Percentage Of Carbon Content Research Articles

Simplified oxygen-limited thermal treatment without tube furnace and inert gas

The article introduces a cost-effective and user-friendly alternative to traditional pyrolysis techniques, obviating the necessity for intricate tube furnaces and inert gas environments. This novel approach employs materials capable of reacting with and sequestering oxygen to establish an oxygen-depleted atmosphere. The experimental setup entails positioning a crucible containing the sample inside a ceramic pot, enveloped by varying sizes of wood coal particles, and subsequently subjecting the ceramic pot to furnace conditions. Utilizing this oxygen-limited strategy, a biochar sample, derived via hydrothermal processing, underwent carbonization at 650°C for 6.5 hours, with outcomes compared against ambient condition carbonization under identical temperature and duration parameters. Gravimetric analysis revealed that wood coal effectively curtails oxygen availability, augmenting biochar yield from 1.53 % to 19.50 %. Fourier-transform infrared spectroscopy (FTIR) indicates diminished oxygen functional groups, while X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM) affirmed a denser, compact carbon structure in biochar produced under oxygen-restricted conditions versus ambient conditions. The carbon content percentage in biochar samples treated at 650°C for 6.5 hours under both conditions was assessed via energy-dispersive X-ray spectroscopy (EDX) data. The emergence of a novel carbon nanomaterial, derived from biomass waste through our oxygen-limiting method, may exhibits applications in energy storage and water purification. Our approach offers simplicity, cost-efficiency, and straightforward implementation while upholding the integrity of pyrolysis/thermal treatment within inert conditions, ensuring the robustness of the procedure.

Production of biodiesel from palm kernel oil through base-catalyzed trans-esterification process

Growing concerns about environmental problems associated with fuels have engineered so much research into biofuels, such as biodiesel. However, continuous and large-scale production of biodiesel from edible oil could result in serious food security problems if cheap and viable alternatives are not made available. To solve this problem, oil was obtained from non-food/ underutilized seeds of palm kernel using Soxhlet apparatus. Physicochemical properties and fatty acids composition of these oils were determined using standard analytical and instrumental methods. Biodiesel was processed from these oils via sequential base (KOH) homogeneous catalysis. Fuel properties of biodiesel from the oil were determined using standard methods and the results obtained were compared with standards. Oil yields were found to be 37.6% for palm kernel seed respectively. Physicochemical properties of palm kernel oil respectively are: saponification value:(115.00)mg KOH/g, acid value(4.488)mgKOH/g, free fatty acid value (2.244)mg/KOH/viscosity:(29)mm2/s, moisture content: (0.46)%, peroxide value:(3.12)meqkg-1,refractive index:(1.455), specific gravity (0.899)g/cm. Fuel properties of biodiesel from palm kernel seed oil respectively are: Kinematic viscosity at 40oc: (nil) mm2/s, smoke point (100oc), flash point(90oc),fire point:(150oc),pour point(nil) and cloud point:(nil).The physicochemical properties of the biodiesel produced showed that the flash point, viscosity, density, ash content, percentage carbon content, specific gravity and the acid value fell within American Society for Testing and Materials (ASTM) specifications for biodiesel. Therefore, the biodiesel produced from the oil significantly met standard quality requirements.

Preparation and characterization of stationary phase gradients on C8 liquid chromatography columns

Continuous C8 stationary phase gradients are created on commercial Waters Symmetry Shield RP8 columns by strategically cleaving the C8 moieties in a time-dependent fashion. The method relies on the controlled infusion of a trifluoroacetic acid/water/acetonitrile solution through the column to cleave the organic functionality (e.g., C8) from the siloxane framework. The bond cleavage solution is reactive enough to cleave the functional groups, even with polar groups embedded within the stationary phase to protect the silica. Both the longitudinal and radial heterogeneity were evaluated by extruding the silica powder into polyethylene tubing and evaluating the percent carbon content in the different sections using thermogravimetric analysis (TGA). TGA analysis shows the presence of a stationary phase gradient in the longitudinal direction but not in the radial direction. Two different gradient profiles were formed with good reproducibility by modifying the infusion method: one exhibited an ‘S’-shaped gradient while the other exhibited a steep exponential-like gradient. The gradients were characterized chromatographically using test mixtures, and the results showed varied retention characteristics and an enhanced ability to resolve nicotine analytes.

