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11.
Usama Umer Jaber Abu Qudeiri Mohammad Ashfaq Abdulrahman AL-Ahmari 《浙江大学学报(A卷英文版)》2016,17(11):873-885
Chip morphology predictions in metal cutting have always been challenging because of the complexity of the various multiphysical phenomena that occur across the tool-chip interface. An accurate prediction of chip morphology is a key factor in the assessment of a particular machining operation with regard to both tool performance and workpiece quality. Although finite element (FE) models are being developed over the last two decades, their capabilities in modeling correct material flow around the tool tip with shear localization are very limited. FE models with an arbitrary Lagrangian Eulerian (ALE) approach are able to simulate correct material flow around the tool tip. However, these models are unable to predict any shear localization based on material flow criteria. On the other hand, FE models with a Lagrangian formulation can simulate shear localization in the chip segments; they need to make use of a mesh-based chip separation criterion that significantly affects material flow around the tool tip. In this study a mesh-free method viz. smoothed particles hydrodynamics (SPH) is implemented to simulate shear localization in the chip while machining hardened steel. Unlike other SPH models developed by some researchers, this model is based on a renormalized formulation that can consider frictional stresses along the tool-chip interface giving a realistic chip shape and material flow. SPH models with different cutting parameters are compared with the traditional FE models and it has been found that the SPH models are good for predicting shear localized chips and do not need any geometric or mesh-based chip separation criteria. 相似文献
12.
The effect of pressure on the hydrolysis rates and the degradation kinetics of environmentally persistent omethoate pesticide was studied. The results showed that the values of kobs increased and the values of activation volume (AV) decreased with increasing pressure. Among pH conditions (3.58, 6.01 and 8.5), pH 8.5 was found to be the unstable condition and its half-life was reduced from 263 min at 1 atm to 19.37 min at 10 atm. These results describe that high-pressure hydrolysis is a useful technique for the conversion of toxic organic phosphorus into inorganic phosphorus. 相似文献
13.
1 Ｉｎｔｒｏｄｕｃｔｉｏｎ Ｈｅａｖｙｍｅｔａｌｆｌｕｏｒｉｄｅｓｇｌａｓｓｅｓａｒｅｏｆｐｒｉｍａｒｙｉｎｔｅｒ ｅｓｔｆｏｒｉｍｐｏｒｔａｎｔａｐｐｌｉｃａｔｉｏｎｓｉｎｔｈｅｏｐｔｉｃａｌｃｏｍｍｕｎｉ ｃａｔｉｏｎｆｉｅｌｄ ,ｄｕｅｔｏｔｈｅｉｒｔｒａｎｓｐａｒｅｎｃｙｔｏｌｉｇｈｔｓｒａｎｇ ｉｎｇｆｒｏｍＵＶｔｏｉｎｆｒａｒｅｄｒｅｇｉｏｎｓ.Ｍｏｒｅｏｖｅｒ ,ｔｈｅｉｒｍｅ ｃｈａｎｉｃａｌｓｔｒｅｎｇｔｈｍａｋｅｓｔｈｅｍｇｏｏｄｃａｎｄｉｄａｔｅｓｆｏｒｗｉｎ ｄｏｗｓ,ｌａｓｅｒｈ… 相似文献
14.
Peter M. Fowler Darren J. Paul Gustavo Tomazoli Abdulaziz Farooq Richard Akenhead Lee Taylor 《European Journal of Sport Science》2017,17(9):1110-1118
The purpose was to assess sleep patterns, quantity and quality in adolescent (16.2?±?1.2 yr) Middle Eastern academy soccer players (n?=?20) and the influence of an intermission upon these characteristics. On a 17-day training camp (located one time zone west of home) including three discrete matches, sleep was assessed pre- (PRE) and post-match (POST) via wrist actigraphy. Retrospective actigraphy analysis identified sleep characteristics, including if players experienced a sleep intermission (YES) or not (NO) proximal to dawn, and bedtime (hh:mm), get-up time (hh:mm), time in bed (h), sleep duration (h) and sleep efficiency (%). Within YES two bouts were identified (BOUT1 and BOUT2). No differences were seen between PRE and POST, nor between BOUT1 and BOUT2 (p?>?.05). Overall players did not meet National Sleep Foundation (NSF) guidelines (7:04?±?1:16?h vs. recommended 8–10?h for 14–17 yr). Sleep duration was significantly reduced (～ ?13% or ?1:06) in YES compared to NO (6:33?±?1:05 vs. 7:29?±?1:17, p?<?.01). Despite players in YES waking earlier due to an intermission, they did not compensate for this with a later wake time, rising significantly earlier compared to NO (09:40?±?00:38 vs. 10:13?±?00:40, p?<?.05). These players on average do not obtain sufficient sleep durations relative to NSF guidelines, with decrements increased by an intermission proximal to dawn. High inter- and intra-individual variance in the players sleep characteristics indicates the need for individualized sleep education strategies and interventions to promote appropriate sleep. 相似文献
15.
