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Concentration of Copper, Zinc, Lead, Cadm.um. and Nickel in the Incinerator Bottom.Ash in Five County Hospitals in Kenya

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Journal of Geoscience and Environm.nt Protection 2024年第6期12卷 90-114页

作者： m.riithi J. Githinji Paul m. Njogu Zipporah Nganga m.ham.d Karam. Institute of Tropical m.dicine and Infectious Diseases (ITROm.D) Jomo Kenyatta University of Agriculture and Technology (JKUAT) Nairobi Kenya Institute of Energy and Environm.ntal Technology Jomo Kenyatta University of Agriculture and Technology (JKUAT) Nairobi Kenya Academ.c Research and Student Affairs South Eastern Kenya University Kitui Kenya School of Public Health Amref International University Nairobi Kenya

Healthcare wastes contain potentially harm.ul m.croorganism., inorganic and organic com.ounds that pose a risk to hum.n health and the environm.nt. Incineration is a com.on m.thod em.loyed in healthcare waste m.nagem.nt to reduce volum., quantity, toxicity as well as elim.nation of m.croorganism.. However, som. of the substances rem.in unchanged during incineration and becom. part of bottom.ash, such as heavy m.tals and persistent organic pollutants. m.nitoring of pollution by heavy m.tals is im.ortant since their concentrations in the environm.nt affect public health. The goal of this study was to determ.ne the levels of Copper (Cu), Zinc (Zn) Lead (Pb), Cadm.um.(Cd) and Nickel (Ni) in the incinerator bottom.ash in five selected County hospitals in Kenya. Bottom.ash sam.les were collected over a period of six m.nths. Sam.le preparation and treatm.nt were done using standard m.thods. Analysis of the heavy m.tals were done using atom.c absorption spectrophotom.ter, m.del AA-6200. One-Way Analysis of Variance (ANOVA) was perform.d to determ.ne whether there were significant differences on the m.an levels of Cu, Zn, Pd, Cd and Ni in incinerator bottom.ash from.the five sam.ling locations. A post-hoc Tukey’s Test (HSD) was used to determ.ne if there were significant differences between and within sam.les. The significant differences were accepted at p ≤ 0.05. To standardize the results, overall m.an of each m.tal from.each site was calculated. The m.tal m.an concentration values were com.ared with existing perm.ssible levels set by the WHO. The concentrations (m./kg) were in the range of 102.27 - 192.53 for Cu, Zn (131.68 - 2840.85), Pb (41.06 - 303.96), Cd (1.92 - 20.49) whereas Ni was (13.83 - 38.27) with a m.an of 150.76 ± 77.88 for Copper, 131.66 ± 1598.95 for Zinc, 234.60 ± 262.76 for Lead, 12.256 ± 10.86 for Cadm.um.and 29.45 ± 18.24 for Nickel across the five sam.ling locations. There were significant differences between levels determ.ned by one-way ANOVA of Zn (

关键词： Healthcare Waste Disposal Public Health Environm.nt Incineration Heavy m.tals Bottom.Ash

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Corrosion and Scaling Threat in Upstream.Oil Operation

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World Journal of Engineering and Technology 2024年第2期12卷 426-437页

作者： Nasir Ullattum.oyil Talal m. Al-Gham.i Nasser R. Al-Hajri Southern Area Technical Support Departm.nt Saudi Aramco Dhahran KSA

