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Numerical investigation of the effect of transitory strand opening on mixing in a multistrand tundish

International Journal of Minerals,Metallurgy and Materials 2011年第5期18卷 535-542页

作者： Sabin Kumar Mishra Pradeep Kumar Jha satish Chandra sharma satish Kumar Ajmani Department of Mechanical and Industrial Engineering Indian Institute of Technology RoorkeeRoorkee 247667UttarakhandIndia Steelmaking and Casting Research Group Tata SteelR&DBurma MinesJamshedpur 831007JharkhandIndia

In a multistrand,the outlet near the inlet produces short circuiting *** leads to the formation of dead zones inside the tundish,and consequently,the mean residence time *** the present study,numerical investigation of mixing inside a delta shaped tundish with sloping boundaries was carried out by solving the Navier-Stokes equation and employing the standard turbulence *** decrease the dead zone volume inside the tundish,the effect of closing the outlet near the inlet for a small amount of time and further opening it on the mixing behavior of the tundish was *** outlets near the inlet were closed for varying amount of time,and the transient analysis of fluid flow and the tracer dispersion study were carried out to find the mixing parameters of the tundish,namely,mean residence time and the ratio of mixed to dead volume of the *** optimum closure time of the near outlet has been found,which yields best mixing inside the *** numerical code was validated against the experimental observation by performing the tracer dispersion study inside a multistrand tundish and the reasonably good match between the experimental and numerical results in terms of residence time distribution （RTD） *** results obtained from the present study confirm the strong role of choosing the right time for opening and closing the outlets to get improved characteristics for the fluid flow and mixing behavior of the *** educational version of computational fluid dynamics （CFD） software PHOENICS was used to solve the governing equations and interpret the results in different forms.

关键词： continuous casting billets tundish flow simulation mean residence time dead volume computational fluid dynamics (CFD)

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Effect of cooling media on bead geometry,microstructure,and mechanical properties of wire arc additive manufactured IN718 alloy

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Advances in Manufacturing 2024年第1期12卷 124-149页

作者： Parveen Kumar satish Kumar sharma Ratnesh Kumar Raj Singh Department of Mechanical Engineering Thapar Institute of Engineering and TechnologyPatialaPunjab147004India

This work aims to present and explore thermal management techniques for the wire arc additive manufacturing(WAAM)of IN718 *** heat can be mitigated via air or water *** this study,the material was deposited under four different heat-input conditions with air or water *** air cooling,the layer is deposited in a normal atmospheric air environment,whereas with water cooling,the material is deposited inside a water tank by varying the water *** validate the air and water cooling thermal management techniques,IN718 single-pass and multilayer linear walls were deposited using the bidirectional gas metal arc welding based WAAM setup under four different heat input *** the deposition of single layers,the temperature profiles were recorded,and the geometric and microstructural features were *** multilayer wall structures,the mechanical properties(hardness,tensile strength,and elongation)were determined and assessed using the corresponding microstructural features explored through scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),and electron backscatter diffraction(EBSD)*** microstructure observed through SEM analysis in the building direction was found to be nonhomogenous compared with that in the deposition ***,water cooling was found to govern bead characteristics,such as wall width and *** grain size and anisotropy of the mechanical properties also decreased in the water-cooled ***,water cooling is an economical and efficient method to mitigate excessive heat accumulation in WAAM-deposited IN718.

关键词： Air cooling Water cooling IN718 Bead characteristics Microstructure Electron backscatter diffraction(EBSD)

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Microscopic and macroscopic diagnosis of the effect of winter weather conditions on distribution pattern of truck types in regional commuter road

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Journal of Modern Transportation 2018年第1期26卷 57-71页

作者： Hyuk-Jae Roh satish sharma City of Regina Old Fire Hall #1 1640 11th AvenuePO Box 1790 Regina SK S4P 3C8 Canada University of Regina Regina SK Canada

