Reduction In Carbon Content Research Articles

Efficient photocatalytic degradation of emerging pollutants by green synthesized Prussian blue analogue nanocomposite

AbstractWorldwide consumption, toxicity, and bioaccumulation of paracetamol (PCM) and atenolol (ATL) has drawn attention of researchers over last decades. A small portion of these drugs is absorbed by human body and rest of them is excreted through urine and feces to the environment (water bodies and soil) which might result in negative impacts. Nanocomposite of chromium oxide coupled with zinc hexacyanocobaltates (Cr2O3@ZnHCC) was synthesized by a green‐method using Sapindus mukorossi seed‐extract for the removal of targeted drugs. Microscopic and spectroscopic analysis of Cr2O3@ZnHCC showed uniformly incorporated prisms into cubic structure having ~75 nm particle size. Well‐characterized Cr2O3@ZnHCC and individuals (Cr2O3 & ZnHCC) were utilized for the degradation of PCM and ATL under direct sunlight and dark conditions. Highest degradation of targeted drugs (91%–94%) resulted at 20 mg L−1 concentration of pollutant, 25 mg of catalyst dose, and pH ~ 7 under daylight exposure (5 h). First‐order kinetics followed with a high adsorption capacity, Xm (13.4–14.5 mg g−1) value was obtained to confirm the strong binding with the pollutants. Moreover, Cr2O3@ZnHCC substantially suppressed the half‐life of targeted drugs (PCM: 0.6 h; ATL: 2.9 h) and converted them into safer‐small metabolites as confirmed by liquid chromatography‐mass‐spectrometry analysis, and the reduction of carbon content was confirmed by total organic carbon analysis. The charge separation mechanism was assisted by UV reflectance and photoluminescence data. The synthesized green‐nano photocatalyst displayed high reproducibility (up to 10th cycle), sensitivity, and stability during the degradation process which makes this a suitable candidate for industrial applications.

Association of atomic clusters and free volume with the viscosity of Fe-C melts

A comprehensive investigation on liquid structure and viscosity of Fe-C melts were performed. The result shows that there is actually a medium-range ordered cluster structure in molten iron, which is unstable and will change due to the existence of free volume. Carbon atoms exist in an ordered structure inside the melt, while iron atoms have three coordination states. The reduction of carbon content and the increase of temperature contribute to a low viscosity of molten iron. Meanwhile, the number and size of clusters in the Fe-C melt increase accordingly, but the mechanisms affected by temperature and composition are different.

Polyvinyl pyrrolidone (PVP) as an efficient and biocompatible binder for metal alloy processing: A case study with Ti‐20Zr‐11Nb‐3Sn

AbstractTitanium (Ti) being a lightweight, biocompatible, and strong metal, immense attention is being paid to develop Ti‐based different low‐cost and efficient biomedical implants by employing additive manufacturing (AM) or 3D printing. Binder having abundant binding efficacy binds the alloying metal powders and maintains their stoichiometry and close attachment. However, in the case of Ti‐alloy, the Ti, or other alloying metals, e.g., zirconium (Zr), because of their high reactivity with ambient moisture and oxygen, needs to be stabilized before the alloy formation. In this work, instead of using various non‐biocompatible thermoplastic and semi‐crystalline polymers responsible for causing stress‐induced defects in the final structure, the efficacy of a biocompatible amorphous polymer (i.e., polyvinyl pyrrolidone [PVP]) as a binder towards developing the Ti‐alloy has been examined. PVP‐bound alloying metal powders were found to be stable for 30 days (as per the XRD analysis) and exhibited a nearly similar composition to the experimental formula. Thermal debinding was examined for two temperatures, 600 and 1000°C, and compared with the help of SEM and XRD analyses. The better debinding (i.e., reduction of carbon content as per the EDX analysis) was found for the 1000°C debinding temperature.