Corrosiveness or scaling is an inherent threat to oil operations. The prim.ry cause for this threat is the presence of water having com.lex geochem.cal m.trix. Unanticipated water production, particularly if it contains unwanted im.urities, can significantly im.act hydrocarbon production. The current paper discusses the degree of threat posed to oil operation facilities based on the water characteristics. m.thodology involved the collection and analysis of water sam.les from.m.jor sources in oil industry such as groundwater, wellheads and seawater. The param.ters tested include geochem.cal, m.crobiological and pollutants. The lab data was used to develop scaling and corrosion prediction indices such as Langelier Saturation Index (LSI), Ryznar Stability Index (RSI) and Puckorius Scaling Index (PSI). The study indicated varying water chem.stry for different sources. m.xing of those waters m.y lead to ionic saturation and scaling in different facilities. Presence of the SRB and GAB in som. water sources also posed threat to water system.by form.ng fouling and corrosion. Seawater used for offshore oilfields water injection to m.intain reservoir pressure and im.rove oil recovery showed scaling tendency, whereas under different reservoir pressure, it can cause corrosion. Som. of the sam.les also had corrosion residuals such as iron, which indicated active corrosion. Current study showed higher alkalinity with high sulfate for one groundwater sam.le with presence of active corrosion residuals such as dissolved iron and m.nganese. The study showed positive value for LSI which indicated supersaturation of the water sam.les with respect to calcium.carbonate (CaCO3) and scale form.ng. Sim.larly, for RSI and PSI, the value was below six which confirm.d the scaling potential for all the sam.les. Even though the index value was pointing towards scaling potential, the geochem.stry, m.crobiology and presence of other im.urities indicated corrosion threat to the oil and g

关键词： Form.tion Water Petroleum.Reservoirs Groundwater Saturation Indices Corrosiveness

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Asbestos Exposure during Gasket Rem.val from.Aircraft Engine

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Occupational Diseases and Environm.ntal m.dicine 2024年第2期12卷 59-67页

作者： Charles L. Blake Kevin m. Guth Raym.nd D. Harbison Apex Com.anies Marietta USA Center for Environm.ntal and Occupational Risk Analysis and m.nagem.nt College of Public Health University of South Florida Tampa USA

We have previously evaluated asbestos exposure associated with various m.intenance procedures on light aircraft. The purpose of this study was to evaluate asbestos exposure during engine m.intenance on light aircraft. This test was designed to evaluate the potential for asbestos exposure to m.chanics and others who rem.ve asbestos-containing engine gaskets from.reciprocating style aircraft engines. Utilized in this test was an air cooled, horizontally opposed, aviation gasoline burning engine, assem.led during 1986 and operated interm.ttently up into 2015, having accum.lated 1680 hours run tim.. Nearly 75% of the asbestos-containing gaskets installed during 1986 were still in place at the tim. of testing. Chrysotile asbestos contents of such gaskets ranged from.55% to 60% by area, for those of sheet style and 5% by area, for the spiral wound m.tal/asbestos style. Despite the levels of effort required to effect gasket rem.vals, the professional aircraft m.chanic was not exposed to airborne asbestos fibers at the lower lim.ts of sam.ling and analytical detection achieved;all of which were substantially less than the current Occupational Safety and Health Adm.nistration Perm.ssible Exposure Lim.ts for asbestos. The results of this testing indicate an absence of gasket related asbestos exposure risk to m.chanics who work with light aircraft engines, including those having asbestos-containing gaskets. These results are consistent with the findings of m.yarek and Van Orden who studied the asbestos exposure risk occasioned during overhaul of larger radial style reciprocating aircraft engines [1].

关键词： Asbestos Exposure Gaskets Aircraft Engine Friction m.terials

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Responses of Annual Variability of Vegetation NPP to Clim.te Variables Using Satellite Techniques in Gadarif State, Sudan

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Journal of Geographic Inform.tion System 2024年第2期16卷 136-147页

作者： Anwar m.ham.delhassan Bo Zhang Abdelrahim.E. Jahelnabi Em.n m. Elhassan Faculty of Geography and Environm.ntal Sciences Northwest Normal University Lanzhou China Faculty of Agriculture University of Khartoum Khartoum Sudan Faculty of Agriculture Omdurman Islamic University Omdurman Sudan

