The influence of nanosecond fibre laser on the removal of paint on metallic surface

This research aims to study the effect of nanosecond laser parameters on the paint removal process and obtain a set of parameters that would result in the highest paint removal efficiency. In this study, the effect of laser paint removal parameters such as power, defocus distance, and the number of loops are studied with an optical microscope to observe surface features. The laser paint removal process is conducted using the IPG YLM 200/30 - Q pulsed fiber laser machine. The process sample was examined with an optical microscope to analyze the effectiveness of this laser paint removal process. The results indicated that the power and number of loops significantly enhance the paint removal process. The selection of correct frequency, power, hatching distance, scanning speed, and defocus distance also play a significant part in the efficiency of the laser paint removal process

Outbreak of Fatal Childhood Lead Poisoning Related to Artisanal Gold Mining in Northwestern Nigeria, 2010.

Background: In May 2010, a team of national and international organizations was assembled to investigate children's deaths due to lead poisoning in villages in northwestern Nigeria. Objectives: To determine the cause of the childhood lead poisoning outbreak, investigate risk factors for child mortality, and identify children aged <5 years in need of emergency chelation therapy for lead poisoning. Methods: We administered a cross-sectional, door-to-door questionnaire in two affected villages, collected blood from children aged 2-59 months, and soil samples from family compounds. Descriptive and bivariate analyses were performed with survey, blood-lead, and environmental data. Multivariate logistic regression techniques were used to determine risk factors for childhood mortality. Results: We surveyed 119 family compounds. One hundred eighteen of 463 (25%) children aged <5 years had died in the last year. We tested 59% (204/345) of children, aged <5 years, and all were lead poisoned (≥10 µg/dL); 97% (198/204) of children had blood-lead levels ≥45 µg/dL, the threshold for initiating chelation therapy. Gold ore was processed inside two-thirds of the family compounds surveyed. In multivariate modeling significant risk factors for death in the previous year from suspected lead poisoning included: the child's age, the mother performing ore-processing activities, community well as primary water source, and the soil-lead concentration in the compound. Conclusion: The high levels of environmental contamination, percentage of children aged <5 years with elevated blood-lead levels (97%, >45 µg/dL), and incidence of convulsions among children prior to death (82%) suggest that most of the recent childhood deaths in the two surveyed villages were caused by acute lead poisoning from gold ore-processing activities. Control measures included environmental remediation, chelation therapy, public health education, and control of mining activities

Susceptibility Status of The Malaria Vector Anopheles Arabiensis To Insecticides in Khartoum State, Sudan

Background: Increasing insecticide resistancein the major anopheline vectors remain the main obstacle for malaria control programmes in African countries including Sudan.Objectives: To assess the susceptibility status of Anopheles arabiensis the malaria vector to different classes of insecticides in Khartoum State.Materials and Methods: Using WHO procedure, susceptibility tests were conducted on adults of An.arabiensis from nine sentinel sites in Khartoum State. Mortality rates and knockdown times of insecticides for An. arabiensis were calculated.Results: A total of 8345 females of An.arabiensis were tested againsteight insecticides, these wereDDT 4%, fenitrothion 1%, malathion 5%, propoxur 0.1%, permethrin 0.75%, deltamethrin 0.05% and lambdacyhalothrin 0.05%. Of these insecticides tested, An. arabiensis from Khartoum State wassusceptible to only fenitrothion 1% and lambdacyhalothrin 0.05% with overall mean percentage mortalities 99±0.12 and 100±0.45 respectively.In addition, the overall results, revealed a low mean mortality rates in An. arabiensis indicating resistance to the other remaining insecticides.Furthermore, all populations of An. arabiensis from different sentinel sites showed variation in mortality rates for the tested insecticides. The exception were for fenitrothion 1% and lambdacyhalothrin 0.05% which were resulted in 100% mean mortality in An. Arabiensis in each sentinel sites. Similarly, the knock down time (KDT) of all insecticide tested for 50% and 95% of An. arabiensis varied between populations of sentinel sites.Conclusion: In conclusion, An. arabiensis the main malariavector in Khartoum State is mainly susceptible to fenitrothion and lambdacyhalothrin. Therefore, these two insecticides could be the more suitable for malaria vector control in Khartoum State.Key Words: Anopheles arabiensis; susceptibility; KDT, Khartoum State, Suda