Experimental investigation on NO emission and burnout characteristics of high-temperature char under the improved preheating combustion technology

In order to avoid the formation of NO from the nitrogen-containing pyrolysis components in the main combustion zone under preheating combustion technology, an improved preheating combustion technology was proposed. A two-stage drop-tube furnace was built to study the NO emission and combustion characteristics of high-temperature char (HTC) under the improved preheating combustion technology. The char was first heated to the initial pyrolysis temperature(600℃,800℃ and 1000℃) in the upper furnace under the atmosphere of nitrogen, before being burned in the second furnace. The influence of important operating parameters such as HTC temperature(600℃,800℃ and 1000℃), combustion temperature (1200℃,1300℃ and 1400℃)and excess air ratio (0.6 ∼ 1.4)were analyzed. The results show that raising the HTC temperature helps to reduce NO emissions. The maximum NO reduction efficiency is 21.1 % when the excess air ratio(α) = 1.0, which differs from the reported literature results of room-temperature char (RTC). In HTC, there is no absolute correlation observed between the BET area and NO reduction. The release of C and N is altered by pre-ignition of char at HTC; additionally, the evolution of nitrogen functional groups during the pyrolysis process is more key influencing factors. The stoichiometric ratio has a considerable influence on the effects of combustion temperature on NO emission. When there is a lack of oxygen, NOx emissions decrease as the temperature rises, whereas under oxygen-rich situations the converse is true. With the increase in HTC temperature from 600 °C to 1000 °C, the critical excess air ratio steadily increases from 0.75 to 0.85. The carbon concentration of fly ash can be reduced by increasing both the HTC and the combustion temperature. The largest reduction in carbon content in fly ash is 28.6 % at α = 1.0.

Variation of White Spruce Carbon Content with Age, Height, Social Classes and Silvicultural Management

The accuracy and precision with which carbon amounts have been accounted for in forests have been questioned. As countries seek to comply with agreements to reduce global warming and industries seek to maximize bioenergy potential, this matter has increased international concern. White spruce (Picea glauca (Moench) Voss) stand density management trials in the Petawawa Research Forest, Ontario, Canada, were sampled to evaluate carbon concentration variation within trees and plots of differing stand density. Sample-drying methodologies were also tested to compare freeze-dried carbon (FDC) and oven-dried carbon (ODC) measurements. The average FDC was 51.80 ± 1.19%, and the corrected freeze-dried carbon content (FDCCOR) was 51.76 ± 1.33%. The average ODC was 49.10 ± 0.92%, and the average volatile carbon fraction (Cvol) was 2.67 ± 1.71%. FDC was higher than ODC (mean of the differences = 2.52) and generally more variable. ODC significantly decreased radially and longitudinally. FDC was significantly affected by thinning, where heavy treatments resulted in the highest FDC amounts compared to medium, light, and control treatments. In addition to reducing carbon content (CC), drying influences wood CC in many ways that are still to be elucidated. The results of this study suggest that ODC should continue to be used within the bioenergy industry, while FDC must become the preferred standard for carbon accounting protocols.

Analysis of a High-Strength Steel SMAW Database

Recently, Dr. Glyn M. Evans posted a large shielded metal arc (SMA) weld metal (WM) database on the ResearchGate website (researchgate.net). This database contains more than 950 WM compositions, along with their respective WM tensile and Charpy V-notch (CVN) impact properties. In particular, the CVN impact properties list the test temperatures that achieved 28 and 100 J impact energy for each WM composition. While the availability of this SMA WM database is a valuable and rare gift to the welding community, how could the welding community analyze this database to gain valuable insights? This paper utilizes a constraints-based model (CBM) as a simple and effective framework to organize and analyze this very large Fe-C-Mn SMA WM database. A CBM is built on the metallurgical principle that one needs to lower relevant solid-state phase transformation (i.e., austenite decomposition) temperatures to improve WM strength and fracture toughness while simultaneously reducing carbon content and Yurioka’s carbon equivalent number (CEN) to improve the weldability of high-strength steels. To this end, a CBM identifies and simultaneously solves several statistical (regression) equations that relate the chemical composition of high-strength steel WM with Yurioka’s CEN and selected solid-state phase transformation temperatures related to austenite decomposition. The results of the current effort demonstrate that the analysis of Evans’s shielded metal arc welding database using a CBM as a framework reaffirms that controlling carbon content, the value of the CEN, and calculated solid-state phase transformation temperatures, particularly the difference between the calculated Bs (bainite-start) and Ms (martensite-start) temperatures, is critical to developing and identifying high-performance, high-strength steel welding electrodes. A dual approach that manipulates the contents of principal alloy elements such as C, Mn, Ni, Cr, Mo, and Cu, and adds controlled amounts of Ti, B, Al, O, and N, appears to offer the best means to lower relevant solid-state phase transformation temperatures to produce high-strength and high-toughness WMs.

