concentrations of air pollutants such as PM10, sulphur dioxide SO2, and nitrogen dioxide NO2. The current study on air pollution was carried out in the SG Halli area of Bangaluru and required air pollutant data was collected from the Karnataka State Pollution Control Board (CPCB). With the exception of PM10, the pollutant concentration was within the permissible limits set by the Central Pollution Control Authority (CPCB). Pollutant concentrations were analyzed using meteorological variables such as relative humidity (RH), temperature (T), wind direction (WD), wind speed (WS), and solar radiation (SR). PM10 concentrations are predicted using an auto-regressive integrated moving average (ARIMA) model. PM10 concentrations were well predicted by ARIMA model. On the AQI scale, it can be seen that the atmospheric environment of SG Halli is moderately polluted.
Effect of nickel containing mixing water on the properties blended cement mortar
Authors: Madhusudana Reddy B
Published: December 2020

Influence of Nickel(Ni) present in the water which is used for mixing of blended cement was experimentally evaluated. The properties investigated were setting times, soundness, compressive strength, and durability aspects like acid attack, alkaline attack and sulphate attack. Specimens were prepared by using the de-ionized as well as Nickel(Ni) spiked de-ionized water for reference and the test samples respectively. The concentrations of Nickel(Ni) tested for different samples are 10, 50, 100, 500, 1000, 2000, 3000, 4000 and 5000mg/L. It is observed that on comparison with reference specimens, the setting process of cement of test specimens has increased with increase of Nickel proportion in de-ionized water. Increase of initial setting time was insignificant up to 100 mg/L concentration whereas the same for final setting time was significant for all concentrations. Change in expansion of cement mortar is insignificant up to 3000 mg/L concentrations of the Nickel(Ni). The change in strength was noticed to be insignificant at all the concentrations of Nickel(Ni). However, there is an increase in strength with higher Nickel proportion up to 2000 mg/L. This proportion of 2000 mg/L was considered as the reference mix for conducting durability tests. The strength as well as weight loss for the specimen mortar cubes placed in acidic medium are severe compared to that of alkaline and sulphate solutions with increase in age.
Solving reliability redundancy allocation problem using grey wolf optimization algorithm
Authors: Rakhi  , Pahuja G L
Published: December 2020

This work presents a metaheuristic approach of solving Reliability-Redundancy-Allocation- Problem (RRAP) of a system using Grey Wolf Optimization (GWO) algorithm. The RRAP is restructured here for different configurations of a system such as series, series-parallel, bridge, and a practical system of over-speed protection. The solution of RRAP provides the decision in selecting the optimal number of redundant components with the corresponding reliability level of each subsystem to maximize the overall reliability of a system subjected to non-linear resource constraints. The proposed approach using the GWO algorithm provides better results with higher exploration and exploitation capability of search space than the existing solutions in the literature. Further, with the computation of Maximum Possible Improvement (MPI) using other optimization methods, it is evident that GWO solves the RRAPs efficiently and delivers maximum reliability of the system with an optimal selection of components.
Aspect of join ingress authority for civic directory
Authors: Rajaprakash S , Muthuselvan S , Bagath Basha C , Kesshika A , Pavithra E
Published: December 2020

T Nowadays, Cloud computing is a major and emerging platform that provides various IT related services. The two major factors which inhibit the growth of cloud computing are privacy and security. Hackers can break into public or private cloud environment and steal the data. They can use it with malicious intent such as either use or sell the sensitive information obtained from the business cloud environment. Hence, user’s safety depends upon security level in cloud service providers. For an enterprise, there are enormous amount of data is stored and most of them are sensitive information which can affect huge number of people or an entire business organization. Networks are the medium through which all tasks are performed. For access control, being one of the classic research topics, various schemes have been proposed and implemented. In existing key policy, when the key which provides access to the data falls into the wrong hands, they can use it with malicious intent such as steal or alter the data or sell the sensitive information obtained from the business cloud environment. Using our proposed algorithm, we can able to provide a collaborative access control scheme for public cloud storage. This system is implemented using encryption method called Attribute Based Encryption. Encrypting data ensures that even if the data falls into the wrong hands, it is useless as long as its keys remain secure. Even when the hacker gets access to the key, he cannot access the data as only the assigned users can access the data using the key.
Performances of non-parameterised radial basis functions in pattern recognition applications
Authors: Tavaen S , Viriyapong R , Kaennakham S
Published: December 2020

