Effect of case hardening on the wear and hardness properties of medium carbon steel for bone crushing application.

The majority of wear-related problems are connected to crushing machines because hammer failure frequently causes machine failure which eventually leads to machine downtime. Therefore, improving the reliability of crushing materials is necessary for effective production. This research investigation focused on the development of crushing material with appropriate strength properties that can function in critical, impact-prone, corrosive, and abrasive conditions. The current study used palm kernel shell, coconut shell, and sawdust powder as the media for medium carbon steel in order to valorize the agro waste. Carburising media PKS-composition, CS-composition, and SD-composition were changed to 40%: 30%: 30%, PKS-composition 100%, CS-composition 100%, and SD-composition 100%. The process was carried out in 1 h (60 mims), 1 h:30 min (90 min), 2 h (120 min), 2 h:30 (150 min), and 3 h (180 min) soak period with varied carburising temperatures of 900, 950, 1000, and 1050 °C. However, several characterisation and mechanical tests were carried out using an optical microscope, a spark spectrometer, a scanning electron microscope coupled with an energy dispersive spectrometer, wear tester to explore their microstructural features. Vicker's hardness tester, sliding wear tester, and a thermal gravimetric analysis testing machine were also employed. In order to establish reasons for failure other than the cyclic loading on the materials, the results were compared with the properties of as-received un-failed, and carburised medium carbon steel. The results of carburisation show that PKS penetrates carbon at a rate that is noticeably higher than that of other materials at various temperatures and times, indicating that carbon diffuses deeply into the material. Hence, this enhances the wear resistance, and sample's hardness number but decreased its impact toughness respectively.

On the analyses of carbon atom diffused into grey cast iron during carburisation process.

The study employed Fick's second law of diffusion to discover some unknown aspect of carbon diffusion in grey cast iron during carburisation process. Emphasis on the experiments and theoretical modelling were established for better accomplishments. Pulverised palm kernel and eggshell additives of 70 (wt.%) and 30 (wt.%) according to the Voige law of mixture was considered as a continuous medium without considering the atomic nature of the mixture. Furthermore, a kinetic approach was described where a physical model of the substrate immersed in the carbon mixture was established while diffusion equations were modelled to establish the mechanism of carbon diffusion during carburisation. Initial composition and concentration of diffused atom remained constant which are 2.68 and 6.67% carbon. While the carburizing time used varied from 60 min, 90 min, 120 min, 150 min, 180 min and 210 min respectively at constant carburising temperature of 900° The results revealed varying composition gradient of carbon atom ranging from 5.4%, 5.42%, 5.44%, 5.46%, 5.51%, and 5.65 compared to the initial carbon content of 2.68%. The concentration of carbon atom on the substrate surface at varying time implies that the process was non-steady state diffusion which verified Fick's second law of diffusion. Hence, the composition achieved is a function of boundary conditions such as time position and temperature. This novel study will enhance the understanding of heat treat treatment of metals such that their applications in the industry will be numerous.

A comparative analysis of the chemical composition and compliance level to established standards of concrete reinforcement steel rods rolled in Nigeria.

Nigeria is presently facing the challenges of collapsing buildings and bridges due to substandard materials used as reinforcement products. The increasing use of scraps as feedstock for the production of reinforcing steel bars by steel rolling mill companies has adversely affected the quality of rebars in Nigeria. This research study aimed to appraise the chemical properties of selected brands of steel rebars of Nigeria. Thirty selected brands of rebars were sourced from the six geopolitical zones in Nigeria, and their chemical compositions were analysed for level of compliance with five selected standards (SON, BSI, ASTM, AISI, ISO). The chemical composition test was performed using Optical Light Spectrometric methods. One way analysis of variance (ANOVA) test was performed using SPSS version 20 to examine whether significant differences exist or not in mean chemical composition for the different categories of selected steel rods. Statistical analysis shows a significant difference (P < 0.05) in chemical composition and compliance level between the different types of selected steel rods. The imported steel rods recorded the highest mean (µ = 101.4) in terms of chemical composition and compliance, followed by locally rolled from imported billets (µ = 101.2), TMT steel rods (µ = 101.0), and ordinary steel rods (µ = 100.6). Concerning CEV1 and CEV2, it was observed that all the brands were fully compliant within the maximum permissible ranges given in the local, foreign and international standards except an ordinary steel bar of Brand 16, which has value beyond the specified limits of CEV1. This study also shows that all imported and 77.8% of locally-rolled steel bars are low-carbon steel as specified by the selected standards.

Comprehensive data on the mechanical properties and biodegradation profile of polylactide composites developed for hard tissue repairs.

Polylactide (PLA), a biopolymer, was reinforced with three fillers (two organic reinforcements and one inorganic filler). The processing technique used to fabricate the composites was the melt-blending technique. The composites and the unreinforced PLA were subjected to microhardness, compression and biodegradation characterisations. Data obtained are presented in this article as raw data. Data from microhardness and compression tests were used to predict the fracture toughness. The biodegradation of the composites was also examined, and the data obtained reported in this article. The data presented in this article allow for a comprehensive understanding of the mechanical behaviour and the biodegradation profile of three composites of PLA with respect to their applications as biodegradable implants. It also helps in the selection of fillers for biopolymers such as PLA.

Investigation of the effects of selected bio-based carburising agents on mechanical and microstructural characteristics of gray cast iron.