M. Farooq Wahab 《Resonance》2009,14(10):996-1002
A functional monochromator model in a cardboard box, made from rotatable grating using a digital versatile disk is described
to highlight the working principles of a UV-Vis monochromator. The light source is a bright white LED and the colored bands
from the exit are displayed on the screen. The concept of absorption, complementary color, excitation and fluorescence, flame
emission spectrum, and wavelength dependence of light scattering can be visually shown in this model. With a minor modification,
one can use the same box to monitor flame emission spectrum of sodium and different light sources. As an optional activity,
the same properties are observed on a scanning spectrophotometer. 相似文献
16.
Farooq Sulehria 《亚洲交流杂志》2017,27(1):97-112
Mainstream discourses on the globalisation of media that delineate the emergence of privately owned television channels in the periphery country as evening out metropolitan domination are belied by concrete evidence. This essay argues that the rise of southern players has undermined state broadcasting rather than dismantling ‘media imperialism’. Based on two case studies, Pakistan Television (PTV) and Doordarshan (DD), this study demonstrates that the actual, if inadvertent, victim of globalisation has been state broadcasting and an associated developmentist model of television. As a result the decline of state-led television channels has radically transformed television systems in India and Pakistan. While DD and PTV view their audiences as citizens, the globalisation of media has resulted in a commodification of television audiences. Instead of public interest, audience maximisation has become the dominant logic of television systems in both these countries. In the process, developmentist television systems have been replaced by the commercially driven systems. 相似文献
17.
18.
Andrew Parker Haydn Morgan Samaya Farooq Ben Moreland Andy Pitchford 《Sport, Education and Society》2019,24(3):298-310
Numerous sport-based interventions exist which target marginalised or ‘at-risk’ young people with the intention of enabling some form of social change for programme participants. Very often, the objective of such interventions is the acquisition and development of qualities associated with ‘good citizenship’. However, critical scholars have noted how sport-based initiatives are frequently used as a form of social control, focusing on the development of personal responsibility. As such, these initiatives accentuate more passive forms of citizenship, as opposed to more active forms of citizenship towards which many educational policies and programmes are aimed. Nevertheless, there is a limited amount literature which explores the connection between sport-based interventions and citizenship development within marginalised or ‘at-risk’ youth populations. This paper presents findings from a small-scale, qualitative study of one such (football-based) intervention located in a number of inner-city boroughs of London, UK. Placing the accounts of programme participants and staff at the centre of the analysis, the paper: (i) uncovers the practicalities and nuances of football being utilised as a tool for social engagement, and (ii) explores broader notions of personal and behavioural development in relation to the acquisition of citizenship qualities. The paper concludes by suggesting that sporting activity may confer citizenship benefits for young people, but only when integrated into wider programmes of social support and community engagement. 相似文献
19.
Umer Farooq Craig H. GanoeJohn M. Carroll Isaac G. CouncillC. Lee Giles 《Information processing & management》2008
Awareness has been extensively studied in human computer interaction (HCI) and computer supported cooperative work (CSCW). The success of many collaborative systems hinges on effectively supporting awareness of different collaborators, their actions, and the process of creating shared work products. As digital libraries are increasingly becoming more than just repositories for information search and retrieval – essentially fostering collaboration among its community of users – awareness remains an unexplored research area in this domain. We are investigating awareness mechanisms in CiteSeer, a scholarly digital library for the computer and information science domain. CiteSeer users can be notified of new publication events (e.g., publication of a paper that cites one of their papers) using feeds as notification systems. We present three cumulative user studies – requirements elicitation, prototype evaluation, and naturalistic study – in the context of supporting CiteSeer feeds. Our results indicate that users prefer feeds that place target items in query-relevant contexts, and that preferred context varies with type of publication event. We found that users integrated feeds as part of their broader, everyday activities and used them as planning tools to collaborate with others. 相似文献
20.
Saira Hanif Soroya Ali Farooq Khalid Mahmood Jouni Isoaho Shan-e Zara 《Information processing & management》2021,58(2):102440
Individuals seek information for informed decision-making, and they consult a variety of information sources nowadays. However, studies show that information from multiple sources can lead to information overload, which then creates negative psychological and behavioral responses. Drawing on the Stimulus-Organism-Response (S-O-R) framework, we propose a model to understand the effect of information seeking, information sources, and information overload (Stimuli) on information anxiety (psychological organism), and consequent behavioral response, information avoidance during the global health crisis (COVID-19). The proposed model was tested using partial least square structural equation modeling (PLS-SEM) for which data were collected from 321 Finnish adults using an online survey. People found to seek information from traditional sources such as mass media, print media, and online sources such as official websites and websites of newspapers and forums. Social media and personal networks were not the preferred sources. On the other hand, among different information sources, social media exposure has a significant relationship with information overload as well as information anxiety. Besides, information overload also predicted information anxiety, which further resulted in information avoidance. 相似文献