Effects of casting parameters and impurity concentrations on as-cast U–10Mo

This work investigates the effects of casting parameter changes on as-cast uranium-10 wt% molybdenum (U–10Mo) alloys on a 1–2 kg scale. A commercial tilt-pour vacuum induction melting system was utilized to study the effects of casting atmosphere, total heating time, hold time at maximum temperature, mold temperature, and crucible type on as-cast U–10Mo impurities and dendrite size. Fourteen plates of differing geometry were cast and analyzed for carbon, oxygen, hydrogen, and nitrogen impurities, as well as molybdenum content. Primary dendrite lengths (PDL) in the microstructure are quantified. A statistical evaluation was performed to identify key carbon and oxygen relationships with operating parameters, impurities, and PDL. Additional factors investigated include crucible material, time at maximum temperature, and total heating time. Zirconia crucibles reduced carbon content on average by 35 % over traditional graphite crucibles. There was statistically relevant associations between carbon and oxygen content, oxygen content and maximum temperature hold time, mold temperature and PDL, and between PDL, maximum temperature hold time, and mold temperature.

Study on Optimum Steam to Oxygen Blowing Ratio for Enhanced Chromium Recovery from Ferrochromium in Creusot Loire Uddeholm Converter

Currently, the yield of metallic chromium from ferrochromium (FeCr) in Creusot Loire Uddeholm converter (hereafter abbreviated as CLU), is below optimum, owing to poor oxidation of FeCr feed. Consequently, oxygen not only reacts with carbon but chromium too, thereby causing a reduction in yield of metallic chromium. Howbeit, the focus of this research was to determine the optimum steam to oxygen blow ratio for enhanced chromium recovery from CLU converter. The focus was achieved by determining best slag chemistry for recovery of metallic chromium and carbon level switchover for best blowing ratio. Both feed and outputs from CLU process were analyzed using the ICP AES for elemental contents. The results obtained showed an increase in chromium content by16%, and a reduction in carbon content by 71%, while change in iron content was approximately 0% after refining, at a slag basicity of 1.1 to 1.4 and slag chemistry of CaO (32.5 wt%), MgO (11.5 wt%) and SiO2 (38.7 wt%). In conclusion, the best chromium recovery at lowest carbon content was achieved at an oxygen to steam blowing ratio of 6 to 10 and critical carbon content switchover point of 2.1 wt%.

Self-assembly synthesis of dumbbell-like MnPO4·H2O hierarchical particle and its application in LiMnPO4/C cathode materials

The large-scale and efficient synthesis of MnPO4·H2O is an urgent problem to be solved. In this paper, self-assembled dumbbell-shaped MnPO4·H2O particles were successfully synthesized just using KMnO4 and commercial concentrated H3PO4, and then employed as the precursor to prepare LiMnPO4/C composites. The XRD, SEM, TEM, and electrochemical performance tests were used to investigate MnPO4·H2O and the corresponding LiMnPO4/C. The formation mechanism of MnPO4·H2O was discussed. The results showed that temperature and water content have a significant effect on the yield, purity, and morphology of MnPO4·H2O. The synthesized LiMnPO4/C with reduced carbon content at 650 °C delivered a discharge capacity of 109.3 mA h g-1 at 1 C and 104.3 mA h g-1 at 2 C. This green and efficient synthesis method of MnPO4·H2O provides a new idea for the large-scale preparation of LiMnPO4/C cathode materials.