The mechanism of graphite formation on gray cast iron metal during carburisation process using organic nano-carbon (ONC) was investigated at 900 °C for a holding time of three (3) hours. TEM and XRD were employed to characterize the pulverised nano-carbon to determine their phases and bonding potentials. Also, SEM/EDS, XRD and Vickers' hardness tester were employed to determine the microstructure, phase compositions as well as hardness and wear properties of the carburised material. The microstructural result showed that, there was uniform carbon diffusion into the substrate material which led to layers of graphite formation and subsequent surface modifications for each of the selected nano-carbon used. Also, the XRD results revealed variations in the peak patterns for each of the substrate carburised with different organic carbon with substrates showing graphite and iron phases as observed in that carburised in pulverised palm kernel shell having broad peaks at 35.50o, 44.4o, 65.12o and 82.395o. This is traceable to amorphous properties and crystalline behaviour of the organic carbon. Further to this, the micro-hardness measurement showed that substrate carburised using pulverised palm kernel shell performed better compared to other substrates in other media with a micro hardness value of 355.8 (HV) against as-received which is 116.9 (HV). Thus, this is a novel and possible method of improving the properties of grey cast iron to meet the increasing demand in gear applications.

Data on drying kinetics of a semi-automated gas-fired fish dryer.

The dataset presented in this article represent the drying characteristics of a semi-automated gas-fired fish dryer. A cabinet dryer was constructed mainly from mild steel sheet metal and stainless steel, and was used for drying prepared fish samples of Clarias gariepinus species. Major operating parameters which included mass of fish, mass of Liquefied Petroleum Gas used, inside temperature of the dryer, and drying time were monitored. Also, output parameters such as the moisture content and energy utilization amongst others were observed and recorded at varying time intervals and specified drying temperatures. The drying temperature was sustained via an incorporated PID temperature controller that allowed drying to proceed until a relatively constant mass of the dried fish samples was attained. The information contained in this data article include a schematic drawing of drying kinetics analysis of the semi-automated gas-fired fish dryer and a pictorial view of the gas-fired cabinet dryer. Also included are pictorial representations of the washed and neatly folded degutted fish samples and dried fish samples. Data provided in this article are those relating to process parameters of the semi-automated fish dryer, data of output parameters of the fish dryer and comparisons of moisture content and energy utilization at different drying temperatures with time.

Data on the no-load performance analysis of a tomato postharvest storage system.

In this present investigation, an original and detailed empirical data on the transfer of heat in a tomato postharvest storage system was presented. No-load tests were performed for a period of 96 h. The heat distribution at different locations, namely the top, middle and bottom of the system was acquired, at a time interval of 30 min for the test period. The humidity inside the system was taken into consideration. Thus, No-load tests with or without introduction of humidity were carried out and data showing the effect of a rise in humidity level, on temperature distribution were acquired. The temperatures at the external mechanical cooling components were acquired and could be used for showing the performance analysis of the storage system.

Degradation of polynuclear aromatic hydrocarbons by two strains of Pseudomonas

ABSTRACT The goal of this investigation was to isolate competent polynuclear aromatic hydrocarbons degraders that can utilize polynuclear aromatic hydrocarbons of former industrial sites at McDoel Switchyard in Bloomington, Indiana. Using conventional enrichment method based on soil slurry, we isolated, screened and purified two bacterial species strains PB1 and PB2. Applying the ribotyping technique using the 16S rRNA gene analysis, the strains were assigned to the genus Pseudomonas (Pseudomonas plecoglossicida strain PB1 and Pseudomonas sp. PB2). Both isolates showed promising metabolic capacity on pyrene sprayed MS agar plates during the preliminary investigations. Using time course studies in the liquid cultures at calculated concentrations 123, 64, 97 and 94 ppm for naphthalene, chrysene, fluroanthene and pyrene, P. plecoglossicida strain PB1 and Pseudomonas sp. PB2 showed partial utilization of the polynuclear aromatic hydrocarbons. Naphthalene was degraded between 26% and 40%, chrysene 14% and 16%, fluroanthene 5% and 7%; pyrene 8% and 13% by P. plecoglossicida strain PB1 and Pseudomonas sp. PB2 respectively. Based on their growth profile, we developed a model R2 = 1 to predict the degradation rate of slow polynuclear aromatic hydrocarbon-degraders where all the necessary parameters are constant. From this investigation, we confirm that the former industrial site soil microbial communities may be explored for the biorestoration of the industrial site.

Degradation of polynuclear aromatic hydrocarbons by two strains of Pseudomonas.

The goal of this investigation was to isolate competent polynuclear aromatic hydrocarbons degraders that can utilize polynuclear aromatic hydrocarbons of former industrial sites at McDoel Switchyard in Bloomington, Indiana. Using conventional enrichment method based on soil slurry, we isolated, screened and purified two bacterial species strains PB1 and PB2. Applying the ribotyping technique using the 16S rRNA gene analysis, the strains were assigned to the genus Pseudomonas (Pseudomonas plecoglossicida strain PB1 and Pseudomonas sp. PB2). Both isolates showed promising metabolic capacity on pyrene sprayed MS agar plates during the preliminary investigations. Using time course studies in the liquid cultures at calculated concentrations 123, 64, 97 and 94ppm for naphthalene, chrysene, fluroanthene and pyrene, P. plecoglossicida strain PB1 and Pseudomonas sp. PB2 showed partial utilization of the polynuclear aromatic hydrocarbons. Naphthalene was degraded between 26% and 40%, chrysene 14% and 16%, fluroanthene 5% and 7%; pyrene 8% and 13% by P. plecoglossicida strain PB1 and Pseudomonas sp. PB2 respectively. Based on their growth profile, we developed a model R(2)=1 to predict the degradation rate of slow polynuclear aromatic hydrocarbon-degraders where all the necessary parameters are constant. From this investigation, we confirm that the former industrial site soil microbial communities may be explored for the biorestoration of the industrial site.