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Levels of Lead (Pb), Cadmium (Cd) and Cobalt (Co) in Cow Milk from Selected Areas of Zanzibar Island, Tanzania

American Journal of Analytical Chemistry 2023年第7期14卷 287-304页

作者： hassan rashid ali Mwanahija Mohamed Ame Mohammed ali Sheikh Said Suleiman Bakari School of Natural and Social Sciences The State University of Zanzibar Zanzibar Tanzania Tropical Research Centre for Oceanography Environment and Natural Resources The State University of Zanzibar Zanzibar Tanzania

Milk is one of the very important nutrients of human diet. The presence of toxic elements in milk may threaten the public health. This study reports the levels of Cadmium (Cd), Cobalt (Co) and Lead (Pb) in raw cow’s milk collected from different areas of Zanzibar Island during March - May 2016. The samples of raw milk were analyzed by Thermo Scientific-Atomic Absorption Spectrophotometer for quantitative determination of the metals in the matrix. The concentration of Co in this study ranged from ND at Mwanakwerekwe (MK1 and MK2) to a maximum of 0.004 mg/L at Mshelishelini (MS5) and Fuoni (F5) sites with mean concentration of 0.020 ± 0.003 mg/L for all sites. Concentration of Pb ranged between 0.05 - 0.51 mg/L at Fuoni (F7) and Mwanakwerekwe (MK1) respectively, with mean concentration of 0.263 ± 0.031 mg/L for all sites. However, Cd was only detected in one sample collected at Fuoni (F3) with a concentration of 0.001 mg/L. The results revealed that cow’s milk is contaminated with toxic metals, particularly Pb which exceeded the WHO maximum permissible level of 0.02 mg/L. The study furthermore sheds light on possible consequences to public health. It is recommended that, stakeholders especially in Zanzibar such as Zanzibar Food and Drug Authorities (ZFDA) and Zanzibar Bureau of Standards (ZBS) as well as researchers, use the findings of this study for policy making, future study plans, formulation of technical strategies to control milk contamination, risk assessment and develop new alternative methods to measure milk contamination even at a low detection limit for the sake of the consumers’ welfare before posing any serious effects to their health.

关键词： Milk Cobalt Lead Cadmium Zanzibar

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Levels and Distribution of Polycyclic Aromatic Hydrocarbons (PAHs) in Marine Sediments of Eastern Bank Wesha Peninsular, Pemba Island, Tanzania

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Journal of Environmental Protection 2023年第7期14卷 493-506页

作者： hassan rashid ali Seif Hamad Khalfan Haji Mwevura Haji Said Suleiman Bakari School of Natural and Social Sciences The State University of Zanzibar Zanzibar Tanzania Tropical Research Centre for Oceanography Environment and Natural Resources The State University of Zanzibar Zanzibar Tanzania

Levels of Polycyclic aromatic hydrocarbons (PAHs) from sediments collected in July 2017, a week after tanks oil leak in the bay of Wesha Peninsular, Pemba Island are reported. Four sampling points were chosen alongside the mangroves where a total of twenty samples were collected during the low tides. Eight PAHs were detected with concentrations ranging from ND to 53.42 ng/g (dw). Total PAHs in sediments was 158.38 ng⋅g-1. Phenanthrene residues (lower molecular weight) were dominant followed by pyrene (higher molecular weight PAHs) accounting for 90% and 40% detection frequencies, respectively. Statistical analysis showed no significant difference in the concentrations of PAHs among sites (p < 0.05, ANOVA). Vertical distribution of PAHs shows no definite patterns with sediment depth, however, composition patterns of PAHs along sediment depth indicate that higher molecular weight PAHs tend to remain in middle layer (2 - 4 cm). The results advocate the needs of proper monitoring to avoid the possible consequences to the public health.

