Characterization of Doum Palm Seed Kernel as Natural Sorbent for Metal Ions Removal from Gombe Ternary Wastewater

Water pollution is one of the major challenges in cities and industrialized areas of the world. The effluent from Gombe ternary wastewater pollutes the surrounding waters thereby constituting health threat to the populace within its vicinity. In view of the above, a bio-sorption study of zinc and lead ions from Gombe ternary wastewater using doum palm seed kernel was carried out. The wastewater was characterized and was found to contain 0.03 mg/l lead metal ion and 0.81 mg/l zinc ion. The doum palm kernel bio-sorbent was obtained after oil extraction from the seed and processed as contained in the method mentioned in this paper. The kernel residue was characterized for functional groups using FTIR, surface morphology using SEM, surface area using BET, and elemental composition using XRF. The results indicated that the doum palm kernel is harmless, and possesses functional groups on its surface, which may be substituted with the metallic ions present in the wastewater. This gives the kernel the ability to adsorb positively charged ions on its surface by simple chemisorption. This mechanism is supported by the rough surface observed in the scanning electron microscopy. Adsorption and desorption of nitrogen was made at STP and the curve indicated very high correlation of close to unity. The surface area measured by multi BET method was recorded as 13.464 m2/g. This value is not high enough to adsorb metals by physical adsorption

Synthesis of Supported Metallocene Catalysts and Application to Copolymerization of Ethylene with 4-Methyl-1-pentene

In the family of commodity polyolefins, linear low density polyethylene (LLDPE)a copolymer of ethylene and -olefinis the latest addition. LLDPEs have wide applications. Therefore, all the nine (9) Saudi petrochemical industries produce LLDPEs. The total production volume is about 4 million metric tons per annum which places Saudi Arabia as the largest LLDPE producer in the Middle East and within top five in theworld. LLDPEs are mostly produced by low pressure conventional supported catalysts. In this regard, the versatility of catalyst type and polymer synthesis methodology creates new knowledge. This eventually makes new polymeric materials for advanced applications. Metallocenes are a modern innovation in polyolefin catalysis, and have several advantages over the Ziegler-Natta catalysts. Hence, the overall objective of the proposed study is to synthesize various supported metallocene catalysts with varying anions, and apply them to prepare ethylene-1-hexene and ethylene-4-methyl-1-pentene copolymers. In this work, the supported metallocene catalysts were prepared using the following order: dehydroxylated silica (alone or functionalized with ClSiMe2Cl), methylaluminoxane (MAO) cocatalyst and (nBuCp)2ZrCl2). These catalyst systems were applied to homo- or copolymerize ethylene with 4-methyl-1-pentene as well as its isomer 1-hexene, using solution, in-situ, and slurry polymerization trials. In the latter two modes of polymerizations, no MAO was fed separately into the reactor. The variations in the polymerization processes varied the MAO cocatalyst anions. The effects of the resulting cocatalyst anions on polymerization performance and the product properties were elaborately studied by determining the reactor operability and catalyst productivity, and by characterizing the polymers using gel permeation chromatography, Fourier Transform infra-red spectroscopy, 13C NMR spectroscopy, differential scanning calorimetry (DSC), successive self-nucleation and annealing (SSA) thermal fractionation, and crystallization fractionation technique (Crystaf). This study has advanced the fundamental understanding of supported metallocene catalysis and development of ethylene--olefin copolymers as follows. The functionalizing linker ClSiMe2Cl did not affect the catalyst productivity. The supported systems showed similar productivity as the solution polymerization which is hardly reported in the literature. The distributive as well as the bulk properties of the polymers varied with the MAO anion design. This understanding produced selected application-specific polymers. The copolymerization mechanism was found to be well predicted by the first order Markovian (terminal) model. ClSiMe2Cl suppressed chain transfer reactions in the supported catalyst. Microstructural properties, determined using 13C NMR/SSA-DSC, elaborated how supported MAO anions made copolymer backbones with compositional heterogeneity. The nonisothermal Avrami-Erofeev crystallization model well matched the experimental data notably for Avrami-Erofeev index of 2 to 3. This shows bi- and tri-dimensional crystal growth. The apparent crystallization activation energy, predicted by the Avrami-Erofeev crystallization model, did not depend on the cooling rates. This finding, therefore, refutes the concept of instantaneous variable crystallization activation energy, articulated in the literature. Furthermore, the crystallization model successfully elaborated the influence of compositional heterogeneity on copolymer crystallization behavior. So far as product development is concerned, this study shows how to synthesize LLDPEs that are blocky and more degradation-resistant, have improved processability (fairly low melting point and crystallinity), and that can be used for load-bearing applications

Synthesis of Supported Metallocene Catalysts and Application to Copolymerization of Ethylene with 4-Methyl-1-pentene