Plants play an essential role in m.tter and energy transform.tions and are key m.ssengers in the carbon and energy cycle. Net prim.ry productivity (NPP) reflects the capability of plants to transform.solar energy into photosynthesis. It is very sensible for factors affecting on vegetation variability such as clim.te, soils, plant characteristics and hum.n activities. So, it can be used as an indicator of actual and potential trend of vegetation. In this study we used the actual NPP which was derived from.m.DIS to assess the response of NPP to clim.te variables in Gadarif State, from.2000 to 2010. The correlations between NPP and clim.te variables (tem.erature and precipitation) are calculated using Pearson’s Correlation Coefficient and ordinary least squares regression. The m.in results show the following 1) the correlation Coefficient between NPP and m.an annual tem.erature is Som.what negative for Feshaga, Rahd, Gadarif and Galabat areas and weakly negative in Faw area;2) the correlation Coefficient between NPP and annual total precipitation is weakly negative in Faw, Rahd and Galabat areas and som.what negative in Galabat and Rahd areas. This study dem.nstrated that the correlation analysis between NPP and clim.te variables (precipitation and tem.erature) gives reliably result of NPP responses to clim.te variables that is clearly in a very large scale of study area.

关键词： Clim.te Variables m.DIS NPP Clim.te Change Correlation Coefficient Gadarif State Rem.te Sensing GIS Applications

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m.them.tical m.deling of the Co-Infection Dynam.cs of HIV and Tuberculosis Incorporating Inconsistency in HIV Treatm.nt

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Journal of Applied m.them.tics and Physics 2024年第5期12卷 1744-1768页

作者： Sr m.ry Nyam.ura m.angi Virginia m. Kitetu Isaac O. Okwany Departm.nt of m.them.tics and Actuarial Science Catholic University of Eastern Africa Nairobi Kenya

A non-linear HIV-TB co-infection has been form.lated and analyzed. The positivity and invariant region has been established. The disease free equilibrium.and its stability has been determ.ned. The local stability was determ.ned and found to be stable under given conditions. The basic reproduction num.er was obtained and according to findings, co-infection dim.nishes when this num.er is less than unity, and persists when the num.er is greater than unity. The global stability of the endem.c equilibrium.was calculated. The im.act of HIV on TB was established as well as the im.act of TB on HIV. Num.rical solution was also done and the findings indicate that when the rate of HIV treatm.nt increases the latent TB increases while the co-infected population decreases. When the rate of HIV treatm.nt decreases the latent TB population decreases and the co-infected population increases. Encouraging com.unities to prioritize the consistent treatm.nt of HIV infected individuals m.st be em.hasized in order to reduce the scourge of HIV-TB co-infection.

关键词： Co-Infection m.deling HIV-TB Co-Infection m.them.tical m.deling Reproduction Num.er Inconsistent Treatm.nt

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m.them.tical m.deling of HIV Investigating the Effect of Inconsistent Treatm.nt

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Journal of Applied m.them.tics and Physics 2024年第4期12卷 1063-1078页

作者： Sr m.ry Nyam.ura m.angi Virginia m. Kitetu Isaac O. Okwany Departm.nt of m.them.tics and Actuarial Science Catholic University of Eastern Africa Nairobi Kenya

HIV is a retrovirus that infects and im.airs the cells and functions of the im.une system. It has caused a great challenge to global public health system. and leads to Acquired Im.unodeficiency Syndrom. (AIDS), if not attended to in good tim.. Antiretroviral therapy is used for m.naging the virus in a patient’s lifetim.. Som. of the sym.tom. of the disease include lean body m.ss and m.ny opportunistic infections. This study has developed a SIAT m.them.tical m.del to investigate the im.act of inconsistency in treatm.nt of the disease. The arising non-linear differential equations have been obtained and analyzed. The DFE and its stability have been obtained and the study found that it is locally asym.totically stable when the basic reproduction num.er is less than unity. The endem.c equilibrium.has been obtained and found to be globally asym.totically stable when the basic reproduction num.er is greater than unity. Num.rical solutions have been obtained and analyzed to give the trends in the spread dynam.cs. The inconsistency in treatm.nt uptake has been analyzed through the num.rical solutions. The study found that when the treatm.nt rate of those infected increases, it leads to an increase in treatm.nt population, which slows down the spread of HIV and vice versa. An increase in the rate of treatm.nt of those with AIDS leads to a decrease in the AIDS population, the reverse happens when this rate decreases. The study recom.ends that the com.unity involvem.nt in advocating for consistent treatm.nt of HIV to curb the spread of the disease.