Effect of cobalt nanoparticles on mechanical properties of Sn–58Bi solder joint

Brittle phases are responsible for crack formation and propagation in tin–bismuth (Sn–58Bi) solder material. The purpose of this work is to investigate the effects of various cobalt (Co) nanoparticle (NP) concentrations on the tensile properties of the Sn–58Bi solder matrix. Different aging times were studied to find out the effect of Co NP on ultimate tensile strength. Tin–bismuth solder joints of different Co NP concentrations of 0%, 0.5%, 1%, and 2% were prepared. The reflow process was done at 180 °C for 1 min. Scanning Electron Microscopy and Energy-Dispersive X-ray spectroscopy were used to analyze the solder joints. The tensile test was carried out for the Sn–58Bi and Sn–58Bi–xCo (x = 0.5, 1, and 2) solder joints. The tensile test was run before and after aging time. The tensile results reveal that the addition of Co NP increased the tensile strength significantly at different concentrations of Co NP. The Tensile test revealed that ductility was improved as the temperature was increased. As the aging time increased, the ultimate tensile strength of all samples decreased

Multi-objective optimization of process parameters during micro-milling of nickel-based alloy Inconel 718 using Taguchi-grey relation integrated approach

This research investigates the machinability of Inconel 718 under conventional machining speeds using three different tool coatings in comparison with uncoated tool during milling operation. Cutting speed, feed rate and depth of cut were selected as variable machining parameters to analyze output responses including surface roughness, burr formation and tool wear. It was found that uncoated and AlTiN coated tools resulted in lower tool wear than nACo and TiSiN coated tools. On the other hand, TiSiN coated tools resulted in highest surface roughness and burr formation. Among the three machining parameters, feed was identified as the most influential parameter affecting burr formation. Grey relational analysis identified the most optimal experimental run with a speed of 14 m/min, feed of 1 mu m/tooth, and depth of cut of 70 mu m using an AlTiN coated tool. ANOVA of the regression model identified the tool coating parameter as most effective, with a contribution ratio of 41.64%, whereas cutting speed and depth of cut were found to have contribution ratios of 18.82% and 8.10%, respectively. Experimental run at response surface optimized conditions resulted in reduced surface roughness and tool wear by 18% and 20%, respectively.Web of Science1523art. no. 829

A Fully Automated and Explainable Algorithm for the Prediction of Malignant Transformation in Oral Epithelial Dysplasia

Oral epithelial dysplasia (OED) is a premalignant histopathological diagnosis given to lesions of the oral cavity. Its grading suffers from significant inter-/intra- observer variability, and does not reliably predict malignancy progression, potentially leading to suboptimal treatment decisions. To address this, we developed a novel artificial intelligence algorithm that can assign an Oral Malignant Transformation (OMT) risk score, based on histological patterns in the in Haematoxylin and Eosin stained whole slide images, to quantify the risk of OED progression. The algorithm is based on the detection and segmentation of nuclei within (and around) the epithelium using an in-house segmentation model. We then employed a shallow neural network fed with interpretable morphological/spatial features, emulating histological markers. We conducted internal cross-validation on our development cohort (Sheffield; n = 193 cases) followed by independent validation on two external cohorts (Birmingham and Belfast; n = 92 cases). The proposed OMTscore yields an AUROC = 0.74 in predicting whether an OED progresses to malignancy or not. Survival analyses showed the prognostic value of our OMTscore for predicting malignancy transformation, when compared to the manually-assigned WHO and binary grades. Analysis of the correctly predicted cases elucidated the presence of peri-epithelial and epithelium-infiltrating lymphocytes in the most predictive patches of cases that transformed (p < 0.0001). This is the first study to propose a completely automated algorithm for predicting OED transformation based on interpretable nuclear features, whilst being validated on external datasets. The algorithm shows better-than-human-level performance for prediction of OED malignant transformation and offers a promising solution to the challenges of grading OED in routine clinical practice