Pattern recognition appears in many applications with most popular scheme are those involved the so-called ‘Radial Basis Function (RBF)’. It is known that the shape parameter contained in some RBFs used has great influence on the final quality of prediction. This study focusses on RBFs which contains no parameters where three data patterns are used for performance validation. With a good choice of number of centres, it is clearly possible to obtain satisfactory results with no burden on choosing the suitable or optimal shape. This can well shed more light into applications with more complexity with less user’s judgment and be more automatic in the process.
Effect of feed and step depth in hole flanging using single point incremental forming
Authors: Makwana Rudreshkumar , Modi Bharat , Patel Kaushik
Published: December 2020

Single Point Incremental Forming can be used to form hole flanges in automobile and aerospace applications. In hole flanging using single point incremental forming, a study on effect of feed and step depth on formability has been carried out. Hole flange thickness is taken as formability criterion. Moreover, effect of those parameters on surface roughness has also been studied to understand effect of Single Point Incremental Forming. The results obtained by experimental work were analyzed and are presented here.
Comparative study on the effect of single coil and multi coil magnetorheological damper through finite element analysis
Authors: Kariganaur Ashok Kumar , Kumar Hemantha , Mahalingam Arun
Published: December 2020

Magnetorheological damper is vibration reducing system in which the magnetorheological fluid is the operating liquid which changes its behaviour with external stimulus by increasing the yield stress of fluid with the application of external magnetic field. Most of the vibration reducing equipment’s is operated with single coil, and in this paper, study of multi coil magnetorheological damper is discussed and compared with the single coil for its magnetic flux density of the applied currents is studied by dividing equal and unequal number of turns of the coil in multi coil unlike in single coil damper.
A review on erosion of a Pelton turbine bucket
Authors: Shah H A , Chaudhari G C , Dhiman V D , Ansari F S , Pathak M N
Published: December 2020

Hydro-power energy is the most efficient renewable energy sources in the world. India stands in the top ten hydropower generation countries list. Pelton turbine is a well-known hydropower extraction machine. The Pelton turbine buckets play an important role in the efficiency of the hydro turbine which is in continuous interaction with high velocity jet and there are possibilities of damages to the bucket in the form of erosion as water contains small debris as sediments. Eroded buckets greatly reduce the efficiency of the turbine. Attempt is made by researchers to developed co-relations to evaluate wear rate and efficiency reduction based on the practical data. The majority of erosion takes place at splitter areas. An erosion cannot be eliminated, but it can be reduced by some amount. The results of the mathematical model indicate that the effect of silt size to the wear rate is 0.0001 gram per gram of bucket weight for a particular silt concentration and the result of silt concentration to wear rate is 0.0007 gram per gram of bucket weight for a particular silt size. The normalised efficiency loss is increased to 0.13% for a specific silt size with the variation of silt contraction. The average wear rate is nearly 3.1 mm per year for laboratory-scale Pelton turbine bucket; which is manufactured from brass and bronze materials. The coating of various materials over the buckets are used by researchers to reduce erosion. Among all coating materials, WC-Co-Cr gives better results against erosion.
Redesign of computer workstation using ergonomics
Authors: Sreerag A , Arunkumar S , Jayadeep J , Pereira A H
Published: December 2020

Today’s world is mostly occupied on computers, for which the workstation must be more comfortable to the operators. The objective of this paper is to develop a new design of a computer workstation (upright position) for preventing health risks associated with conventional workstations. The redesigned workstation incorporating ergonomics enhances the motivation, performance and productivity of the operator without affecting health. The vital requirements of computer workstation specified in various literature as per the standards for providing comfort to users is briefly presented. In addition, the product must be manufactured at less cost. To accomplish this design for manufacture and assembly (DFMA) principles are employed. Finally, the integrity of the redesigned workstation is analysed using simulation software.
Effects of hot forging and subsequent carburisation on low-carbon steels.
Authors: Srivastava Sanchit , Lembhe S D
Published: December 2020

The research intends to work on the increasing hardness of low carbon steels by a congregation of box carburisation with different combination of low carbon steels that have been initially reduced to a certain volume vis-a-vis hot forging.There has not been ample work that look at a combination of hot forging and carburisation and hence this paper is a comparative study of the increase in surface hardness of three metal surfaces at three different steps- when low carbon steels are just carburised; only forged and when the materials go both carburisation and forging. The research is conducted on three different metals(MS, EN8,SAE8620) and Vicker’s Hardness Tester was solicited for hardness testing and conclusions in terms of hardness and case depth rallied with plunge in the volume of the metals.
Increased Amazon Basin wet-season precipitation and river discharge since the early 1990s driven by tropical Pacific variability
Authors: Friedman Andrew R , Bollasina Massimo A , Gastineau Guillaume , Khodri Myriam
Published: December 2020

The Amazon Basin, the largest watershed on Earth, experienced a significant increase in wet-season precipitation and high-season river discharge from the early 1990s to early 2010s. Some studies have linked the increased Amazon Basin hydrologic cycle to decadal trends of increased Pacific trade winds, eastern Pacific sea surface temperature (SST) cooling, and associated strengthening of the Pacific Walker circulation. However, it has been difficult to disentangle the role of Pacific decadal variability from the impacts of greenhouse gases and other external climate drivers over the same period. Here, we separate the contributions of external forcings from those of Pacific decadal variability by comparing two large ensembles of climate model experiments with identical radiative forcing agents but imposing different tropical Pacific wind stress. One ensemble constrains tropical Pacific wind stress to its long-term climatology, suppressing tropical Pacific decadal variability; the other ensemble imposes the observed tropical Pacific wind stress anomalies, simulating realistic tropical Pacific decadal variability. Comparing the Amazon Basin hydroclimate response in the two ensembles allows us to distinguish the contributions of external forcings common to both simulations from those related to Pacific trade wind variability. For the 1992–2012 trend, the experiments with observed tropical Pacific wind stress anomalies simulate strengthening of the Walker circulation between the Pacific and South America and sharpening of the Pacific–Atlantic interbasin SST contrast, driving increased Amazon Basin wet-season precipitation and high-season discharge. In contrast, these circulation and hydrologic intensification trends are absent in the simulations with climatological tropical Pacific wind stress. This work underscores the importance of Pacific decadal variability in driving hydrological cycle changes and modulating the hydroclimate impacts of global warming over the Amazon Basin.
Assessing the long-term interactions of climate change and timber markets on forest land and carbon storage
Authors: Favero Alice , Mendelsohn Robert , Sohngen Brent , Stocker Benjamin
Published: December 2020

This study provides a comprehensive assessment of the environmental and economic impacts of climate change on global and regional forests from now through 2200. By integrating the representative concentration pathway (RCP) 2.6 and RCP 8.5 emission scenarios with climate models, a vegetation model, socio-economic scenarios, and a forest economic model, the study explores long run adjustments of both ecosystems and markets to climate change that have not been studied before. The ecological model suggests that global forest productivity increases under RCP 8.5. The overall supply of timber expands faster than demand through the 23rd century lowering timber prices and creating net benefits in the timber sector. Consumers benefit the most from the lower prices but these same low prices tend to damage forest owners, especially in the tropics. Even without a formal sequestration policy, average global forest carbon is projected to increase by 6%–8% by 2100. Under the RCP 2.6, forest carbon remains stable through 2200 but under RCP 8.5 it is simulated to increase by another 8% with a very heterogeneous distribution across world regions. Under both RCPs, global forest area is projected to increase relative to a no-climate change case until 2150, but possibly decline thereafter.
Snowpack signals in North American tree rings
Authors: Coulthard Bethany L , Anchukaitis Kevin J , Pederson Gregory T , Cook Edward , Littell Jeremy , Smith Dan J
Published: December 2020