ОБОСНОВАНИЕ КОРРЕКТИРУЮЩИХ ВОЗДЕЙСТВИЙ, КОМПЕНСИРУЮЩИХ ПОНИЖЕННОЕ СОДЕРЖАНИЕ УГЛЕРОДА В СТАЛИ ПРИ ПРОИЗВОДСТВЕ ХОЛОДНОКАТАНОГО ЛИСТОВОГО ПРОКАТА ДЛЯ ШТАМПОВКИ

The relevance of the work. There are situations in the practice of metallurgical production when steel melting with a chemical composition intended to complete the determined order is reassigned to the production of rolled metal from another steel grade. With the formal accordance of chemical composition of melted steel to the requirements for a different steel grade, crucial control parameters of process that are traditionally used for a new grade of steel, may turn out to be inappropriate for structural and phase transformations in steel with real chemical composition. To prevent the re-lease of non-conforming products is necessary to develop and apply operational corrective actions. The purpose of the work is selection and rationale of operational corrective actions in the production of cold rolled sheet products of quality classes CQ, DQ and DDQ of mild quality steel to compensate for the reduced carbon content in meltings assigned to complete the respective orders. Microscopy methods were used to study the structure and phase composition of steel with a carbon content of 0,008 – 0,04 % in hot-rolled and cold-rolled states. Data on the mechanical properties of hot-rolled and cold-rolled steel were obtained by standardized tensile test methods. Based on the test results, re-liable multiple approximations of influence of control characteristics of the technology on properties of cold-rolled steel were constructed, which were subsequently used in optimization of thickness of semi finished rolled product for cold rolling as a compensating effect at the fluctuations of carbon content within the above limits. The novelty of the work lies in the identification and rationale of corrective actions for a technological system in which cold rolling is carried out on a continuous four-stand mill with roll feed. The results of the work consist in determining the temperature of the end of rolling and the increment of the thickness of the semi finished rolled product as operation-al compensating effects at assigning steel meltings with a low carbon content for rolling into a tech-nological system with a continuous four-stand mill with roll feed. The practical significance of the work is to prevent the yield of non-conforming products at using the proposed solution in the pro-duction of cold-rolled steel of quality classes CQ, DQ and DDQ 0,6–2,0 mm thick.

Cadmium biosorption and biomass production by two freshwater microalgae Scenedesmus acutus and Chlorella pyrenoidosa: An integrated approach

Cadmium (Cd) contamination in different water bodies is a matter of serious concern, as it can cause biomagnification in our food chain up to several trophic levels. In this study, Cd toxicity was investigated in the micro-algae Chlorella pyrenoidosa and Scenedesmus acutus exposed to various concentrations of Cd for 96 h. The inhibitory and toxic effects of Cd2+ on growth and photosynthetic parameters of algae were demonstrated. The bioremediation potentials of these algae were investigated and bioremoval mechanisms were confirmed using qualitative electron microscopic assay such as scanning/transmission electron microscope (S/TEM). The photochemical quenching (Fv/Fm), quantum yield (YII), relative electron transfer rate (rETR) and non-photochemical quenching (NPQ) were inhibited significantly and reduced by ≥ 50% of the control at MIC 50 values. The C. pyrenoidosa and S. acutus biomass have shown 30% and 20% reduction in carbon content and 10% and 12% reduction in nitrogen content at MIC50 values of Cd2+ treatment, respectively. During bioremoval studies, C. pyrenoidosa and S. acutus have shown 45.45% and 57.14% Cd2+ removal of Cd2+ from initial concentration of 1.5 ppm. Out of total cadmium removal C. pyrenoidosa was reported 3% bioaccumulation and 97% biosorption. Whereas S. acutus showed 1.5% accumulation and 98.5% biosorption. The S/TEM images showed the surface accumulation and bioaccumulation of cadmium inside the cytoplasm, vacuoles, and chloroplast. Thus cultivating C. pyrenoidosa and S. acutus would be beneficial in Cd2+ contaminated water bodies as they serve the dual purpose by Cd remediation and algal biomass production.

