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Impacts of environmental factors on urban heating

Journal of Environmental Sciences 2010年第12期22卷 1903-1909页

作者： rizwan Ahmed Memon Dennis Y.C.Leung Department of Mechanical Engineering Mehran University of Engineering & Technology Department of Mechanical Engineering The University of Hong Kong School of Energy and Environment City University of Hong Kong

This study investigated the impact of important environmental variables （i.e., wind speed, solar radiation and cloud cover） on urban heating. Meteorological parameters for fifteen years （from 1990 to 2005）, collected at a well developed and densely populated commercial area （Tsim Sha Tsui, Hong Kong）, were analyzed in details. Urban heat island intensity （UHII）, a well known indicator of urban heating, has been determined as the spatially averaged air-temperature difference between Tsim Sha Tsui and Ta Kwu Ling （a thinly populated rural area with lush vegetation）. Results showed that the UHII and cloud cover have increased by around 9.3% and 4%, respectively, whereas the wind speed and solar radiation have decreased by around 24% and 8.5%, respectively. The month of December experienced the highest UHII （10.2℃） but the lowest wind speed （2.6 m/sec） and cloud cover （3.8 oktas）. Conversely, the month of April observed the highest increases in the UHII （over 100%） and the highest decreases in wind speed （over 40 %） over fifteen years. Notably, the increases in the UHII and reductions in the wind speed were the highest during the night-time and early morning. Conversely, the intensity of solar radiation reduced while the intensity of urban cool island （UCII） increased during solar noon-time. Results demonstrated strong negative correlation between the UHII and wind speed （coefficient of determination, R^2 = 0.8） but no negative correlation between UCII and solar radiation attenuation. A possible negative correlation between UHII and cloud cover was investigated but could not be substantiated.

关键词： urban heat island urban cool island wind speed cloud cover

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Natural convection of CuO–water nanofluid filled in a partially heated corrugated cavity:KKL model approach

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Communications in Theoretical Physics 2020年第8期72卷 27-42页

作者： rizwan Ul Haq Muhammad Usman Ebrahem A Algehyne Department of Electrical Engineering Bahria UniversityIslamabadPakistan BIC-ESAT College of EngineeringPeking UniversityBeijing 100871China State Key Laboratory for Turbulence and Complex Systems Department of Mechanics and Engineering SciencePeking UniversityBeijing 100871China Department of Mathematics Faculty of SciencesUniversity of TabukP.O.Box 741Tabuk 71491Saudi Arabia

In this article, flow and heat transfer inside a corrugated cavity is analyzed for natural convection with a heated inner obstacle. Thermal performance is analyzed for Cu O–water inside a partially heated domain by defining the constraint along the boundaries. For nanofluid analysis, the Koo and Kleinstreuer Li(KKL) model is implemented to deal with the effective thermal conductivity and viscosity. A heated thin rod is placed inside the corrugated cavity and the bottom portion of the corrugated cavity is partially heated. The dimensionless form of nonlinear partial differential equations are obtained through the compatible transformation along with the boundary constraint. The finite element method is executed to acquire the numerical solution of the obtained dimensional system. Streamlines, isotherms and heat transfers are analyzed for the flow field and temperature distribution. The Nusselt number is calculated at the surface of the partially heated domain for various numerical values of emerging parameters by considering the inner obstacle at cold, adiabatic and heated conditions. The computational simulation was performed by introducing various numerical values of emerging parameters. Important and significant results have been attained for temperature and velocities(in both x-and y-directions) at the vertically and horizontally mean positions of the corrugated duct.