Assessment of Ovbiomu Coal for Industrial Application

This research is to assess the quality of Ovbiomu lignite coal deposited for optimum utilization in metallurgical industries in Ovbiomu. Samples of coal were collected for analysis and sample was collected from five different stationary lots until 10 kilograms of the sample was collected and 500g was taken for characterization. The sample was reduced using jaw crusher and ball milled to a size of 1400μm and 1 kilograms of 1400μm was further reduced to 1100μm and was classified into various sieve sizes using mechanical sieve shaker. CalK2 bomb calorimeter was used to determine the calorific value of the head sample, the economic liberation size and the actual liberation size. The proximate analysis of the head sample and all the sieve sizes was done using Furnace, oven, porcelain crucibles, analytical balance, and desiccator to ascertain the individual carbon content. Ultimate analysis was done using XRD and concentration was done using froth flotation method. Result from sieve analysis shows that at 1000 μm, 710 μm, 500 μm, 355 μm, 250 μm, 180 μm, 25 μm, 90 μm, 63 μm, and -63 μm, the following weight was retained 1.45 g 1.86 g, 3.73 g, 3.5 g, 14.61 g, 48.28 g, 0.15 g, 0.17 g and 0.20 g respectively. The economic liberation size was found out to be 180um where most of the sample is retained and the actual liberation size was found out to be 125um but with a very small quantity retained. The results of the calorific value of the head sample and each of the sieve sizes of 250μm, 180μm, and 125μm, was determined to be 24.51MJ/Kg, 25.86MJ/Kj, 18.57MJ/Kg and 38.07MJ/Kg respectively, the following are result of percentage carbon content, for the Head sample (40.65%), 1000μm (29.55%), 710μm (38.53%), 500μm (42.43%), 335μm (35.42%), 250μm(43.07%), 180μm (30.92),125μm (63.40%) 90μm (0.56%) 63μm (0.62%) and -63μm (9.91%). The result of ultimate analysis of the sample shows Nitrogen (1.15%), Hydrogen (4.80%), Sulphur (0.13%) and Oxygen (29.56%).

Predicting Aboveground Biomass and Carbon Storage for Ma Bamboo (Dendrocalamus latiflorus Munro) Plantations

The purpose of this study was to predict aboveground biomass (AGB) and aboveground carbon storage (AGCS) in Ma bamboo (Dendrocalamus latiflorus Munro) plantations. A total of 25 bamboo samples were selected and felled based on age and diameter at breast height (DBH) classes. Two types of allometric equations (with and without an age factor) were used to develop biomass models for foliage, branches, culms and aboveground parts. Moreover, three intensively managed Ma bamboo plantations were used in this study to predict AGB and AGCS. The above two biomass models and a diameter distribution model were used to predict AGB for the three bamboo stands. The AGCS was predicted based on the AGB and percent carbon content. The results showed that the proportions of foliage, branches and culms to AGB were 11.1, 23.7 and 65.2%, respectively, at the individual bamboo level. The mean percent carbon content was predicted to be 41.68, 44.21 and 46.72% for foliage, branches and culms, respectively. The allometric equation with the age factor had better predictive ability than that without the age factor, with the former having higher R2 and lower root mean square error values. Compared to the AGB predicted by the allometric model with the age factor at the stand level, the range of relative error was from −16.56 to 5.26% and from −40.0 to 71.7% for the AGB predicted by the allometric model without the age factor and that by the diameter distribution model, respectively. According to the allometric model with the age factor, the AGB and AGCS were predicted to be 35.7 ± 3.4 and 16.3 ± 1.5 Mg ha−1, respectively, in Ma bamboo plantations. The results also reflected that the current status of Ma bamboo management is intensive management, where the focus is on harvesting bamboo shoots.