A Numerical Analysis of the Effects of Supercritical CO2 Injection on CO2 Storage Capacities of Geological Formations

One of the most promising means of reducing carbon content in the atmosphere, which is aimed at tackling the threats of global warming, is injecting carbon dioxide (CO2) into deep saline aquifers (DSAs). Keeping this in mind, this research aims to investigate the effects of various injection schemes/scenarios and aquifer characteristics with a particular view to enhance the current understanding of the key permanent sequestration mechanisms, namely, residual and solubility trapping of CO2. The paper also aims to study the influence of different injection scenarios and flow conditions on the CO2 storage capacity and efficiency of DSAs. Furthermore, a specific term of the permanent capacity and efficiency factor of CO2 immobilization in sedimentary formations is introduced to help facilitate the above analysis. Analyses for the effects of various injection schemes/scenarios and aquifer characteristics on enhancing the key permanent sequestration mechanisms is examined through a series of numerical simulations employed on 3D homogeneous and heterogeneous aquifers based on the geological settings for Sleipner Vest Field, which is located in the Norwegian part of the North Sea. The simulation results highlight the effects of heterogeneity, permeability isotropy, injection orientation and methodology, and domain-grid refinement on the capillary pressure–saturation relationships and the amounts of integrated CO2 throughout the timeline of the simulation via different trapping mechanisms (solubility, residual and structural) and accordingly affect the efficiency of CO2 sequestration. The results have shown that heterogeneity increases the residual trapping of CO2, while homogeneous formations promote more CO2 dissolution because fluid flows faster in homogeneous porous media, inducing more contact with fresh brine, leading to higher dissolution rates of CO2 compared to those in heterogeneous porous medium, which limits fluid seepage. Cyclic injection has been shown to have more influence on heterogenous domains as it increases the capillary pressure, which forces more CO2 into smaller-sized pores to be trapped and exposed to dissolution in the brine at later stages of storage. Storage efficiency increases proportionally with the vertical-to-horizontal permeability ratio of geological formations because higher ratios facilitate the further extent of the gas plume and increases the solubility trapping of the integrated gas. The developed methodology and the presented results are expected to play key roles in providing further insights for assessing the feasibility of various geological formations for CO2 storage.

Production of ultrafine-grained spherical β-WC-W2C-Co microparticles by electro discharge erosion of WC-15Co alloy in glycerol and their solutions

The present work is devoted to the study of the production of ultrafine-grained (UFG) spherical microparticles by electro discharge erosion (EDE) of the WC-15Co cemented carbide in glycerol, distilled water, and their solutions. Energy costs, productivity, particle size distribution, and morphological and chemical compositions of the obtained powders were studied. It was found that energy cost is reduced by 2.2 times when glycerol was used instead of water. The use of water reduces carbon content from 5.2% to 1.4%. The use of glycerol and its aqueous solutions reduces carbon loss and increases its content in the obtained powders from 3.2% to 6.1%. During SE, cobalt, carbon, and tungsten evaporate from spherical particles and crystallize in the form of ultrafine particles, which subsequently remain in suspension after sedimentation of spherical particles. Mass fractions of sedimented spherical particle fractions ranged from 75% to 82%. Cobalt and carbon content in the spherical particles obtained in glycerol decrease from 15% to 10% and from 5.2% t to 3.1% respectively. The particles consist of rounded carbide grains (β-WC and W2C) with a diameter of up to 500 nm, the space between which is filled with cobalt. Microhardness of the particles increased from 12.1 GPa (initial alloy) to 15.6 (EDE in water)—23.7 GPa (EDE in glycerol).

Effects of feedstock biopolymer compositions on the physiochemical characteristics of dissolved black carbon from lignocellulose-based biochar