关键词： heat transfer nanofluid finite element method KKL corrugated cavity

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A unified approach of energy and data cooperation in energy harvesting WSNs

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Science China(Information Sciences) 2018年第8期61卷 170-182页

作者： Roomana YOUSAF rizwan AHMAD Waqas AHMED Fu-chun ZHENG School of Electrical Engineering and Computer Science National University of Sciences and Technology Department of Electrical Engineering Pakistan Institute of Engineering and Applied Sciences School of Electronic and Information Engineering Harbin Institute of Technology

Energy harvesting(EH) provisioned wireless sensor nodes are key enablers to increase network life time in modern wireless sensor networks(WSNs). However, the intermittent nature of the EH process necessitates management of nodes’ limited data and energy buffer capacity. In this paper, a unified mathematical model for a cooperative EHWSN with an opportunistic relay is presented. The energy and data causality constraints are expressed in terms of throughput, available energy, delay and transmission *** finite energy buffers, data buffers and discrete transmission rates(as defined in the standard IEEE 802.15.4) at the nodes, different intuitive online power allocation policies at the relay are *** results show that a policy achieving high throughput is less fair and vice versa. Therefore, a joint rate and power allocation policy(JRPAP) is proposed in this study which provides a better trade off between fairness, throughput and energy over intuitive policies. Based on the JRPAP results, we propose to use data aggregation(DA) to achieve throughput gain at lower buffer sizes. In addition, the notion of energy aggregation(EA) is introduced to achieve throughput gain at higher buffer sizes. Combining both EA and DA further improves the overall throughput at all buffer sizes.

关键词： energy harvesting energy causality data causality energy aggregation data aggregation opportunistic relay

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Saliency-based framework for facial expression recognition

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Frontiers of Computer Science 2019年第1期13卷 183-198页

作者： rizwan Ahmed KHAN Alexandre MEYER Hubert KONIK Saida BOUAKAZ Universite de Lyon CNRSLIRISUMR5205Universite Lyon 1Lyon F-69622France Faculty of Information Technology Barrett Hodgson UniversityKarachi 74900Pakistan Laboratoire Hubert Curien UMR5516Universite Jean MonnetSaint-Etienne 42000France

This article proposes a novel framework for the recognition of six universal facial *** framework is based on three sets of features extracted from a face image:entropy,brightness,and local binary ***, saliency maps are obtained using the state-of-the-art saliency detection algorithm "frequency-tuned salient region detection".The idea is to use saliency maps to determine appropriate weights or values for the extracted features (i.e.,brightness and entropy).We have performed a visual experiment to validate the performance of the saliency detection algorithm against the human visual *** movements of 15 subjects were recorded using an eye-tracker in free-viewing conditions while they watched a collection of 54 videos selected from the Cohn-Kanade facial expression *** results of the visual experiment demonstrated that the obtained saliency maps are consistent with the data on human ***,the performance of the proposed framework is demonstrated via satisfactory classification results achieved with the Cohn-Kanade database,FG-NET FEED database, and Dartmouth database of children's faces.

关键词： facial expression recognition classification salient regions entropy brightness local binary pattern

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Boron nitride-based electrocatalysts for HER,OER,and ORR:A mini-review

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Frontiers of Materials Science 2021年第4期15卷 543-552页

作者： Nabi ULLAH rizwan ULLAH Saraf KHAN Yuanguo XU School of Materials Science and Engineering Jiangsu UniversityZhenjiang 212013China School of Chemistry and Chemical Engineering Jiangsu UniversityZhenjiang 212013China National Centre of Excellence in Physical Chemistry University of PeshawarPeshawar25120Pakistan Institute of Chemical Sciences University of PeshawarKhyber Pakhtunkhwa25120Pakistan

A reliable and efficient solution to the current energy crisis and its associated environmental issues is provided by fuel cells,metal-air batteries and overall water *** heart reactions for these technologies are oxygen reduction reaction(ORR),oxygen evolution reaction(OER)and hydrogen evolution reaction(HER).Different supporters such as graphene,carbon nanotube,and graphitic carbon nitride have been used to avoid agglomeration of active materials and provide maximum active surface for these *** all the supporters,boron nitride(BN)gains extensive research attention due to its analogue with graphene and excellent stability with good oxidation and chemical *** this mini-review,the well-known strategies(exfoliation,annealing,and CVD)used in the synthesis of BN with different morphologies for HER,OER and ORR applications have been briefly debated and *** comparative analysis determines that the performance and stability of state-of-the-art electrocatalysts can be further boosted if they are deposited on *** is revealed that BN-based catalysts for HER,OER and ORR are rarely studied yet especially with non-noble transition metals,and this research direction should be studied deeply in future for practical applications.