Utilization of Bacillus cereus strain CGK5 associated with cow feces in the degradation of commercially available high-density polyethylene (HDPE).

The accumulation and mismanagement of high-density polyethylene (HDPE) waste in the environment is a complex problem in the present scenario. Biodegradation of this thermoplastic polymer is a promising environmentally sustainable method that offers a significant opportunity to address plastic waste management with minimal negative repercussion on the environment. In this framework, HDPE-degrading bacterium strain CGK5 was isolated from the fecal matter of cow. The biodegradation efficiency of strain was assessed, including percentage reduction in HDPE weight, cell surface hydrophobicity, extracellular biosurfactant production, viability of surface adhered cells, as well as biomass in terms of protein content. Through molecular techniques, strain CGK5 was identified as Bacillus cereus. Significant weight loss of 1.83% was observed in the HDPE film treated with strain CGK5 for 90days. The FE-SEM analysis revealed the profused bacterial growth which ultimately caused the distortions in HDPE films. Furthermore, EDX study indicated a significant decrease in percentage carbon content at atomic level, whereas FTIR analysis confirmed chemical groups' transformation as well as an increment in the carbonyl index supposedly caused by bacterial biofilm biodegradation. Our findings shed light on the ability of our strain B. cereus CGK5 to colonize and use HDPE as a sole carbon source, demonstrating its applicability for future eco-friendly biodegradation processes.

Hydrophobically modified Pd membrane for the efficient purification of hydrogen in light alcohols steam reforming process

The ability to selectively remove H2 from the product has made palladium (Pd) membrane reactor a good choice for steam reforming reaction. However, carbonaceous deposited on the surface of Pd membrane during reaction hindered its industrial application. In order to protect Pd membrane from being poisoned by water and light alcohols, a TS-1/Pd composite membrane was prepared by a facile one-step hydrothermal method combined with silane coupling treatment. The zeolite layer acted as a protective armor by keeping poisonous species away from the Pd bulk, and the silanization process increased the hydrophobicity by reducing the hydroxyl density on the surface of TS-1/Pd composite membrane. After 100 h’s exposure in the steam reforming condition, the percentage of carbon content was only 0.95% for the TS-1/Pd membrane, compared with 13.20% for the pure Pd membrane. The H2 permeability and H2/N2 selectivity of the TS-1/Pd remained constant, while that for pure Pd membrane fell by 50% and 80%, respectively. The significantly improved resistance to carbon deposition provides possibility for the large-scale application of Pd membrane reactor in hydrogen production via steam reforming.

Degradation Behavior of Biodegradable Plastics in Thermophilic Landfill Soil and Wastewater Sludge Conditions

In this study, three common biodegradable plastics, namely, poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV), poly(butylene succinate) (PBS) and poly(butylene adipate-co-terephthalate) (PBAT) were all buried in a mixture of landfill soil and wastewater sludge and incubated under thermophilic (61°C) oxygen-limited conditions. At the end of the 90-day test, the degradation ranking order was PHBV > PBS > PBAT. Only PHBV was completely degraded over the 60 days, while PBS and PBAT displayed 24.04% ± 3.37% and 18.26% ± 3.77% weight loss, respectively. The differences in the degradation and disintegration profiles among these materials were observed. The results showed that PHBV lost its thickness and degraded from the edges of the specimens. Both PBS and PBAT were reduced into small fragile fragments during the degradation process. SEM micrographs revealed that irregular roughness with many holes and cracks was characteristic of PHBV, while slightly smooth surfaces were found on PBS and PBAT. All the materials showed continuous decreases in the thermal stability and the percentage of carbon content in the molecular structures after the degradation test. Fourier transform infrared (FTIR) spectroscopy revealed that the chemical structure of PHBV was changed during the biodegradation test, while both PBS and PBAT were unchanged under the same test conditions. However, the peak for carboxylate ions was found after the degradation of all the samples. Having a deep understanding of the degradability behavior can contribute to the development of biodegradable plastic waste management in the future.