Dissolved black carbon (DBC) is becoming increasingly concerned by researchers due to its unique environmental behavior. However, understanding of the influence mechanism of biopolymer compositions of cellulose (CEL), hemicellulose (HEM) and lignin (LIG) on the formation and physiochemical characteristics of DBC from lignocellulose-based biochar is limited. This study therefore examined the formation of DBCs derived from the biopolymer compositions, corn straw (CS), corncob (CC), bamboo sawdust (BS) and pinewood sawdust (PS) under the heat treatment temperatures (HTTs) of 300–500 °C. Zeta potential and hydrodynamic diameters (Dh) of DBCs produced under 300 °C were further investigated. DBC formation may be closely associated with the HTT-dependent heterogeneities of biopolymer compositions, in which significant effects of CEL and HEM charring on physiochemical properties of DBCs were identified under the HTT of 300 and 400 °C, while the formation of DBCs was closely related to LIG and its proportions in biomass under high HTT (>500 °C). On the rise of the HTT, the carbonaceous structures of biopolymer compositions were reorganized and converted to graphitic structures in biochar accompanied by the large decomposition or carbonization of CEL and HEM, leading to the reduced carbon content, surface functional groups, aromaticity and molecular weight of DBCs, as well as the decrease of protein-like and relative increase of fulvic-like fluorescent substances in most DBCs. LIG in biomass may facilitate the migration of DBCs due to abundant surface negative charges and the formation of low Dh. This study offered new insights into our understanding of influencing mechanisms of biopolymer compositions on the characteristic of DBCs under different HTTs.

Experimental investigations on performance, emission and combustion characteristics of Diesel-Hydrogen and Diesel-HHO gas in a Dual fuel CI engine

Stringent emission norms being followed throughout the world increases the demand for clean and green fuels. Gaseous fuels like compressed natural gas (CNG), liquefied petroleum gas (LPG) and hydrogen are promising alternatives to conventional diesel and gasoline. The use of hydrogen in the IC engine has gained interest among the researchers as it can be easily produced from water through electrolysis. Electrolysis of water produces stoichiometric mixture of hydrogen and oxygen in the ratio of 2:1. This study investigates the performance and emission characters of introducing hydrogen and HHO gas in the inlet manifold of a compression ignition engine in dual fuel mode. Experiments were conducted at 5 different torque conditions where hydrogen and HHO gases are supplied at the flow rate of 6, 12, 18, 24, 30 and 36 LPM along with air in the inlet manifold. The HHO gas was synthesized using stored hydrogen and oxygen in the ratio of 2:1. The performance and emission characteristics were noted for all the conditions. The introduction of hydrogen and HHO gas has reduced the diesel energy share ratio by 86% and 70% respectively at no torque condition.HC emission was found to be decreased at high torque condition when compared to neat diesel operation. Significant increase in NOx emission was noted with increase in gases substitution and torque. CO2 and smoke emissions showed positively decreasing trend as the gas percentage increases, due to reduction in carbon content of the fuel mixture. The cylinder pressure reduced with increase in the flow rate of gases. Combustion duration increases with increase in flow rate as well as increase in torque. It was noted that Brake Thermal Efficiency (BTE) reduced for all operating conditions except at 6 LPM of HHO gas addition in the combustion chamber.

Evaluation of Elemental and Chemical Compositions of Some Fuelwood Species for Energy Value

Fuelwood species are a crucial part of the ecosystem; they provide energy for cooking, heating, and lightening for both domestic and industrial uses. As a result of their value, there is a need for frequent evaluation of elemental and chemical compositions for management and conservation purposes. Since fuelwood is the most common and cheapest source of energy in both rural and urban areas in northern Nigeria, the study area is facing serious challenges due to indiscriminate felling of trees for energy use, irrespective of species quality for combustion. Therefore, ten fuelwood species were selected for this study. The selected trees were harvested at Dbh level, replicated three times. Four fuel materials were obtained from each tree sample; these include wood without bark (100% wood sample), wood with 5% bark inclusion, wood with 10% bark inclusion, and whole bark samples and they were evaluated for their inherent elemental and chemical compositions by employing ASTM and TAPPI methods. The results showed that there were significant differences in the tree species and fuel material types obtained from all the ten fuelwood species used. The results of carbon content ranges from 49.54% in A. sieberiana to 50.98% in A. leiocarpus. Meanwhile, the addition of 5% and 10% bark reduces carbon content of wood by 1.25% and 2.74%, respectively. Nitrogen content ranged from 0.31% in A. leiocarpus to 1.00% in A. sieberiana. Among the fuel materials used, isolated bark contained approximately 0.45% nitrogen content compared with wood without bark. Among the tree species, hydrogen content ranged from 3.99% in P. reticulatum to 4.66% in C. arereh. The variation in sulphur contents ranged from 0.24% in C. arereh to 0.93% in A. sieberiana. Lignin content ranged from 10.68% in A. sieberiana to 25.39% in A. leiocarpu and extractive content values ranged from 7.31% in A. leiocarpus to 19.33% in P. reticulatum. Meanwhile, the fuelwood species observed in this study with higher percentage of carbon, hydrogen, and lignin and lower nitrogen and sulphur and extractive content possessed quality fuel value and thereby were encouraged to be incorporated in fuelwood plantation establishment programs (A. leiocarpus, C. molle, C. arereh, and B. aegyptiaca). Lower energy fuelwood species should be allowed for environmental amelioration and carbon sequestration. However, bark contents should be removed for better heating and low ash production during combustion.