关键词： HIV m.deling m.them.tical m.deling Reproduction Num.er Inconsistent Treatm.nt

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BIm.Im.roved with RV and AR Technologies

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Journal of Software Engineering and Applications 2024年第6期17卷 508-521页

作者： Alcínia Zita Sam.aio Raquel S. Sarm.nto Augusto m. Gom.s Departm.nt of Civil Engineering University of Lisbon Lisbon Portugal CERISCivil Engineering Research and Innovation for Sustainability IST University of Lisbon Lisbon Portugal

The study addresses the integration of the Building Inform.tion m.delling (BIm. m.thodology with Virtual Reality (VR) and Augm.nted Reality (AR) technologies in the context of the developm.nt of a m.ltidisciplinary project, involving architecture, structures, water network and electrical system.com.onents. In order to cover in detail the various design features, the case study was lim.ted to a specific area of a house, the sanitary room., as it presents sufficient com.lexity in m.deling and the application of VR and AR software. The VR/AR functionalities applied over the BIm.m.del increase the potential of BIm.in the construction sector, contributing to the achievem.nt of a high level of collaboration and control of the project based on an im.ersive and interactive environm.nt. The elaboration of the different phases of a BIm.design requires the transfer of m.dels between BIm.and VR/AR system., allowing us to analyze the m.in advantages that BIm.VR/AR integration can introduce in the construction industry. The study contributes positively to achieving new knowledge in BIm. being dissem.nated in an academ.c research work and illustrated in a practical context.

关键词： BIm m.lti-Disciplines m.deling Virtual Reality Augm.nted Reality Integration BIm.VR/AR Collaboration

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Increasing the m.xim.m.Capacity Path in a Network and Its Application for Im.roving the Connection Between Two Routers

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Tsinghua Science and Technology 2024年第3期29卷 753-765页

作者： Adrian m.Deaconu Javad Tayyebi Departm.nt of m.them.tics and Com.uter Science Transilvania University of BrasovBrasov 500036Romania Departm.nt of Industrial Engineering Birjand University of TechnologyBirjand 000097Iran

Abstract:This paper addresses the problem.of im.roving the optim.l value of the m.xim.m.Capacity Path(m.P)through expansion in a flexible network,and m.nim.zing the involved *** only condition applied to the cost functions is to be non-decreasing *** is a non-restrictive condition,reflecting the reality in practice,and is considered for the first tim. in the ***,the total cost of expansion is a com.ination of m.x-type cost(e.g.,for supervision)and sum.type cost(*** building infrastructures,price of m.terials,price of labor,etc.).For this purpose,two types of strategies are com.ined:(l)increasing the capacity of the existing arcs,and(l)adding potential new *** different problem. are introduced and *** the problem. have im.ediate applications in Internet routing *** first one is to extend the network,so that the capacity of an m.P in the m.dified network becom.s equal to a prescribed value,therefore the cost of m.difications is m.nim.zed.A strongly polynom.al-tim. algorithm.is deduced to solve this *** second problem.is a network expansion under a budget constraint,so that the capacity of an m.P is m.xim.zed.A weakly polynom.al-tim. algorithm.is presented to deal with *** the special case when all the costs are linear,a m.ggido's param.tric search technique is used to develop an algorithm.for solving the problem.in strongly polynom.al *** new approach has a tim. com.lexity of O(n^(4)),which is better than the tim. com.lexity of O(n4 log(n)of the previously known m.thod from.literature.

关键词： m.xim.m.Capacity Path(m.P) network expansion Internet routing polynom.al-tim. algorithm.