Properties of natural adsorbent prepared from two local Sudanese agricultural wastes mango seeds and date's stones and their uses in removal of contamination from fluid nutrient

BackgroundIn recent years, special attention has been focused on the use of natural adsorbents as an alternative to replace the conventional adsorbents, based on both the environmental and the economical points of view. The study aimed to produce natural absorbent (activated carbon) from two local agricultural wastes: mango seeds (MS) and date stones (DS) and their uses in removal of contamination from fluid nutrient. Chemical properties such as ash content, moisture content, carbon content percentage and percentage of methylene blue reduction of the two samples were investigated.ResultsThe results of study indicated that activated carbon produced from both MS and DS samples have the same pH value of 7 (neutral).The ash content of activated carbon prepared from mango seeds and date’s stones was 9.7 and 9.5%, respectively.Our statistical analysis showed no significant difference (p ≥ 0.05)for ash determinations, while the moisture content of (19.5 and 19.9%) was found for mango seeds and date's stones, respectively. There was no significant difference at p > 0.05 for moisture content of the two samples. A significant difference was observed in carbon contents for mango seeds (61.4%) and date's stones (21.8%) at p ≤ 0.05). There was no significant difference at p > 0.05 for moisture content of the two samples. Statistical analysis showed significance difference (p ≤ 0.05) for carbon determination for both samples. The results also indicated that there was significant correlation between reduction in methylene blue and percentage of activated carbon.ConclusionsActivated carbon produced from MS and DS was found to be very effective in color removal and of acceptable quality in pH, carbon content, ash content, moisture content and solubility.

Radiation induced defects in graphite

The Raman intensity ratio ID/IG for: (a) graphite-rich pencil rods irradiated using x-ray doses up to 20 Gy; (b) a restricted view of the ID/IG response for the same group of media, limited to x-ray doses of no more than 6 Gy; (c1 and c2) an extended group of graphite-rich media irradiated using 60Co gamma-rays; (d) a restricted view of the ID/IG response for a restricted group of the media shown in (c), with 60Co gamma-ray doses limited to no more than 20 Gy; (e) 2B graphite-rich pencil rods irradiated using 6 MeV electrons, and: (f) irradiation of a subset of the media by thermal (0.025 eV) neutrons. The fluctuation of ID/IG with dose for carbon-rich human hair of nominal diameter 60 μm is indicated by the dashed line in (c) and (d). The values in parentheses indicate the percentage carbon content and the surface area-to-volume ratio of samples. The data are a re-organisation of that included in the studies of Abdul Sani et al. (2020, Bradley et al. (2019, 2021), Mat Nawi et al. (2021a,b), and Lam et al. (2021) such as to illustrate three prime dependencies, viz. surface to volume ratio, carbon content, and linear energy transfer, LET. (g) and (h) are combination graphs as indicated in the key to each.

Carbon storage and energy production of Eucalyptus urophylla developed in dryland ecosystems at East Nusa Tenggara

The development of Eucalyptus urophylla in dryland ecosystems plays an important contribution to support climate change mitigation and renewable energy diversification. However, the information about the potential of E. urophylla for carbon reduction and energy production is rarely documented, even though it is necessary as fundamental considerations to determine the best strategy for sustainable natural resources management, primarily in dryland ecosystems. This study aimed to quantify the carbon storage and energy production of E. urophylla established in dryland ecosystems at East Nusa Tenggara. The study site is located in a eucalyptus plantation managed by Timor Tengah Selatan Forest Management Unit. Destructive sampling was conducted on 25 sample trees that were evenly distributed from small to big ones. The percentage of carbon content in every tree component, namely stem, branch, and foliage, was determined using elemental analysis, while the calorific value of each tree component was analyzed using a bomb calorimeter. Carbon storage in each component was calculated by multiplying biomass and the percentage of carbon content, while the energy production was computed by multiplying high heating value and biomass from every tree component. The results found the mean carbon storage of E. urophylla in the study site was 55.51 kg tree-1 with a minimum of 6.34 kg tree-1 and a maximum of 184.76 kg tree-1. The percentage of carbon content in the foliage was lower than other tree components by approximately 34.1%. Interestingly, the calorific value of foliage was relatively higher than stem and branch with around 5,252 kcal kg-1. The energy production of E. urophylla ranged from 252.6 to 7,813.3 MJ tree-1 with an average of 2,357.87 MJ tree-1. According to the results, this study concluded the development of E. urophylla in dryland ecosystems demonstrated a meaningful contribution to carbon absorption and energy production at East Nusa Tenggara.