关键词： boron nitride electrocatalyst hydrogen evolution reaction oxygen evolution reaction oxygen reduction reaction

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Electric-field induced fluctuations in laser generated plasma plume

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Plasma Science and Technology 2021年第4期23卷 83-89页

作者： rizwan AHMED Abdul JABBAR Zeshan Adeel UMAR Muhammad Aslam BAIG National Centre for Physics Quaid-i-Azam University Campus45320 IslamabadPakistan

The effect of an external electric field on laser-generated plasma has been *** is observed that the laser-generated plasma can be used for the ignition of a spark in the presence of a low voltage external electric *** eight-fold emission intensity enhancement in Cu I spectral lines are measured as compared to the signal intensity in the absence of an external electric *** plasma parameters remain the same initially,up to a few microseconds after the generation of plasma,and this feature makes it more interesting for the quantitative analysis of any sample using laser induced breakdown spectroscopy(LIBS).In the presence of an external electric field,fluctuations(contraction and expansion)in the laser-generated plasma are observed which increase the plasma decay time and consequently result in enhanced signal intensity.

关键词： LIBS laser produced plasma effect of external electric plasma parameters

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Comprehensive spectral analysis of Cyg X-1 using RXTE data

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Research in Astronomy and Astrophysics 2012年第10期12卷 1427-1438页

作者： rizwan Shahid Ranjeev Misra S.N.A.Jaaffrey Department of Physics M.L.Sukhadia UniversityUdaipur-313001India Inter University Centre for Astronomy and Astrophysics Pune-411007India

We analyze a large number （〉 500） of pointed Rossi X-Ray Timing Explorer （RXTE） observations of Cyg X- 1 and model the spectrum of each one. A subset of the observations for which there is a simultaneous reliable measure of the hardness ratio by the All Sky Monitor shows that the sample covers nearly all the spectral shapes of Cyg X-1. Each observation is fitted with a generic empirical model consisting of a disk black body spectrum, a Comptonized component whose input photon shape is the same as the disk emission, a Gaussian to represent the iron line and a reflection feature. The relative strength, width of the iron line and the reflection parameter are in general correlated with the high energy photon spectral index F. This is broadly consistent with a geometry where for the hard state （low F ~ 1.7） there is a hot in- ner Comptonizing region surrounded by a truncated cold disk. The inner edge of the disk moves inwards as the source becomes softer till finally in the soft state （high F 〉 2.2） the disk fills the inner region and active regions above the disk produce the Comptonized component. However, the reflection parameter shows non-monotonic behavior near the transition region （F ~ 2）, which suggests a more complex geometry or physical state of the reflector. In addition, the inner disk temperature, during the hard state, is on average higher than in the soft one, albeit with large scatter. These inconsistencies could be due to limitations in the data and the empirical model used to fit them. The flux of each spectral component is well correlated with F, which shows that unlike some other black hole systems, Cyg X- 1 does not show any hysteresis be- havior. In the soft state, the flux of the Comptonized component is always similar to the disk one, which confirms that the ultra-soft state （seen in other brighter black hole systems） is not exhibited by Cyg X-1. The rapid variation of the Compton amplifica- tion factor with F naturally explains the absence of spec

关键词： accretion accretion disks -- X-rays: binaries

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pH-triggered cancer-targeting polymers:From extracellular accumulation to intracellular release

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Nano Research 2023年第4期16卷 5155-5168页

作者： rizwan Ullah Khan Jinning Shao Jia-Yu Liao Linghui Qian Institute of Drug Metabolism and Pharmaceutical Analysis Zhejiang Province Key Laboratory of Anti-Cancer Drug ResearchCollege of Pharmaceutical SciencesCancer Center&Hangzhou Institute of Innovative MedicineZhejiang UniversityHangzhou 310058China