关键词： PAHs POPs Sediments Marine Pollution Wesha

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The Influence of Climate Change and Variability on Aircraft Take-off and Landing Performance;a Case Study of the Abeid Amani Karume International Airport-Zanzibar

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Journal of Transportation Technologies 2022年第3期12卷 453-474页

作者： Omar Mohamed Haji Kombo Hamad Kai Sara Abdalla Khamis Said Suleiman Bakar hassan rashid ali Gharib Hamza Mohamed Fatma Said Seif Tanzania Civil Aviation Authority Zanzibar Office Kisauni Zanzibar Tanzania Meteorological Authority Zanzibar Office Kisauni Zanzibar State University of Zanzibar Tunguu Zanzibar

Climate change (CC) and variability have been world widely reported to pose number of risks in aviation industry including accidents, astray, and other operational difficulties. The impact of weather on landing and take-off performances has been several times experienced at Abeid Amani Karume International Airport (AAKIA);however, the influence of climate change and variability to the aircraft performance needs to be assessed. Thus, this study investigated the influence of climate change and variability on aircrafts take-off and landing performances. Specifically, the study investigated;i) the influence of climate change on Take-off Distance Required (TODR) and Maximum Take-off Mass (MTOM) for different types of aircraft;ii) the influence of climate variability to the aircraft landing performance on light, medium and heavy aircraft and lastly, iii) the study investigated the seasonal and annual variability on aircraft landing performance due to climate variability. The datasets used in this study include the eight years (2014-2021), aircraft operational records (diversion and missed approach events) and Aviation Routine Weather Reports (METAR) records which were utilized as the indicators for landing performance, the long-term (1990-2020) annual maximum temperatures (Tmax) which was used to determine the TODR and MTOM. Statistical tools including mean, percentage changes, correlations, regression, and the chi-square test were used for analysis and hypotheses testing. The results revealed that light and medium aircraft categories were significantly most affected on diversion events as compared to the heavy categories;however, for the missed approach events the impact was vice versa. Moreover, the seasonal and annual variability on diversion and missed approach events were significantly different (at p ≤ 0.001). As for the take-off performance, results show that the TODR and MTOM were significantly increasing and decreasing (at p ≤ 0.001), based on increasing air temp

关键词： Aircraft Take off/Landing Performance Missed Approach Diversion Take off Distance Required Maximum Take-off Mass Diversion Missed Approach

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Internet of Things Cloud Framework for Smart Homes

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Journal of Electronic Science and Technology 2016年第4期14卷 319-327页

作者： RaafatAburukba A.R.Al-ali Mohammed rashid Rizwan hassan Department of Computer Science and Engineering American University of SharjahSharjahUAE

Smart appliances and renewable energy resources are becoming an integral part of smart homes. Nowadays, home appliances are communicating with each other with home short-range home area gateways, using existing network communication protocols such as ZigBee, Bluetooth, RFID, and WiFi. A Gateway allows homeowners and utilities to communicate remotely with the appliances via long-range communication networks such as GPRS, WiMax, LTE, and power liner carrier. This paper utilizes the Internet of Things （IoT） concepts to monitor and control home appliances. Moreover, this paper proposes a framework that enables the integration and the coordination of Human-to-Appliance, Utility-to- Appliance, and Appliance-to-Appliance. Utilizing the concepts of Internet of Things leads to one standard communication protocols, TCP/IPV6, which overcomes the many diverse home area networks and neighborhood area networks protocols. This work proposes a cloud based framework that enables the IoTs integration and supports the coordination between devices, as well as with device-human interaction. A prototype is designed, implemented, and tested to validate the proposed solution.

关键词： Internet of things (IoT) Internet of things (IoT) cloud framework smart homes smart appliances.

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Wave propagation in parallel-plate waveguides filled with nonlinear left-handed material

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Chinese Physics B 2011年第1期20卷 346-351页

作者： Burhan Zamir rashid ali Department of Physics University of the PunjabQuaid-i-Azam CampusLahore-54590Pakistan

A theoretical investigation of field components for transverse electric mode in the parallel-plate waveguides has been studied. In this analysis two different types of waveguide structures have been discussed, i.e., （a） normal good/perfect conducting parallel-plate waveguide filled with nonlinear left-handed material and （b） high-temperature-superconducting parallel-plate waveguide filled with nonlinear left-handed material. The dispersion relations of transverse electric mode have also been discussed for these two types of waveguide structures.