Design Features and Performance Evaluation of Natural-Draft, Continuous Operation Gasifier Cookstove

Biomass cookstoves are used as a common source of heating and cooking in developing countries with most improved cookstove design focusing on developing efficiency in thermal conversion of fuels and safer operation than open flame fires. A top-lit-up-draft (TLUD) cookstove utilizes a gasification process similar to pyrolysis where the solid biomass fuels are heated within a oxygen-limited environment and the syngas are burned which reduces carbon content and particulate matter being introduced into the air. The new continuous-operation design is described to have features for: (1) safe addition of solid fuels during combustion of syngas, (2) removal of biochar at the primary air inlet to manage gasification location, and (3) temperature control of the cooksurface through adjustable exhaust paths. The designed cookstove is found to have a diameter to height ratio 0.42-0.47 in order to offer the cleanest burning of the biofuel. The cooking surface is experimentally studied and the thermal gradient is found for compressed wood pellets. Tracking of the coal-bed is studied as a function of time in order to better understand when additional fuel should be added to ensure constant cooking temperature and operation. Numerous exhaust paths explore the cookstove user’s ability to control the temperature contour of the cooksurface.

Design and preliminary characterization of a novel carbide-free 9Cr-ODS martensitic steel

A novel 9Cr-ODS martensitic steel was designed for application in the advanced fusion reactors by reducing carbon content to an extremely low level to avoid the precipitation of M23C6 carbides and increasing manganese content to promote the martensite formation. The preliminary investigation was carried out by means of thermodynamics calculation, phase transformation measurement, microstructural observation and mechanical property testing. The results showed that the desired tempered martensitic structure and elimination of unstable M23C6 around grain/subgrain boundaries were achieved successfully in the fabricated steel with a final composition of Fe-9.25Cr-1.02W-1.05Mn-0.27Y2O3-0.012C (in wt%). Characterized by a homogeneous distribution of nano-size yttrium oxides with an ultrahigh density, absence of coarse M23C6, fine grains with high density dislocations, the designed 9Cr-ODS steel exhibited a relative good tensile properties after normalization and tempering treatments. Due to the slight decline of austenite temperatures (Ac1 and Ac3), a tempering temperature higher than 800 ℃ should be avoided.

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.

Renewable Energy and Energy Security in Malaysia

Robust economic growth, increasing population and personal consumption are the main drivers for the rapid increase of energy demand in Malaysia. Increasing demand has compounded the issue of national energy security due over-dependence on fossil fuel, depleting indigenous domestic conventional energy resources which in turns has increased the country’s energy import dependence. In order to improve its energy security, Malaysia has seriously embarked on a renewable energy journey. Many initiatives on renewable energy have been introduced in the past decade. These strategies have resulted in the exploding growth of renewable energy deployment in Malaysia. Therefore, this study investigated the impact of renewable energy deployment on energy security. Secondary data was used to calculate the energy security indicators. The study also compared the results of applying different energy security indicators namely Availability, Applicability, Affordability and Acceptability dimension of energy resources. The evaluation shows that Malaysia will experience improvement in Energy Security, particularly on Availability, Affordability and Acceptability dimensions of energy security. This study suggests that energy security level could be further enhance by efficient utilization of energy, reducing carbon content of energy and facilitating low-carbon industries.