Stimuli-responsive polymers are promising to achieve targeted delivery,improved stability during circulation,and controlled release of therapeutic and diagnostic *** them,pH-responsive polymeric nanocarriers have attracted significant attention as pH varies in different body fluids(e.g.,stomach,intestine,and colon)and intracellular organelles(e.g.,endosome,lysosome,and mitochondria)to maintain homeostasis,while distinctive pH changes are also found in certain pathological *** example,the extracellular environment of the tumor is acidic,which can be employed to drive selective *** the internalization process,since most nanocarriers enter cells upon endocytosis where a drop of pH from 6.5 to 5.0 can occur from endosome to lysosome,pH-sensitive groups have been developed for enhanced cargo *** this review,both non-covalent and covalent interactions responsive to pH changes are introduced,with a focus on the structure-property relationship and their applications in cancer targeting and endosomal escape.

关键词： cancer targeting pH-responsive structure-property relationship charge shifting acid-labile linkage

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Smart CardioWatch System for Patients with Cardiovascular Diseases Who Live Alone

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Computers, Materials & Continua 2021年第2期66卷 1237-1250页

作者： Raisa Nazir Ahmed Kazi Manjur Kolhar Faiza rizwan College of Applied Medical Science Prince Sattam Bin Abdulaziz UniversityWadi Ad Dawaser11990Saudi Arabia Department Computer Science Prince Sattam Bin Abdulaziz UniversityWadi Ad Dawaser11990Saudi Arabia

The widespread use of smartwatches has increased their specific and complementary activities in the health sector for patient’s *** this study,we propose a framework referred to as smart forecasting CardioWatch(SCW)to measure the heart-rate variation(HRV)for patients with myocardial infarction(MI)who live alone or are outside their *** this study,HRV is used as a vital alarming sign for patients with *** performance of the proposed framework is measured using machine learning and deep learning techniques,namely,support vector machine,logistic regression,and decision-tree classification *** results indicated that the analysis of heart rate can help health services that are located remotely from the patient to render timely emergency health ***,taking more cardiac parameters into account can lead to more accurate *** the basis of our findings,we recommend the development of health-related software to aid researchers to develop frameworks,such as SCW,for effective provision of emergency health.

关键词： Forecasting system machine learning algorithms medical forecasting systems medical control systems supervised learning

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Artificial Intelligence-Based Semantic Segmentation of Ocular Regions for Biometrics and Healthcare Applications

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Computers, Materials & Continua 2021年第1期66卷 715-732页

作者： rizwan Ali Naqvi Dildar Hussain Woong-Kee Loh Department of Unmanned Vehicle Engineering Sejong UniversitySeoul05006Korea School of Computational Science Korea Institute for Advanced Study(KIAS)Seoul02455Korea Department of Software Gachon UniversitySeongnam13120Korea

Multiple ocular region segmentation plays an important role in different applications such as biometrics,liveness detection,healthcare,and gaze ***,segmentation techniques focus on a single region of the eye at a *** the number of obvious advantages,very limited research has focused on multiple regions of the ***,accurate segmentation of multiple eye regions is necessary in challenging scenarios involving blur,ghost effects low resolution,off-angles,and unusual ***,the available segmentation methods cannot address these *** this paper,to address the accurate segmentation of multiple eye regions in unconstrainted scenarios,a lightweight outer residual encoder-decoder network suitable for various sensor images is *** proposed method can determine the true boundaries of the eye regions from inferior-quality images using the high-frequency information flow from the outer residual encoder-decoder deep convolutional neural network(called ORED-Net).Moreover,the proposed ORED-Net model does not improve the performance based on the complexity,number of parameters or network *** proposed network is considerably lighter than previous state-of-theart *** experiments were performed,and optimal performance was achieved using SBVPI and UBIRIS.v2 datasets containing images of the eye *** simulation results obtained using the proposed OREDNet,with the mean intersection over union score(mIoU)of 89.25 and 85.12 on the challenging SBVPI and UBIRIS.v2 datasets,respectively.

关键词： Semantic segmentation ocular regions biometric for healthcare sensors deep learning

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