It has been reported in the past literature that total traffic volume and passenger car volume are affected by snowfall and cold temperature, but trucks are not sig- nificantly affected. This paper aims to confirm that the distribution of truck types is not affected by winter weather conditions through combined statistical analysis in the framework of microscopic and macroscopic impact anal- ysis. A micro-level analysis was conducted to investigate the effect of snowfall and temperature on changes in truck type distribution. A macro-level analysis was also con- ducted to investigate the effect of the months （or seasons） on changes in truck type distribution. Truck traffic data were collected for 5 years at the weigh-in-motion site in Highway 2A, which is used for regional commuters near the City of Leduc, Alberta, Canada. The trucks were sub- divided into straight unit truck, single trailer and multi trailer unit and then analyzed by applying a nonparametric Chi-squared test combined with the binomial probability test. As a result of the nonparametric test, the truck type distribution was stable irrespective of the severity of winter weather conditions, which are microscopic factors such as snowfall and temperature, and was not influenced by changes in months and seasons, which are macroscopic factors.

关键词： Truck traffic Inclement weather Regionalcommuter road Weigh in motion Snowfall Temperature

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Modal analysis of prestressed draft pad of freight wagons using finite element method

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Journal of Modern Transportation 2015年第1期23卷 43-49页

作者： Sachin Sudhakar Harak satish Chand sharma Suraj Prakash Harsha Vibration and Noise Control Lab. Mechanical and Industrial Engineering Department Indian Institute of Technology

The present work intends to investigate dynamic behaviour of draft gear using finite element method. The longitudinal force that the draft gear absorbs usually leads to the failure of its components, especially, the load bearing draft pads. Dynamic behaviour of an individual draft pad and a draft gear is determined and characterized with exciting frequen- cies and corresponding mode shapes. The effect of compressive prestress load on the dynamic behaviour of an individual draft pad is also determined as the draft pads in assembled state are under constant axial compressive force in the draft gear. The vibration characteristics of individual draft pad are compared with draft pads that are part of draft gear. The modal analysis gives us a basis for subjecting a draft pad to higher frequency loading for determining its fatigue behaviour.

关键词： Draft gear. Draft pad. Prestress Naturalfrequency Mode shapes Finite element method

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Case study scenarios in site selection of hazardous material facilities based on transportation preferences

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Journal of Modern Transportation 2019年第4期27卷 317-333页

作者： Babak Mehran Musharraf Ahmad Khan Mina Mehran Hyukjae Roh satish sharma Department of Civil Engineering University of Manitoba66 Chancellors CirWinnipegMB R3T 2N2Canada Faculty of Engineering and Applied Science University of Regina3737 Wascana PkwyReginaSK S4S 0A2Canada City of Regina 2476 Victoria AvenueReginaSK S4P 3C8Canada

A methodology is proposed to evaluate and rank potential sites for facilities dealing with hazardous materials(HAZMAT).The proposed methodology incorporates HAZMAT route planning into facility siting while considering transportation preferences and *** area of interest is divided into smaller zones representing potential sites for a HAZMAT facility.A multimodal transportation network including railways and roads is considered for transportation of *** zone is evaluated based on its accessibility from a set of selected points of interests(POIs),which are defined as potential origin/destination points for transportation of *** shortest routes between each POI and potential zones are evaluated based on a cost function which can accommodate multiple criteria to determine the associated disutility for each potential ***,zones are ranked based on their cumulative disutility *** proposed analysis method is quantitative,and at the same time it is adequately flexible to allow inclusion of subjective *** of the proposed methodology is demonstrated for identifying optimal locations for a HAZMAT facility(e.g.,a nuclear facility)using the Canadian province of Saskatchewan as an *** scenarios were evaluated including(1)all network segments and POIs were treated equally,(2)network segments were rank ordered based on their functional classification while POIs were treated equally and(3)network segments were rank ordered based on their functional classification with preferences given to specific POI(s).

