Browsing by Author "Rono, Nicholas"
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Publication Characterization of Forest Fire Emissions and Their Possible Toxicological Impacts on Human Health(Institute of Forest Science, kangwon National University, 2017-05-31) Kibet, Joshua; Bosire, Josephate; Kinyanjui, Thomas; Lang'at, Moses; Rono, NicholasIn flight particulate matter particularly emissions generated by incomplete combustion processes has become a subject of global concern due to the health problems and environmental impacts associated with them. This has compelled most countries to set standards for coarse and fine particles due to their conspicuous impacts on environment and public health. This contribution therefore explores forest fire emissions and how its particulates affects air quality, damage to vegetation, water bodies and biological functions as architects for lung diseases and other degenerative illnesses such as oxidative stress and aging. Soot was collected from simulated forest fire using a clean glass surface and carefully transferred into amber vials for analysis. Volatile components of soot were collected over 10 mL dichloromethane and analyzed using a QTOF Premier-Water Corp Liquid Chromatography hyphenated to a mass selective detector (MSD), and Gas Chromatograph coupled to a mass spectrometer (GC-MS). To characterize the size and surface morphology of soot, a scanning electron microscope (SEM) was used. The characterization of molecular volatiles from simulated forest fire emissions revealed long chain compounds including octadec-9-enoic acid, octadec-6-enoic acid, cyclotetracosane, cyclotetradecane, and a few aromatic hydrocarbons (benzene and naphthalene). Special classes of organics (dibenzo-p-dioxin and 2H-benzopyran) were also detected as minor products. Dibenzo-p-dioxin for instance in chlorinated form is one of the deadliest environmental organic toxins. The average particulate size of emissions using SEM was found to be $11.51{\pm}4.91{\mu}m$. This study has shown that most of the emissions from simulated forest fire fall within $PM_{10}$ particulate size. The molecular by-products of forest fire and particulate emissions may be toxic to both human and natural ecosystems, and are possible precursors for various respiratory ailments and cancers. The burning of a forest by natural disasters or man-made fires results in the destruction of natural habitats and serious air pollution.Publication Optimization of Hole Transport Layer Materials for a Lead-Free Perovskite Solar Cell Based on Formamidinium Tin Iodide(Energy Technology, 2021-10-31) Rono, Nicholas; Merad, Abdelkrim E.; Kibet, Joshua K.; Martincigh, Bice S.; Nyamori, Vincent O.Recently, lead-based perovskite solar cells have been mainly studied; however, these cells suffer from two main problems: the toxicity of lead and the instability of the devices, which limit their commercialization. Herein, a theoretical investigation of a lead-free perovskite solar cell based on formamidinium tin iodide (HC(NH2)2SnI3) with the general architecture: glass/FTO/WS2/HC(NH2)2SnI3/HTL/Au is reported. All calculations are performed with the SCAPS-1D solar cell simulator. Two inorganic (CuSCN and Cu2O) and two organic (P3HT and D-PBTTT-14) hole transport layer (HTL) materials are tested in this model. The effect of the external operating temperature and different metal work functions of the back contact of the cell on the overall performance of the devices is also studied. Simulations showed that, with the introduction of CuSCN, Cu2O, and P3HT as HTLs, the device can attain a remarkable efficiency of ≈21%. All the modeled devices showed remarkable performance of above 20% at higher temperatures of 380–420 K but degraded slightly when this range is exceeded. Relatively cheaper Pt, Ni, and Pd metals perform better, thus, can replace gold. These simulation results can provide avenues and directions for future advancement of the performance of lead-free perovskite solar cells.