Classification of coal deposited epoxy micro-nanocomposites by adopting machine learning techniques to LIBS analysis

Epoxy micro-nanocomposite specimens incorporated with 66 wt% of silica micro fillers and 0.7 wt% of ion trapping particles as nano fillers, are coated with four different variants of coal. The conductivity of the coal deposited samples is observed to be in direct correlation with the percentage carbon content present in the coal samples. The epoxy micro-nanocomposite specimens coated with different variants of coals were successfully classified by using Laser induced breakdown spectroscopy (LIBS) assisted by various machine learning techniques. It is noticed that the classification through Logistic regression method (LRM) has reflected a higher training as well as testing accuracy of 100% and 98%, respectively when compared to other machine learning methods.

Mineral Nutrients, Organic Amendment, and Water Impact Decomposition of Biodegradable Containers Under Controlled Conditions

Laboratory studies were conducted to evaluate effect of soil water content, organic soil amendment, and mineral nutrient application on decomposition of three types of biodegradable containers: recycled paper, wood pulp fiber, and coconut coir over 182 days. Soil respiration was assessed through alkaline trap and titration method to determine decomposition of biodegradable containers. Percentage of carbon content remaining in the container material after 182 days was also quantified. Relative to soil water content, recycled paper containers under 40% water holding capacity (WHC) had higher carbon dioxide released than 60%WHC. Carbon analysis indicated that less carbon remained for all container types under 60% than 40%WHC. For recycled paper and coconut coir pots, treatments receiving container and soil amendment had significantly increased soil respiration. Post-experiment carbon analysis revealed less carbon remained in the recycled paper, wood pulp fiber, and coconut coir containers in the absence of organic soil amendment. For coconut coir, the interaction of container × mineral nutrients appeared to increase soil respiration with higher carbon dioxide released under biodegradable container × low mineral nutrient. This study suggests that cultural practices (i.e., irrigation and organic matter amendment) could facilitate degradation for certain biodegradable container types; however, to provide extensive cultural practice recommendations regarding biodegradable containers, more research is needed.

Structural Carbon Allocation and Wood Growth Reflect Climate Variation in Stands of Hybrid White Spruce in Central Interior British Columbia, Canada

Research Highlights: This research presents a novel approach for comparing structural carbon allocation to tree growth and to climate in a dendrochronological analysis. Increasing temperatures reduced the carbon proportion of wood in some cases. Background and Objectives: Our goal was to estimate the structural carbon content of wood within hybrid white spruce (Picea glauca (Moench) × engelmannii (Parry) grown in British Columbia, Canada, and compare the percent carbon content to wood properties and climate conditions of the region. Specific objectives included: (i) the determination of average incremental percent carbon, ring widths (RW), earlywood (EW) and latewood (LW) widths, cell wall thickness, and density over time; (ii) the determination of differences between percent carbon in individual forest stands and between regions; and (iii) the evaluation of the relationships between percent carbon and climate variation over time. Methods: Trees were sampled from twelve sites in northern British Columbia. Wood cores were analyzed with standard dendrochronology techniques and SilviScan analysis. Percent structural carbon was determined using acetone extraction and elemental analysis for 5 year increments. Individual chronologies of wood properties and percent carbon, and chronologies grouped by region were compared by difference of means. Temperature and precipitation values from the regions were compared to the carbon chronologies using correlation, regression, and visual interpretation. Results: Significant differences were found between the percent structural carbon of wood in individual natural and planted stands; none in regional aggregates. Some significant relationships were found between percent carbon, RW, EW, LW, and the cell wall thickness and density values. Percent carbon accumulation in planted stands and natural stands was found in some cases to correlate with increasing temperatures. Natural stand percent carbon values truncated to the last 30 years of growth was shown as more sensitive to climate variation compared to the entire time series. Conclusions: Differences between the stands in terms of structural carbon proportion vary by site-specific climate characteristics in areas of central interior British Columbia. Wood properties can be good indicators of variation in sequestered carbon in some stands. Carbon accumulation was reduced with increasing temperatures; however, warmer late-season conditions appear to enhance growth and carbon accumulation.