关键词： HAZMAT transportation Site selection Route planning Shortest path analysis

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Analysis and modeling of highway truck traffic volume variations during severe winter weather conditions in Canada

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Journal of Modern Transportation 2015年第3期23卷 228-239页

作者： Hyuk-Jae Roh satish sharma Prasanta K.Sahu Sandeep Datia City of Regina Faculty of Engineering and Applied Science University of Regina Department of Civil Engineering Birla Institute of Technology Pilani City of Edmonton

This paper investigates the impact of cold and snow on daily and hourly truck traffic volume on a primary highway in Alberta, Canada. This research is based on a detailed case study of 5 years of weigh-in-motion data recorded continuously at Leduc site on Highway 2A. Influence of the winter conditions on truck type distribution is examined by classifying trucks into single-unit trucks, single-trailer, and multi-trailer units. It is evident from the study that proportion of the three truck classes in the total truck traffic remained essentially stable over the study period （2005-2009）. Dummy-variable regression models are used to relate daily and hourly truck traffic volume with snowfall and categorized cold as independent variables. The statistical significance of all the independent variables used in the model is established by conducting tests such as R2, F test, incremental F test, and t test. The study results suggested that the truck volume is not significantly affected by the normal snowfall or the typical cold temperatures, i.e., average daily snowfall about less than 15 cm or temperatures higher than -25 ℃ are not likely to affect the truck traffic patterns. It is believed that the findings of this study can benefit highway agencies in developing programs and policies for efficient monitoring of truck traffic throughout the year and snow removal during the winter season in Canada.

关键词： Truck traffic ·Snowfall · Cold temperature ·Weather·Alberta· Canada

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Investigation of the factors affecting the consistency of short-period traffic counts

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Journal of Modern Transportation 2017年第3期25卷 150-162页

作者： Solomon Yadessa Kenno Prasanta K.Sahu Babak Mehran satish sharma Saskatchewan Ministry of Highways and Infrastructure Department of Civil Engineering Birla Institute of Technology and Science Pilani(BITS Pilani) Faculty of Engineering and Applied Science University of Regina

The main intent of this study is to investigate the accuracy of short-duration traffic counts conducted during winter months. The investigation is based on 11-year sample data collected using permanent traffic counters at various locations in Alberta, Canada. Four types of road sites： commuter, regional commuter, rural long-distance, and recreational sites are studied. The sample data consti- tute six different durations of counts （12-, 24-, 48-, 72-, 96-h, and 1 week） taken during summer and winter months. The coefficient of variation （CV） is used as the relative measure of deviation for counts of different dura- tions to measure the accuracy of short-period traffic counts. The study results indicate that 48-h count seems to be the most cost-effective counting interval during both summer and winter months. It is also found that the lowest values of CV result for counts taken at commuter sites, and the highest values are observed for recreational sites. Frequent changes in temperature and other weather events cause significant variation in traffic volume, which results in an increase in CV values for counts taken during winter months. The application of an adjustment factor to remove the effect of cold and snow from short-period counts is also included in this study. Introduced adjustment factors can reduce the values of CV for all counts taken during winter months. The findings of this study can lead highway agencies to improve the cost-effectiveness of their short- period traffic counting programs.

关键词： Short-period traffic counts Average annualdaily traffic - Design hourly volume

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Relative efficiency appraisal of discrete choice modeling algorithms using small-scale maximum likelihood estimator through empirically tailored computing environment

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Journal of Modern Transportation 2015年第1期23卷 67-79页

作者： Hyuk-Jae Roh Prasanta K. Sahu Ata M. Khan satish sharma City of Regina Regina SK S4P 3C8 Canada National Institute of Construction Management and Research Pune 411045 India Department of Civil and Environmental Engineering CarletonUniversity Ottawa ON K1S 5B6 Canada Environmental Systems Engineering University of ReginaRegina SK S4S 0A2 Canada

Discrete choice models are widely used in multiple sectors such as transportation, health, energy, and marketing, etc., where the model estimation is usually carried out by using commercial software. Nonetheless, tailored computer codes offer modellers greater flexibility and control of unique modelling situation. Aligned with empirically tailored computing environment, this research discusses the relative performance of six different algorithms of a discrete choice model using three key performance measures： convergence time, number of iterations, and iteration time. The computer codes are developed by using Visual Basic Application （VBA）. Maximum likelihood function （MLF） is formulated and the mathematical relationships of gradient and Hessian matrix are analytically derived to carry out the estimation process. The estimated parameter values clearly suggest that convergence criterion and initial guessing of parameters are the two critical factors in determining the overall estimation performance of a custom-built discrete choice model.