Climate change has contributed to recent declines in mountain snowpack and earlier runoff, which in turn have intensified hydrological droughts in western North America. Climate model projections suggest that continued and severe snowpack reductions are expected over the 21st century, with profound consequences for ecosystems and human welfare. Yet the current understanding of trends and variability in mountain snowpack is limited by the relatively short and strongly temperature forced observational record. Motivated by the urgent need to better understand snowpack dynamics in a long-term, spatially coherent framework, here we examine snow-growth relationships in western North American tree-ring chronologies. We present an extensive network of snow-sensitive proxy data to support high space/time resolution paleosnow reconstruction, quantify and interpret the type and spatial density of snow related signals in tree-ring records, and examine the potential for regional bias in the tree-ring based reconstruction of different snow drought types (dry versus warm). Our results indicate three distinct snow-growth relationships in tree-ring chronologies: moisture-limited snow proxies that include a spring temperature signal, moisture-limited snow proxies lacking a spring temperature signal, and energy-limited snow proxies. Each proxy type is based on distinct physiological tree-growth mechanisms related to topographic and climatic site conditions, and provides unique information on mountain snowpack dynamics that can be capitalized upon within a statistical reconstruction framework. This work provides a platform and foundational background required for the accelerated production of high-quality annually resolved snowpack reconstructions from regional to high (

<

12 km) spatial scales in western North America and, by extension, will support an improved understanding of the vulnerability of snowmelt-derived water resources to natural variability and future climate warming.
Monitoring cumulus clouds by using global horizontal irradiance data
Authors: Zuev S V , Krasnenko N P
Published: December 2020

A previously proposed method for the detection of cumulus clouds by using time series of global horizontal irradiance from a pyranometer is developed. A characteristic feature of this method is the acceptance of short 21-minute moving analysis windows as stationary. This approach makes it possible not to construct a clear sky model for transforming a non-stationary daily time series of global horizontal irradiance to stationary time series.
Special aspects of snow cover formation in Western and Eastern Siberia
Authors: Martynova Yu V
Published: December 2020

Some features of snow cover onset in the autumn-winter season in Western and Eastern Siberia are presented. Snow cover extent data from NOAA historical satellite records are used in this study. The dates of onset and termination of snow cover, as well as the period of the most intense snow cover area increase during the season and its rate are revealed. The interannual variability of these parameters is estimated. The variation of the October snow cover area is also considered. A significant positive trend has been obtained, as well as a linear relationship with the date of the beginning of the week with the highest rate of snow cover increase during the season.
Long-term dynamics of snow cover in the Baikal region
Authors: Matyukhina A A , Voropay N N
Published: December 2020

An analysis of long-term changes in the depth (maximum, average), the dates of onset and destruction, and the duration of stable snow cover in the Baikal region is carried out according to data of observations at weather stations in 1959–2019, which makes it possible to reveal the differences of these characteristics on the eastern and western coasts of Lake Baikal. A maximum long-term snow cover depth of 39 -175 cm is recorded at weather stations in the eastern Baikal region with an average long-term depth of 9.1 -80.8 cm. At weather stations in the western Baikal region, the maximum long-term snow cover depth is 21-67 cm with average long-term values of 4.5-30.3 cm. A close dependence of the duration of snow cover on the dates of its onset and destruction has been found. At the end of the study period, a shift in the dates of onset and destruction of snow cover to earlier dates is observed in the absence of statistically significant trends. As a result of these changes, snow cover melts earlier and the duration of its occurrence is significantly reduced. The average long-term duration of stable snow cover on the territory of the Baikal region is 182 days: 186 days in the east, and 173 days in the west.
Characteristics of mesoscale eddies of Arctic marginal seas: results of numerical modeling
Authors: Platov Gennady , Golubeva Elena
Published: December 2020

A simple method is proposed for identifying mesoscale eddies in the results of numerical modeling. The method uses extrema in distributions of the sea level elevation as eddy markers. By using the method, we analyze statistics of mesoscale eddies resulting from SibPOM numerical simulations in the Eurasian sector of the Arctic marginal seas. The results of using this method show that the number of cyclonic eddies slightly exceeds the number of anticyclonic eddies, but the excess is only 2-3%. Also, we demonstrate that a significant number of eddies arise under the ice cover. The number of such eddies increases significantly in winter. This fact indicates that the convection caused by salt rejection during freezing plays an essential role in their formation. The numerical modeling results confirm the phenomenon of active eddy generation in the ice edge zone. Besides, the results show that in the near-edge zone, a more significant number of eddies are formed from the icy side adjacent to the edge, and not from the ice-free side. The periods of seawater freezing and ice melting, accompanied by corresponding displacements in the ice edge, produce eddies different in nature. The number of eddies in the marginal ice zone has two seasonal maxima corresponding to these two periods.
Numerical simulation of turbulent mixing and transport of biochemical substances in inland waters
Authors: Gladskikh D S , Mortikov E V , Stepanenko V M
Published: December 2020

Numerical modeling of inland water objects (lakes and reservoirs) and, in particular, mixing processes and transport of biochemical substances in these basins is considered. A three-dimensional hydrostatic model and a one-dimensional model LAKE based on averaging of three-dimensional equations over a horizontal section of a reservoir are used as tools for the calculations. In the LAKE model, seiche oscillations are taken into account by parameterizing the pressure gradient and horizontal eddy viscosity. A k-ε closure is used to describe the vertical exchange processes in both models. A parameterization of the Prandtl number is implemented in the 3D model which allows turbulence to persist at any values of the gradient Richardson number. The 3D model is also supplemented by equations for calculating biochemical substances by analogy with the one-dimensional biochemistry equations used in the LAKE model, which, in particular, allow us to study the transport of substances such as oxygen (O2) and methane (CH4). Numerical experiments aimed at studying turbulent mixing and transport of substances are carried out.
Assessment of the influence of various tree species and their parameters on the behaviour of wind flows in urban environments (on the example of the RUDN University campus, Moscow)
Authors: Bukin S S , Fadeeva I A , Yaroslavtsev A M , Konstantinov P I , Vasenev V I , Valentini R
Published: December 2020

Urban environments are constantly growing, as a result of which natural surface covers are replaced by artificial materials. These changes have a strong impact on the wind fields in these urban environments, changing speeds and directions of wind flows. The aim of this study is to assess the effects of various tree parameters on the behaviour of wind flows in an urban environment. The EnviMet software package is used to model wind fields. The study is conducted in the city of Moscow on the RUDN University campus. Ten different kinds of trees are identified with characteristics such as tree height, crown width, trunk height, and the LAD (Leaf Area Density) index. For these species, a similar analysis is carried out to assess their impact on the wind field. The height of the trunk has a significant effect on the wind field at the pedestrian level; depending on the parameter, the wind speed and the area of wind gusts increase. Large crowns create a protective barrier, reducing wind activity. At the same time, a high LAD index creates low wind permeability, as a result of which the wind flows are refracted, and dangerous zones arise. On the other hand, a high LAD index reduces the area of wind gusts.
Microscale simulation of wind speed in urban areas during extreme weather events (case study of Moscow)
Authors: Nikolaeva E V , Kospanov A A , Bukin S S , Konstantinov P I
Published: December 2020

This study is primarily based on the goal to make a model of the MSU campus to investigate wind speed distribution. As a case study, a squall event on the 29th of May 2017 is chosen. The event caused human casualties, which required much research. To validate the results, they have to be tested for their stability. In this work this goal is met by varying wind directions. Later the wind maps were achieved as the results were overlaid to reflect the variability of the wind speed distribution. Moreover, the results of this work are possible dangerous areas of a campus which can be obtained as a result of simulating hazardous wind speeds. The wind directions are varied to match 4 primary directions. The heights of interest are chosen to be 1.5 m and 12.5 m, they represent the pedestrian level and the level of half the average tree height, respectively. The simulation software used is ENVI-met. This work shows whether this software is suitable for modeling hazardous events, how stable the results are, and whether the new user is able to successfully use the possibilities offered by ENVI-met to achieve the needed goals. With the results of simulations for stability tests and dangerous area outlining, spatial distributions of the wind speed are analyzed both quantitively and qualitatively.