Investigation on Effect of Material Compositions on Machinability of Carbon Steels

Steels are basically classified based on their carbon contents. In view of this, the processing of steels is greatly affected by their composition, particularly their carbon content. This paper reports on the machinability of three different steels with varying carbon contents. The steel samples were sourced from Owode metal market in Ilorin, Kwara State and their percentage compositional analysis was carried out at Universal Steels Limited, Lagos. The steel samples were classified into high, medium and low carbon steels based on their percentage carbon content. The machining condition was wet and the machining parameters used were depth of cut (0.2 – 0.6 mm), feed rate (0.05 – 0.15 mm/rev), and cutting speed (100 - 150 rpm). The experimental runs were designed using Taguchi orthogonal array of Minitab version 16 and the cutting temperature was monitored with a digital thermometer and k-type thermocouple wires. The experimental results were analysed using Minitab 18 with a focus on percentage contribution of various factors affecting surface roughness, chip morphology, cutting temperature and material removal rate. Results show that surface finish is highest in low carbon steel and lowest in high carbon steel. The responses show that machinability of the steel improved with a reduction in carbon content.

Utilization of oil palm fronds for bio-oil and bio-char production using hydrothermal liquefaction technology

Hydrothermal liquefaction technology carried out on local Malaysian oil palm fronds (OPF) in a batch autoclave reactor to produce solid bio-char as well as liquid bio-oil is reported in this study. The parameters taken in consideration for study encapsulated variable reaction temperature (160–260 °C) and reaction times (20–100 min). Observations showed that the bio-oil yield percentage increased from 27.3% at 160 °C to 41.9% at 260 °C, whereas bio-char yield percentage decreased from 65.2% at 160 °C to 43.2% at 260 °C. Similarly, higher reaction time also produces higher yield bio-oil percentage and lower bio-char yield percentage. The characterization results showed that the combustion properties of bio-char and bio-oil were improved after hydrothermal liquefaction due to decrease in percentage of oxygen of bio-oil and bio-char and an increase in percentage of carbon content. The carbon percentage increased from 42.73% for OPF to 59.42% and 60.47% for bio-char and bio-oil, respectively. Whereas, the percentage of oxygen decreased from 52.51 for OPF to 36.30% and 35.61 for bio-char and bio-oil. The main chemical compounds identified in bio-oil by GC-MS were phenolic compounds and their derivatives, alcohols, ketones, and esters.

An upgraded bio-oil produced from sugarcane bagasse via the use of HZSM-5 zeolite catalyst

The pyrolysis upgrading of bio-oil from sugarcane bagasse (SB) using ZSM-5 zeolite catalyst was carried out in a fixed bed reactor to determine the effects of heating rate, temperature, and catalyst/biomass ratio on yield of bio-oil and their chemical compositions. Proximate analysis indicated that SB has 13.2% moisture content. The ultimate analysis carried out established that the percentage of carbon content is higher (48.2%) than oxygen content (44%) while the fibre content analysis showed 26.4% lignin, 33.3% cellulose, 30.1% hemicellulose. The heating rate, temperature and catalyst/biomass ratio were varied in the range of 10–50°C/min, 400–600°C and 0.05–0.25 respectively. The non-catalytic pyrolysis gave the maximum percentage yield (45.67wt%) of bio-oil at a pyrolysis temperature of 600°C, heating rate of 50°C/min, sweeping gas flow rate of 40mL/min and the catalytic pyrolysis gave 40.83wt% of bio-oil at the same conditions. The FT-IR spectra showed that the non-catalytic bio-oil is dominated by oxygenated compounds (acids, ketones, aldehydes, alcohols), while the catalytic bio-oil had preponderances of desirable compounds (alkanes, alkenes, aromatics, phenols). The chemical composition of the bio-oils was analyzed using GC–MS, which revealed that the quality of the bio-oil has been improved using HZSM-5 catalyzed pyrolysis.