关键词： waveguides wave propagation left-handed materials

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Forest Cover Change Assessment in Conflict-affected Areas of Northwest Pakistan: the Case of Swat and Shangla Districts

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Journal of Mountain Science 2012年第3期9卷 297-306页

作者： Faisal Mueen QAMER Sawaid ABBAS rashid SALEEM Khurram SHEHZAD hassan ali Hammad GILANI World Wide Fund for Nature(WWF)Pakistan LahorePakistan International Centre for Integrated Mountain Development(ICIMOD) KathmanduNepal Asian Institute of Technology BangkokThailand

This study examines the spatial and temporal forest cover changes in Swat and Shangla districts to understand the deforestation pattern in context of the recent security conflict in these districts. We used multi-resolution satellite images to assess the long term deforestation from 2001 to 2009 and also to identify episodic forest cutting areas appeared during the conflict period of Oct. 2007 - Oct. 2008. There are only 58 ha of deforestation identified during the conflict period while 1268 ha of gross annual deforestation were assessed during last eight years. Most of the deforestation patches persist around the administrative boundaries at sub-district levels (tehsils) which can be attributed to ambiguity in unclear jurisdiction between the forest official. The results highlight that the forest cutting appeared in Swat and Shangla during the conflict period is not as significant when compared with the long term deforestation pattern in the area. On the one side the results of the study are supportive to the picture that emerges from international studies which report high rate of deforestation in the country and on the other side it negates any relation between the security situation and the increasing deforestation in the north western Pakistan. The study concludes that deforestation assessments require verification by independent sources of data, such as satellite imagery to improve our understanding of deforestation processes.

关键词： Forest cover change Deforestation Conflict-affected area GIS Pakistan

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Dielectric characteristic of dichlorodifluoromethane(R12)gas and mixture with N_(2)/air as an alternative to SF_(6)gas

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High Voltage 2017年第3期2卷 205-210页

作者： Rahmat Ullah Abdur rashid Arooj rashid Faisal Khan Amjad ali Department of Electrical Engineering CIIT AbbottabadPakistan

In this study,dichlorodifluoromethane(R12)gas and mixtures with nitrogen(N_(2))and air at different pressures and mixing ratios have been investigated and showed good alternative to SF_(6) gas in terms of high-voltage *** gases contain R12 gas,they offer good dielectric properties and possibility to be used in low-temperature *** effects and self-recoverability test have been *** strength under quasi-uniform field showed in the order of SF_(6)>R12>N_(2)>air in alternating current(AC),direct current(DC)and impulse was *** R12/N_(2)(80/20%)could reach over 0.90–0.95 times to that of SF_(6) gas at 50 lb/in^(2) at AC and R12/air(70/30%)gives 0.80–0.90 to SF_(6) gas.R12 gas presents brilliant *** optimal ratio to switch SF_(6) gas is R12/N_(2)(80/20%)and R12/air(70/30%)is based on the authors’experimental condition and setup.

关键词： characteristic mixture mixing

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Cache in fog computing design,concepts,contributions,and security issues in machine learning prospective

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Digital Communications and Networks 2023年第5期9卷 1033-1052页

作者： Muhammad ali Naeem Yousaf Bin Zikria rashid ali Usman Tariq Yahui Meng ali Kashif Bashir School of Science Guangdong University of Petrochemical TechnologyMaoming525000China Department of Information and Communication Engineering Yeungnam UniversityGyeongsan38541Republic of Korea Department of Information and Communication Technologies Universitat Pompeu FabraBarcelonaSpain College of Computer Engineering and Sciences Prince Sattam Bin Abdulaziz UniversityAl-Kharj11942Saudi Arabia Department of Computing and Mathematics Manchester Metropolitan UniversityManchesterUnited Kingdom Woxsen School of Business Woxsen UniversityHyderabadIndia Department of Computer Science and Mathematics Lebanese American UniversityBeirutLebanon