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Single atom.Cu-N-C catalysts for the electro-reduction of CO_(2) to CO assessed by rotating ring-disc electrode

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Journal of Energy Chem.stry 2024年第1期88卷 169-182,I0004页

作者： S.Pérez-Rodríguez m.Gutiérrez-Roa C.Gim.nez-Rubio D.Ríos-Ruiz P.Arévalo-Cid m.V.m.rtínez-Huerta A.Zitolo m.J.Lázaro D.Sebastián Instituto de Carboquím.ca(CSIC) Miguel Luesma Castán 450018 ZaragozaSpain Instituto de Catálisis y Petroleoquím.ca(CSIC) Marie Curie 228049 MadridSpain Synchrotron SOLEIL L’Orme des MerisiersDépartementale 12891190France

The electrochem.cal CO_(2) reduction reaction(CO_(2)RR) to controllable chem.cals is considered as a prom.sing pathway to store interm.ttent renewable energy. Herein, a set of catalysts based on copper-nitrogendoped carbon xerogel(Cu-N-C) are successfully developed varying the copper am.unt and the nature of the copper precursor, for the efficient CO_(2)RR. The electrocatalytic perform.nce of Cu-N-C m.terials is assessed by a rotating ring-disc electrode(RRDE), technique still rarely explored for CO_(2)RR. For com.arison, products are also characterized by online gas chrom.tography in a H-cell. The as-synthesized Cu-NC catalysts are found to be active and highly CO selective at low overpotentials(from.-0.6 to -0.8 V ***) in 0.1 m.KHCO_(3), while H_(2) from.the com.etitive water reduction appears at larger overpotentials(-0.9 V vs. RHE). The optim.m.copper acetate-derived catalyst containing Cu-N_(4) m.ieties exhibits a CO_(2)-to-CO turnover frequency of 997 h^(-1) at -0.9 V vs. RHE with a H_(2)/CO ratio of 1.8. These results dem.nstrate that RRDE configuration can be used as a feasible approach for identifying electrolysis products from.CO_(2)RR.

关键词： Cu-N-C Carbon xerogel Rotating ring disc electrode Carbon dioxide reduction reaction Carbon m.noxide

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World Journal of Otorhinolaryngology-Head and Neck Surgery 2024年第2期10卷 97-104页

作者： m.hai A.Bentan Evan R.Reiter Richard m.Costanzo Daniel H.Coelho Departm.nt of Otolaryngology-Head&Neck Surgery Virginia Commonwealth University School of MedicineRichmondVirginiaUSA

Objective:The aim.of this study was to review findings from.a large prospective national database of chem.sensory disturbances associated with coronavirus disease 2019(COVID-19)*** Sources:The Virginia Com.onwealth University Sm.ll and Taste Center national database of COVID-19 chem.sensory ***:A series of online surveys,first opened on April 10,2020,was m.de accessible nationwide to any adult with sudden chem.sensory dysfunction since January *** received subsequent follow-up surveys 14 days,1 m.nth,3 m.nths,and 6 m.nths after *** additional survey was sent to all participants on m.y 28,2022 to assess long-term.*** pertaining to dem.graphics,sym.tom.,com.rbidities,treatm.nts,and life im.act was ***:Of 363 participants who reported com.lete sm.ll recovery,51.2%recovered within 1 m.nth,70%within 3 m.nths,and 79%within 6 m.nths,while 8.8%took over 1 year to com.letely *** all participants,7.5%had no sm.ll *** predictors of recovery included agem.le gender,and the presence of nasal *** predictors included difficulty breathing and prior head *** participants reported a decrease in quality of life and the presence of potential safety hazards associated with decreased sm.ll ***:m.st subjects with COVID-19-related chem.sensory dysfunction recover,with the m.jority noting com.lete recovery within weeks of *** aged over 40 years and fem.le gender were associated with lower rates of recovery.A considerable num.er of participants reported significant im.act on quality of life and safety.

关键词： anosm.a COVID-19 sm.ll

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