Comparative Assessment of Locally Produced Reinforcing Steel Bars for Structural Purposes: 12 mm Steel Bars from Delta Steel Company (DSC), Warri-Nigeria as a Case Study

Some relevant Chemical and Mechanical Properties of 12 mm ribbed steel bars from three different Heat Numbers of Delta Steel Company (DSC), Warri were investigated. The results of the chemical analysis show that the three samples have percent carbon content higher than the 0.25%C recommended by BS 4449 of 1997 and 0.30% recommended by ASTM A706. The results show that sample 1 has 0.32%C, sample 2 has 0.38%C and sample 3 has 0.31%C. This high percent carbon must have contributed to the high tensile strength values obtained. The values of the percentage elongation at fracture for all the tested steel samples surpassed the 12% recommended by BS and 10% recommended by ASTM A706. The results of the hardness test show 26.31 HRC for sample 1, 26.50 HRC for sample 2, and 26.40 HRC for sample 3. These values are higher than 13.48 HRC and 23.85 HRC estimated for BS4449, 1997 and ASTM A706 respectively. This means that most steel bars used for construction projects in Nigeria have higher mechanical property values than the standards, hence satisfy the required quality for construction.

Degradation of Poly (lactic acid) under Simulated Landfill Conditions

In this study, the physical and chemical properties change of poly (lactic acid) after being buriedin the mixture of soil and sludge under thermophilic (61 °C) oxygen limited conditions were investigated using various analytical techniques. The environmental factors under these setting conditions and microbial activities accelerated the degradation process of PLA. Under tested conditions, PLA lost their weight about 90% at the 90 days burial period. During the degradation process, PLA samples were continuously broken to small fragile fragments and showed the size less than 1 mm at the end of the degradation test. The change of the surface morphology was revealed by Scanning Electron Microscopy (SEM). Many pores, cracks and irregular roughness were presented on the PLA surface. Thermal decomposition was decreased from 387.8 °C to 289.2 °C. The percentage of carbon content in molecular structure decreased from 49.46% to 45.42%. In addition, the Fourier transformed infrared spectroscopy (FTIR) revealed the change of ester bonds. This study can be used to develop the PLA waste management process.

Co-digestion of Livestock Wastes for Biogas Production

Co-digestion of cow dung, poultry dropping and pig manure was carried out in batch digesters at mesophilic temperature for twenty-eight days to determine the biogas generating potentials. The wastes were also digested individually for the same period and under the same conditions. The physicochemical and bacteriological characteristics were determined using standard techniques. The range of PH, temperature, percentage moisture content, percentage chemical oxygen demand, percentage carbon content, and the bacterial loads of the wastes slurries before digestion were 6.4- 6.8, 28.0℃ - 29.0℃, 80.0 - 80.2, 9.2 - 11.0, 32.0-46.0 and 3.7 x 106cfu/ml -6.2 x 106 cfu/ml respectively and 6.6-7.5, 27.6℃ -28.5℃, 80.2-91.6, 7.0-9.4, 35.0-58.0 and 1.6 x 106 cfu/ml-5.2 x 106 cfu/ml respectively at the end of digestion. The biogas yield from the digestion of the cow dung, poultry dropping and pig manure individually were 185ml, 220ml and 170ml respectively while the co-digestion of the substrates yielded more biogas. The cumulative biogas yield from the digestion was 2780ml. The slurry containing 48g: 144g: 48g of cow dung, poultry dropping and pig manure gave the highest biogas yield. This study showed that though the digestion of a single livestock waste can yield some biogas, co-digestion of such wastes has the potential to generate more biogas.