关键词： Estimation algorithms - Visual basicapplication Convergence criterion Binary logitMaximum likelihood

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Effect of Snow, Temperature and Their Interaction on Highway Truck Traffic

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Journal of Transportation Technologies 2013年第1期3卷 24-38页

作者： Hyuk-Jae Roh Sandeep Datla satish sharma City of Edmonton Edmonton Canada Faculty of Engineering University of Regina Regina Canada Saskatchewan Ministry of Highways and Infrastructure Regina Canada

Based on statistical amount of traffic and weather data sets from three weigh-in-motion sites for the study period of from 2005 to 2009, permanent traffic counters and weather stations in Alberta, Canada, an investigation is carried out to study impacts of winter weather on volume of passenger car and truck traffic. Multiple regression models are developed to relate truck and passenger car traffic variations to winter weather conditions. Statistical validity of study results are confirmed by using statistical tests of significance. Considerable reductions in passenger car and truck volumes can be expected with decrease in cold temperatures. Such reductions are higher for passenger cars as compared to trucks. Due to cold and snow interactions, the reduction in car and truck traffic volume due to cold temperature could intensify with a rise in the amount of snowfall. For passenger cars, weekends experience higher traffic reductions as compared to weekdays. However, the impact of weather on truck traffic is generally similar for weekdays and weekends. Interestingly, an increase in truck traffic during severe weather conditions is noticed at one of the study sites. Such phenomenon is found statistically significant. None of the past studies in the literature have presented the possibility of traffic volume increases on highways during adverse weather conditions;which could happen due to shift of traffic from parallel roads with inadequate winter maintenance programs. It is believed that the findings of this study can benefit highway agencies in developing such programs and policies as efficient monitoring of passenger car and truck traffic, and plan for efficient winter roadway maintenance programs.

关键词： Highway Truck Traffic Weigh-In-Motion Traffic-Weather Models Highway Design Vehicle Classification Highway Operations Traffic Volume Studies Transportation Statistics

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Association of periodontal disease with glycemic control in patients with type 2 diabetes in Indian population

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Frontiers of Medicine 2017年第1期11卷 110-119页

作者： Palka Kaur Khanuja satish Chander Narula Rajesh Rajputt Rajinder Kumar sharma Shikha Tewari Department of Periodontics and Oral Implantology PGIDS Post Graduate Institute of Dental Sciences Rohtak Haryana 124001 India Department of Medicine Unit VII and Endocrinology PGIMS Post Graduate Institute of Medical Sciences Rohtak Haryana 124001 India

This study aims to investigate the link between glycated hemoglobin and diabetic complications with chronic periodontitis. A total of 207 patients with type 2 diabetes and chronic periodontitis （CP） were divided according to tertiles of mean PISA （periodontal inflamed surface area） scores as low, middle and high PISA groups. Simultaneously a group of 67 periodontally healthy individuals （PH） was recruited. Periodontal examinations, including full-mouth assessment of probing depths （PPD）, bleeding on probing, clinical attachment level and plaque scores were determined. Blood analyses were carried out for glycated hemoglobin （HbA1c）, fasting plasma glucose （FPG）, 2 h post parandial glucose （PPG）. Individuals in PH group had significantly better glycemic control than CP group. Upon one-way analysis of variance, subjects with increased PISA had significantly higher HbA1c levels, retinopathy and nephropathy （P 〈 0.05）. After controlling for age, gender, body mass index （BMI）, socioeconomic status （SES）, family history of diabetes and periodontitis, duration of diabetes, the mean PISA in mm^2, PPD 4-6 mm （%） and PPD ≥7 mm （%） emerged as significant predictors for elevated HbAlc in regression model （P 〈 0.05）. Logistic regression analysis revealed that PISA was associated with higher risk of having retinopathy and neuropathy （odds ratio）. In our study, the association between glycemic control and diabetic complications with periodontitis was observed.

关键词： type 2 diabetes mellitus hemoglobin A glycated chronic periodontitis

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