Investigation of Properties of Concrete Using Sawdust as Partial Replacement for Sand

The concrete mix ratio of 1:2:4. was prepared using water/cement of 0.65 with  0%, 25%, 50%, 75% and 100% sawdust as partial replacement for fine sand. The coefficient of uniformity   and coefficient of curvature of the sand used in this study was 1.049 and 1.324 respectively which shows that the sand is a well graded sand as it does not exceed  the range of  1 and 3 for ; and  maximum of 6 for specified by the British standard. The aggregate crushing value (ACV) obtained is 43.75 which is within the specified value of 45 as specified by the British standard (BS 812-110 1992). However, values of 40mm, 9mm and 5mm respectively was obtained for workability at 0%, 25% and 50% addition of sawdust as partial replacement for sand, while 14.15 N/mm2, 12.96 N/mm2 and 11.93 N/mm2, were obtained for compressive strength with 25%, 75% and 100% sawdust as partial replacement. The Compressive strength values obtained were found not to conform to the minimum requirement of 17N/mm2 for light weight concrete. Using sawdust in a proportion greater than 25% replacement of sand is however detrimental to strength and density properties of concrete. Keywords: Sawdust, Concrete, Workability, Aggregate Crushing value, Compressive strength

Performance of coconut shell ash and palm kernel shell ash as partial replacement for cement in concrete

High cost of cement used as binder in the production of concrete has led to a search for alternative. Using a mix design ratio of 1:2:4 and water binder ratio of 0.63, concrete cubes were casted using varying ordinary Portland cement (OPC): palm kernel shell ash (PKSA) and ordinary Portland cement (OPC): coconut shell ash (CSA) ratios of 100:0, 90:10, 80:20, 70:30 , 60:40 and 50:50 respectively. This research reveal that partial replacement of cement with 20% PKSA and CSA in concrete gives an average optimum compressive strength of 15.4 N/mm2 and 17.26 N/mm2 respectively at 28 days. While, the optimum value of compressive strength obtained at 28 days is 20.58 N/mm2 at 10% replacement with CSA. The value obtained is suitable for both light weight and heavy weight concrete respectively. Thus, the research show that the use of PKSA and CSA as a partial replacement for cement in concrete, at lower volume of replacement, will enhance the reduction of cement usage in concretes, thereby reducing the production cost and the environmental pollution caused by the dumping of the agricultural waste

EFFECTS OF CO-TRIMOXAZOLE CO-ADMINISTRATION ON THE PHARMACOKINETICS OF AMODIAQUINE IN HEALTHY VOLUNTEERS

Objectives: Amodiaquine (AQ) is a 4-aminoquinoline antimalarial drug that is rapidly and extensively metabolized mainly by CYP2C8 enzyme to N-desethylamodiaquine (DEAQ). Co-trimoxazole (CTZ) is a combination (sulfamethoxazole and trimethoprim) antimicrobial agent with the trimethoprim component being a potent inhibitor of CYP2C8. AQ and CTZ are likely to be co-administered in the treatment of patients with malaria and susceptible bacterial infections. This study evaluates the effect of CTZ co-administration on the pharmacokinetics of AQ. Methods: In an open, two-way crossover study, 16 healthy volunteers were randomized to receive 600 mg single oral dose of AQ with or without the eleventh dose of CTZ (960 mg every 12 h for 7 days.) Blood samples were collected at pre-determined time intervals and analyzed for AQ and its major metabolite, DEAQ using a validated HPLC method.Results: Co-administration of AQ and CTZ resulted in significant increases in the total area under the concentration–time curve (AUCT), maximum plasma concentration (Cmax) and terminal elimination half-life (T½) of AQ compared with values with AQ dosing alone (AUCT:234.36±57.21 vs 366.42±62.48 h ng/ml; Cmax:24.86±7.28 vs 40.28±11.15 ng/ml; T½: 6.49±3.56 vs 9.24±2.97 h), while the oral plasma clearance markedly decreased (3862.66±756.38 vs 2654.28±650.12 L/h). Co-administration also led to a pronounced decrease in the ratio of AUC(metabolite)/AUC (unchanged drug) and highly significant decreases in Cmax and AUC of the metabolite.Conclusion: Study evaluated for the first time the effect of CTZ co-administration on the pharmacokinetics of AQ in healthy adult volunteers. CTZ significantly increased AQ exposure and decreased plasma levels of the active metabolite DEAQ.Â

Pathways for the Valorization of Animal and Human Waste to Biofuels, Sustainable Materials, and Value-Added Chemicals

Human and animal waste, including waste products originating from human or animal digestive systems, such as urine, feces, and animal manure, have constituted a nuisance to the environment. Inappropriate disposal and poor sanitation of human and animal waste often cause negative impacts on human health through contamination of the terrestrial environment, soil, and water bodies. Therefore, it is necessary to convert these wastes into useful resources to mitigate their adverse environmental effect. The present study provides an overview and research progress of different thermochemical and biological conversion pathways for the transformation of human- and animal-derived waste into valuable resources. The physicochemical properties of human and animal waste are meticulously discussed, as well as nutrient recovery strategies. In addition, a bibliometric analysis is provided to identify the trends in research and knowledge gaps. The results reveal that the USA, China, and England are the dominant countries in the research areas related to resource recovery from human or animal waste. In addition, researchers from the University of Illinois, the University of California Davis, the Chinese Academy of Sciences, and Zhejiang University are front runners in research related to these areas. Future research could be extended to the development of technologies for on-site recovery of resources, exploring integrated resource recovery pathways, and exploring different safe waste processing methods

Pathways for the Valorization of Animal and Human Waste to Biofuels, Sustainable Materials and Value-Added Chemicals

Human and animal waste, including waste products originating from human or animal digestive systems such as urine, feces, and animal manure, have constituted a nuisance to the environment. Inappropriate disposal and poor sanitation of human and animal waste often cause negative impacts on human health through contamination of the terrestrial environment, soil, and water bodies. Therefore, it is necessary to convert these wastes into useful resources to mitigate their adverse environmental effect. The present study provides an overview and research progress of different thermochemical and biological conversion pathways for the transformation of human- and animal-derived waste into valuable resources. The physicochemical properties of human and animal waste are meticulously discussed as well as nutrient recovery strategies. In addition, a bibliometric analysis is provided to identify the trends in research and knowledge gaps. The results reveal that the U.S.A, China and England are the dominant countries in the research areas related to resource recovery from human or animal waste. In addition, researchers from the University of Illinois, the University of California Davis, the Chinese Academy of Science and Zhejiang University are front runners in research related to these areas. Future research should be centred on developing technologies for the on-site recovery of resources, exploring integrated resource recovery pathways, and exploring different safe waste processing methods

Development and Performance Evaluation of a Ceramic Filter for Point-of-Use Water Purification

In this work, a ceramic filter for point-of-use water purification was designed, fabricated and tested to evaluate its performance in filtering water to the World Health Organisation (WHO) standards. The results of pH of water samples obtained after filtration ranged from 7.68 to 8.11. The range of values obtained after filtration for turbidity, hardness, conductivity, total dissolved solid (TDS) and total suspended solid (TSS) from water samples were 0.07 to 0.55 NTU, 6.0 to 34 mg/L, (1.5 to 3.3) x 10 -3 S/m, 4 to 25 mg/L and 0.04 to 0.11 mg/L, respectively, while the filter average removal efficiencies of these parameters were 93.1, 85.1, 91.6, 92.3 and 91.4%, respectively. Comparison of the results with the WHO standards for drinking water showed that the ceramic water filter can provide potable drinking water of required standard

Process design, exergy, and economic assessment of a conceptual mobile autothermal methane pyrolysis unit for onsite hydrogen production

The present study proposes a conceptual mobile autothermal methane pyrolysis unit for onsite hydrogen production. Considering the shortage of hydrogen pipeline infrastructure between production plants and fuelling stations in most places where hydrogen is required, it is imperative to create alternative hydrogen production means. The design combines a catalytic plasma methane pyrolysis unit with a steam char gasification setup, combustion, and biomethanation unit for hydrogen production. The reactor design includes Ni - Br in a bubble column acting as a catalyst. Energy and exergy calculations followed by a comprehensive economic analysis were appraised to evaluate the efficiency and performance of the integrated process. The levelized cost of hydrogen (LCOH) from the conceptual design ranged from 1.3 to 1.47 U.S.$/kg, while the proposed design's net present value (NPV) was in the range of 3.76 – 4.35 M.U.S.$. Factors such as equipment purchase cost (EPC) and feedstock cost significantly influenced the NPV and LCOH. In addition, a positive NPV and lower LCOH outline the proposed design's profitability. Finally, an optimized methane conversion of 76.8 % was obtained from the study

Global age-sex-specific mortality, life expectancy, and population estimates in 204 countries and territories and 811 subnational locations, 1950–2021, and the impact of the COVID-19 pandemic: a comprehensive demographic analysis for the Global Burden of Disease Study 2021

BackgroundEstimates of demographic metrics are crucial to assess levels and trends of population health outcomes. The profound impact of the COVID-19 pandemic on populations worldwide has underscored the need for timely estimates to understand this unprecedented event within the context of long-term population health trends. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 provides new demographic estimates for 204 countries and territories and 811 additional subnational locations from 1950 to 2021, with a particular emphasis on changes in mortality and life expectancy that occurred during the 2020–21 COVID-19 pandemic period.Methods22 223 data sources from vital registration, sample registration, surveys, censuses, and other sources were used to estimate mortality, with a subset of these sources used exclusively to estimate excess mortality due to the COVID-19 pandemic. 2026 data sources were used for population estimation. Additional sources were used to estimate migration; the effects of the HIV epidemic; and demographic discontinuities due to conflicts, famines, natural disasters, and pandemics, which are used as inputs for estimating mortality and population. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate under-5 mortality rates, which synthesised 30 763 location-years of vital registration and sample registration data, 1365 surveys and censuses, and 80 other sources. ST-GPR was also used to estimate adult mortality (between ages 15 and 59 years) based on information from 31 642 location-years of vital registration and sample registration data, 355 surveys and censuses, and 24 other sources. Estimates of child and adult mortality rates were then used to generate life tables with a relational model life table system. For countries with large HIV epidemics, life tables were adjusted using independent estimates of HIV-specific mortality generated via an epidemiological analysis of HIV prevalence surveys, antenatal clinic serosurveillance, and other data sources. Excess mortality due to the COVID-19 pandemic in 2020 and 2021 was determined by subtracting observed all-cause mortality (adjusted for late registration and mortality anomalies) from the mortality expected in the absence of the pandemic. Expected mortality was calculated based on historical trends using an ensemble of models. In location-years where all-cause mortality data were unavailable, we estimated excess mortality rates using a regression model with covariates pertaining to the pandemic. Population size was computed using a Bayesian hierarchical cohort component model. Life expectancy was calculated using age-specific mortality rates and standard demographic methods. Uncertainty intervals (UIs) were calculated for every metric using the 25th and 975th ordered values from a 1000-draw posterior distribution.FindingsGlobal all-cause mortality followed two distinct patterns over the study period: age-standardised mortality rates declined between 1950 and 2019 (a 62·8% [95% UI 60·5–65·1] decline), and increased during the COVID-19 pandemic period (2020–21; 5·1% [0·9–9·6] increase). In contrast with the overall reverse in mortality trends during the pandemic period, child mortality continued to decline, with 4·66 million (3·98–5·50) global deaths in children younger than 5 years in 2021 compared with 5·21 million (4·50–6·01) in 2019. An estimated 131 million (126–137) people died globally from all causes in 2020 and 2021 combined, of which 15·9 million (14·7–17·2) were due to the COVID-19 pandemic (measured by excess mortality, which includes deaths directly due to SARS-CoV-2 infection and those indirectly due to other social, economic, or behavioural changes associated with the pandemic). Excess mortality rates exceeded 150 deaths per 100 000 population during at least one year of the pandemic in 80 countries and territories, whereas 20 nations had a negative excess mortality rate in 2020 or 2021, indicating that all-cause mortality in these countries was lower during the pandemic than expected based on historical trends. Between 1950 and 2021, global life expectancy at birth increased by 22·7 years (20·8–24·8), from 49·0 years (46·7–51·3) to 71·7 years (70·9–72·5). Global life expectancy at birth declined by 1·6 years (1·0–2·2) between 2019 and 2021, reversing historical trends. An increase in life expectancy was only observed in 32 (15·7%) of 204 countries and territories between 2019 and 2021. The global population reached 7·89 billion (7·67–8·13) people in 2021, by which time 56 of 204 countries and territories had peaked and subsequently populations have declined. The largest proportion of population growth between 2020 and 2021 was in sub-Saharan Africa (39·5% [28·4–52·7]) and south Asia (26·3% [9·0–44·7]). From 2000 to 2021, the ratio of the population aged 65 years and older to the population aged younger than 15 years increased in 188 (92·2%) of 204 nations.InterpretationGlobal adult mortality rates markedly increased during the COVID-19 pandemic in 2020 and 2021, reversing past decreasing trends, while child mortality rates continued to decline, albeit more slowly than in earlier years. Although COVID-19 had a substantial impact on many demographic indicators during the first 2 years of the pandemic, overall global health progress over the 72 years evaluated has been profound, with considerable improvements in mortality and life expectancy. Additionally, we observed a deceleration of global population growth since 2017, despite steady or increasing growth in lower-income countries, combined with a continued global shift of population age structures towards older ages. These demographic changes will likely present future challenges to health systems, economies, and societies. The comprehensive demographic estimates reported here will enable researchers, policy makers, health practitioners, and other key stakeholders to better understand and address the profound changes that have occurred in the global health landscape following the first 2 years of the COVID-19 pandemic, and longer-term trends beyond the pandemic