The massive growth of diversified smart devices and continuous data generation poses a challenge to communication *** deal with this problem,communication networks consider fog computing as one of promising technologies that can improve overall communication *** brings on-demand services proximate to the end devices and delivers the requested data in a short *** computing faces several issues such as latency,bandwidth,and link utilization due to limited resources and the high processing demands of end *** this end,fog caching plays an imperative role in addressing data dissemination *** study provides a comprehensive discussion of fog computing,Internet of Things(IoTs)and the critical issues related to data security and dissemination in fog ***,we determine the fog-based caching schemes and contribute to deal with the existing issues of fog ***,this paper presents a number of caching schemes with their contributions,benefits,and challenges to overcome the problems and limitations of fog *** also identify machine learning-based approaches for cache security and management in fog computing,as well as several prospective future research directions in caching,fog computing,and machine learning.

关键词： Internet of things Cloud computing Fog computing Caching Latency

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Effects of sphere size on the microstructure and mechanical properties of ductile iron–steel hollow sphere syntactic foams

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International Journal of Minerals,Metallurgy and Materials 2016年第6期23卷 676-682页

作者： Hamid Sazegaran ali-Reza Kiani-rashid Jalil Vahdati Khaki Department of Metallurgical and Materials Engineering Faculty of Engineering Ferdowsi University of Mashhad

The effects of sphere size on the microstructural and mechanical properties of ductile iron–steel hollow sphere（DI–SHS） syntactic foams were investigated in this study. The SHSs were manufactured by fluidized-bed coating via the Fe-based commercial powder–binder suspension onto expanded polystyrene spheres（EPSs）. Afterwards, the DI–SHS syntactic foams were produced via a sand-mold casting process. The microstructures of specimens were investigated by optical microscopy, scanning electron microscopy（SEM）, and energy-dispersive X-ray spectroscopy（EDS）. The microscopic evaluations of specimens reveal distinct regions composed of the DI matrix, SHS shells, and compatible interface. As a result, the microstructures and graphite morphologies of the DI matrix depend on sphere size. When the sphere size decreases, the area fractions of cementite and graphite phases are observed to increase and decrease, respectively. Compression tests were subsequently conducted at ambient temperature on the DI–SHS syntactic foams. The results reveal that the compression behavior of the syntactic foams is enhanced with increasing sphere size. Furthermore, the compressed specimens demonstrate that microcracks start and grow from the interface region.

关键词： ductile iron steel syntactic foams microstructure mechanical properties

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Effects of copper content on the shell characteristics of hollow steel spheres manufactured using an advanced powder metallurgy technique

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International Journal of Minerals,Metallurgy and Materials 2016年第4期23卷 434-441页

作者： Hamid Sazegaran ali-Reza Kiani-rashid Jalil Vahdati Khaki Department of Materials Science and Metallurgical Engineering Engineering Faculty Ferdowsi University of Mashhad

Metallic hollow spheres are used as base materials in the manufacture of hollow sphere structures and metallic foams. In this study, steel hollow spheres were successfully manufactured using an advanced powder metallurgy technique. The spheres＇ shells were characterized by optical microscopy in conjunction with microstructural image analysis software, scanning electron microscopy（SEM）, energy-dispersive X-ray spectroscopy（EDX）, and X-ray diffraction（XRD）. The microscopic evaluations revealed that the shells consist of sintered iron powder, sintered copper powder, sodium silicate, and porosity regions. In addition, the effects of copper content on various parameters such as shell defects, microcracks, thickness, and porosities were investigated. The results indicated that increasing the copper content results in decreases in the surface fraction of shell porosities and the number of microcracks and an increase in shell thickness.

关键词： steel hollow spheres powder metallurgy copper content shell characteristics

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