In the family of commodity polyolefins, linear low density polyethylene (LLDPE)a copolymer of ethylene and -olefinis the latest addition. LLDPEs have wide applications. Therefore, all the nine (9) Saudi petrochemical industries produce LLDPEs. The total production volume is about 4 million metric tons per annum which places Saudi Arabia as the largest LLDPE producer in the Middle East and within top five in theworld. LLDPEs are mostly produced by low pressure conventional supported catalysts. In this regard, the versatility of catalyst type and polymer synthesis methodology creates new knowledge. This eventually makes new polymeric materials for advanced applications. Metallocenes are a modern innovation in polyolefin catalysis, and have several advantages over the Ziegler-Natta catalysts. Hence, the overall objective of the proposed study is to synthesize various supported metallocene catalysts with varying anions, and apply them to prepare ethylene-1-hexene and ethylene-4-methyl-1-pentene copolymers. In this work, the supported metallocene catalysts were prepared using the following order: dehydroxylated silica (alone or functionalized with ClSiMe2Cl), methylaluminoxane (MAO) cocatalyst and (nBuCp)2ZrCl2). These catalyst systems were applied to homo- or copolymerize ethylene with 4-methyl-1-pentene as well as its isomer 1-hexene, using solution, in-situ, and slurry polymerization trials. In the latter two modes of polymerizations, no MAO was fed separately into the reactor. The variations in the polymerization processes varied the MAO cocatalyst anions. The effects of the resulting cocatalyst anions on polymerization performance and the product properties were elaborately studied by determining the reactor operability and catalyst productivity, and by characterizing the polymers using gel permeation chromatography, Fourier Transform infra-red spectroscopy, 13C NMR spectroscopy, differential scanning calorimetry (DSC), successive self-nucleation and annealing (SSA) thermal fractionation, and crystallization fractionation technique (Crystaf). This study has advanced the fundamental understanding of supported metallocene catalysis and development of ethylene--olefin copolymers as follows. The functionalizing linker ClSiMe2Cl did not affect the catalyst productivity. The supported systems showed similar productivity as the solution polymerization which is hardly reported in the literature. The distributive as well as the bulk properties of the polymers varied with the MAO anion design. This understanding produced selected application-specific polymers. The copolymerization mechanism was found to be well predicted by the first order Markovian (terminal) model. ClSiMe2Cl suppressed chain transfer reactions in the supported catalyst. Microstructural properties, determined using 13C NMR/SSA-DSC, elaborated how supported MAO anions made copolymer backbones with compositional heterogeneity. The nonisothermal Avrami-Erofeev crystallization model well matched the experimental data notably for Avrami-Erofeev index of 2 to 3. This shows bi- and tri-dimensional crystal growth. The apparent crystallization activation energy, predicted by the Avrami-Erofeev crystallization model, did not depend on the cooling rates. This finding, therefore, refutes the concept of instantaneous variable crystallization activation energy, articulated in the literature. Furthermore, the crystallization model successfully elaborated the influence of compositional heterogeneity on copolymer crystallization behavior. So far as product development is concerned, this study shows how to synthesize LLDPEs that are blocky and more degradation-resistant, have improved processability (fairly low melting point and crystallinity), and that can be used for load-bearing applications

Energy Consumption and Economic Growth: Evidence from Developed and Emerging Markets

This research analyzed the effect of energy consumption on economic growth using neo-classical one-sector aggregate production function with panel data from Emerging Markets and Developed countries over the period 2000–2013. This study has applied dynamic panel method in the form of two-step panel Generalized Method of Moments (both difference and system) GMM. The findings of this research exposed that both gross fixed capital formation and energy consumption have significant and positive effect on economic growth in both Developed and Emerging Market countries. In addition, labour force has been found to influence positively on economic growth in the group of Developed Market countries. However, labour force established the significant as well as negative effect on economic growth in the Frontier Market countries. Since the findings revealed that all the sampled countries are energy dependent, therefore, their policy makers should continue to promote the development of energy infrastructure with the aim to gain higher economic growth by making effective energy policies. This can be achieved through the allocation of more resources to the development of new sources of energy and ensure sustainability of energy use

Extraction of the pulse width and pulse repetition period of linear FM radar signal using time-frequency analysis

A common technique used by military to realize low probability of intercept (LPI) is linear frequency modulation (LFM) in the field of electronic intelligence (ELINT). This paper estimates the pulse width (PW) and the pulse repetition period (PRP) of LFM signal using instantaneous powers. The instantaneous powers were obtained either using time-marginal or power maxima approximated from a modified version of the Wigner-Ville distribution (WVD). The instantaneous power was also gotten directly from the signal by multiplication with its conjugate. Measurement was then carried out when the instantaneous power is ‘ON’ (the PW) and when it is ‘OFF’ (the PRP) at carefully selected thresholds. Thereafter, the mWVD-based algorithm was tested in the presence of additive white Gaussian noise (AWGN) at various signal-to-noise ratios. Results obtained during the test showed that the time marginal method emerged the best with minimum signal-to-noise ratio (SNR) of -5dB followed closely by the direct method with minimum SNR of -1dB at different thresholds. The results show that the proposed algorithm based on this modified WVD can be deployed in the practical field to determine radar’s performance and functio

Reference values of somatometric and sonographic renal parameters of apparently healthy Hausa children in Kano metropolis, Nigeria

Accurate measurement of organ size is important in children to estimate adequate growth. Among various growth parameters, kidney size is an important parameter used for the clinical evaluation of renal growth and renal abnormalities. The study is aimed at evaluating the renal volume using ultrasound scan in normal Hausa primary school children in Kano aged 2 to 13 years. The study design was prospective cross sectional conducted among healthy Hausa children, aged 2 to 13 in Kano metropolis from October 2017 to October 2019. Approval to carry out the study was obtained from the State Universal Basic Education, Kano, Ministry of Health, Kano. Informed oral and written consent were obtained from the child’s parents or caregiver. A simple random sampling was employed in the study and a total of 457 subjects were recruited. The instrument used was MindrayDigiprince DP4900 ultrasound machines with 3.5 – 5.0MHz curvilinear transducer. Renal ultrasound scan was performed on all the selected subjects. SPSS version 22.0 was used for the data analysis. The mean heights, weights and BMI of the subjects were 1.21±0.11m, 20.46±4.92kg and 13.93kg/m2. The mean renal length, thickness, width and renal volume were 7.69±0.71cm, 3.31 ± 0.42cm, 4.80 ± 0.49cm and 64.79±16.13cm3 respectively. This study provides data for normal sonographic renal volume and length in Kano metropolis, a Hausa dominated Nigerian population

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries