Kinetics of the homogeneous reaction between palladium compounds and hydrazine, forming metal nuclei

Imperial Users onl

The Effect of using Concept Maps on Student Achievement in Selected Topics in Chemistry at Tertiary Level

The performance in chemistry at tertiary level in Zambia has not been as expected. It has therefore been a matter of concern. There has been a continuous focus on exploring new teaching strategies to improve the understanding of this difficult subject. This study investigated the effectiveness of composite use of concept maps and traditional method on student achievement in selected topics in chemistry. The study was conducted in view of determining the method which is more effective in enhancing student understanding in chemistry. There were three groups involved in the study i.e. Control, experimental group1 and experimental group 2. The pre-test, post –test true experimental research design was used for the study.  The sample of the study consisted of thirty nine (39) first year students at Mufulira College of education. Each of the three groups was randomly assigned 13 students. The treatment took four weeks using the topics “atomic structure” and “chemical bonding”. The control group was treated using the traditional method, the experimental group 1 was treated using the concept map method while experimental group 2 used composite of both the traditional and concept map methods.  One way ANOVA at an alpha (α) = .05 was conducted to analyze the results of the pre- test and post test scores. The means of the pre-test scores were; control group = 6.46, Experimental group 1 = 7.07 and experimental group 2 = 6.61. These results show that there was no significant difference in the performance of the students in all groups. This result implied that the entry level performance for all the groups was not significantly different.  The means of the post-test results(control group = 4.53,experimental group1 = 5.46, experimental group 2 = 6.61) showed that there was a significant effect on the use of  both traditional teaching method and concept map teaching method at p < .05 level for the three groups at F(2,36) = 17.156  , p = 0.00. The experimental group 2 performed better than both control group and experimental group 1 in the post test scores. Post hoc comparisons using the Turkey HSD test indicated that the mean scores were significantly different. The results strongly support that when students are taught using both the concept map teaching strategy and traditional teaching strategy, they achieve the best scores. This study therefore offers an encouraging solution towards improvement of student performance in Chemistry at tertiary level. Key words: Concept map, Traditional method, experimental group, achievement, effective method.

Effect of Ethnochemistry Practices on Secondary School Students’ Attitude Towards Chemistry

The main purpose of the study was to find out the effect of ethnochemistry practices on secondary school students’ attitude towards Chemistry.  The design of the study was pre-test post-test control group quasi-experimental design. Two grade 11 intact classes were assigned into experimental and control groups randomly. The total sample size comprised 113 students. To assess attitude of the student towards Chemistry, a chemistry attitude questionnaire was used. An independent samples t-test at an alpha (α) = .05 was conducted to analyze the results of the pre-test and post-test scores. There was a statistically significant difference in the post-test attitude scores for control (M=74.71, SD=13.90) and experimental (M=83.36, S=14.68) groups; t (111) = -3.22, p = 0.002.  Therefore, incorporating ethnochemistry practices in teaching chemistry was found to have a positive effect on enhancing secondary school students’ attitude towards Chemistry. Keywords: Ethnochemistry, Conventional approach, Attitud

Composite Effect of Concept Mapping and ICT on Students’ Performance in Organic Chemistry

Generally, the performance of students in organic chemistry in Zambia is not encouraging. This can be attributed to the nature of the subject in addition to other factors. This study explored the composite effect of concept mapping and ICT on students’ performance in selected topics in organic chemistry. One hundred and thirty-four grade 12 students were involved. Data was collected using an organic chemistry performance test. A pre-test, the post-test quasi-experimental design was adopted. The study comprised of three groups randomly assigned to experimental group one, experimental group two and a control group. Experimental group one was taught using concept mapping, experimental group two was taught using a combination of concept mapping and ICT and the control group was taught using conventional methods (discussion). ANOVA results for the three groups were F (2,131) = 2.237 and p = 0.111. This indicates that there was no significant difference amongst the three groups at the beginning of the study. After treatment the results revealed that experimental group two outperformed the other two groups with a p valuep-value 0 at F (2,131) = 2.237 at ? = 0.05. Post hoc analysis using Fisher’s Least Significant Difference (LSD) test showed that the mean scores were statistically significant amongst the three groups. A very large effect was seen between experimental group one and control and between experimental group two and control. A sizable effect was seen between experimental group one and two. The conclusion is that using concept mapping with ICT has a positive effect on the performance of students in organic chemistry. The results corroborate the findings of studies that the use of concept mapping and ICT teaching strategy improves the performance of students. Consequently, this study seems to offer a positive solution towards the enhancement of students’ performance in organic chemistry in secondary schools

Utilisation of Bagasse Fly Ash and Carbon Waste from Fertiliser Plant for Treatment of Pyridine and 3-Picoline Bearing Wastewater

The present work explores the possibility of utilizing sugarcane bagasse fly ash and carbon waste obtained from sugar mills and nitrogenous fertilizer plants, respectively for the removal of pyridine and 3-picoline from waste water. The adsorbing capacity of both adsorbents has been compared with that of activated carbon. Batch studies were conducted to see the effect of contact time, adsorbent dose, initial concentration and pH on the removal of pyridine and 3-picoline. Equilibrium data were fitted with Langmuir and Freundlich isotherms. Adsorptive capacities were found to be in the order: activated carbon \u3e carbon waste \u3e bagasse fly ash. Adsorption was found to follow first order kinetics and intra-particle diffusion was found to be rate controlling. Two-stage batch adsorption (using bagasse fly ash and carbon waste) was found to give 85-100% removal of pyridine. Column studies were also conducted for the removal of pyridine using bagasse fly ash as adsorbent. BDST model was used to analyze the column data

Evaluation of physicochemical properties with the availability of plant nutrients in forests and crop farms in different Fijian provinces

Soils are the foundation of agriculture and forestry and it provides many functions such as the supply of water and nutrients and anchorage for plant growth and more. Forest farming and agriculture farming are 2 entities of the ecosystem and they may lead to changes in soil properties. To cope with the challenges in the soil management system, data on current chemical and physical soil properties are more necessary. Therefore, we present a comparative study on soil properties existing in soil and forest farms of Fiji Island. Soil samples from 24 different locations were collected from 8 sites based on the heterogeneity and land use of soils, keeping in view the variation in soil type and slope to determine physicochemical properties and nutrient status. The physical properties such as bulk density (1.05-1.20 Mg m-3), percent porosity (54.14-56.62), moisture % (16.78-18.53%) and soil permeability (11.79-12.35 cm hour-1 was comparatively higher in forest farms compared to the agricultural farms. The soil pH in forest farms and agriculture farms ranged from 5.42-6.10 and 5.30-5.61 respectively. A higher range of CEC was found in forest farms (17.7-19.2) may be due to the higher amount of soil organic matter in forest farms in comparison to agricultural farms. The results also showed that the nutrients such as N, P, K, Ca and Mg and micronutrients (Cu, Fe, Mn and Zn) values were low on the agricultural farms.  The study suggests the combined use of good agricultural practices, limited use of agrochemicals and minimal soil disturbance at agriculture farms to prevent further degradation, acidification and nutrient stocks.

Phytochemical analysis and antioxidant potential of Pseudolachnostylis maprouneifolia

Pseudolachnostylis maproneifolia is a popular medicinal plant, particularly revered in the eastern province of Zambia, especially within Petauke District. Despite its widespread application in traditional medicine, the chemical composition of this plant has not been studied so far. Consequently, there was a pressing need to investigate the medicinal potential of its leaf extract. This study was carried out through preliminary phytochemical screening and GC-MS analysis of the ethanolic extract. The phytochemical profile revealed various secondary metabolites endowed with antifungal, anti-inflammatory, anti-tumor, anti-cancer, antibacterial, antiviral, and antioxidative properties. To quantify its medicinal potential, the total flavonoid content (TFC) and total phenolic content (TPC) was determined using a UV-Vis spectrophotometer. The methanolic extract exhibited a TFC of 157.20 mg QE/g and a TPC of 63.75 mg GAE/g, with an IC50 value of 45.57 μg/mL, signifying a strong antioxidant capability. Notably, the IC50 value of the standard (ascorbic acid) was 23.19 μg/mL. Further analysis involved quantifying the mineral elements crucial for treating anemia, such as iron, copper, zinc, and manganese. AAS based analysis revealed concentrations of these elements to be relatively higher, indicating their suitability for treating anemia. Complementing these findings, in silico molecular analysis and ADMET analysis of five selected phytochemicals, along with a reference cancer drug, yielded promising results such as a highest binding energy of -9.01 Kcal/mol, high gastrointestinal absorption and the lowest inhibition constant of 249.88 nM. These outcomes strongly advocate for subsequent in vitro and in vivo studies on these molecules, supporting their importance as potential drug candidates for cancer drug development

Studies on the Use of Carbon Waste Generated from Fertiliser Plant in Waste Water Treatment

Carbon waste generated from fertiliser plant has been used for adsorption studies for the removal of chromium, zinc and nickel and COD from industrial effluent from phenol formaldehyde plant, polyester plant, sugar plant. Removal to the extent of 91.40, 86.8, 93.8 percent was achieved at the initial concentration of 10 mg/1 for Cr(VI), Ni(TI) and Zn(II) respectively using carbon waste as adsorbent Removal of these metals were found to be in order of Zn(II) \u3e Cr(VI) \u3e Ni(II). In a multi cationic solution containing these three metals, Cr(VI) adsorbed preferentially over Ni(II) and Zn(II). COD removal of 67.51%, and 86.4 % was obtained in case of polyester and sugar plant effluent respectively. In case of phenol formaldehyde resin COD removal to the extent of 65.00 % was obtained for the initial COD concentration of 1000mg/l

Technological Perspectives of Countering UAV Swarms

Conventional AD systems have been found less effective for countering UAVs and loitering munitions. Thishas necessitated the development of counter-UAV systems with different functionalities. A cluster of armed UAVsas swarm formations has further rendered the conventional AD systems far from effective, emphasizing the need to consider countering swarms as the most crucial element in new-generation aerial threat mitigation strategies. In this paper, the capabilities of UAV swarms and vital military assets exposed to such attacks are identified. To protect the vital assets from aerial swarm threats, ideal system characteristics of a counter-UAV (C-UAV) swarm system to overcome the challenges are discussed. Currently available acquisition & engagement technology is analyzed and the application of these systems to counter swarm applications is brought out. New requirements are discussed and a conceptual design of a layered system is derived which can handle a large spectrum of aerial threats including a swarm of UAVs. This system is expected to have a higher rate of engagement and can be designed with low-cost network-integrated systems

LaSrVMoO6_6: A case study for AA-site covalency-driven local cationic order in double perovskites

An unusual atomic scale chemical fluctuation in LaSrVMoO$_6$, in terms of narrow patches of La,V and Sr,Mo-rich phases, has been probed in detail to understand the origin of such a chemical state. Exhaustive tuning of the equilibrium synthesis parameters showed that the extent of phase separation can never be melted down below an unit cell dimension making it impossible to achieve the conventional $B$-site ordered structure, which establishes that the observed `inhomogeneous' patch-like structure with minimum dimension of few angstroms is a reality in LaSrVMoO$_6$. Therefore, another type of local chemical order, hitherto unknown in double perovskites, gets introduced here. X-ray diffraction, electron microscopy elemental mapping, magnetic, and various spectroscopic studies have been carried out on samples, synthesized under different conditions. These experimental results in conjunction with {\it ab-initio} electronic structure calculation revealed that it is the energy stability, gained by typical La-O covalency as in LaVO$_3$, that leads to the preferential La,V and Sr,Mo ionic proximity, and the consequent patchy structure.Comment: 21 pages, 7 figure