MULTIPLE DISCRETE-EVENT SIMULATION AND ANIMATION MODELS TO ASSIST MODERN MINING OPERATIONS

This research investigation was conducted to develop, execute, and analyze a collection of discrete-event system simulation and animation models for different modern mining operations and systems, including two open-pit gold mines, an aggregate mine (sand and gravel), an open-cast (strip) coal mine, and an underground mine evacuation operation. The mine simulation and animation models aimed to study and assess a wide range of practical unique and common "what if?" scenarios that the mine engineers and managers of the case studies posed in different aspects during the research. A comprehensive and detailed literature review was also performed to provide a summary of the published discrete-event system simulation projects and their applications in the mining and mineral industry. The simulation results of the investigation were effectively implemented to assist the engineers in maximizing the productivity of the mines, improving the operation processes, reducing the environmental impact of the haulage operations, and enhancing the equipment utilization in various case studies. In addition, due to the shortage of powerful and flexible computer simulation tools in designing and analyzing underground mining evacuation operations and rescue equipment with respect to the mine operating characteristics and layout, the discrete-event system simulation and animation technique was innovatively implemented for modeling these complex systems. GPSS/H® and PROOF Professional® were the simulation language and animation software used for this research work

The association of amniotic fluid cadmium levels with the risk of preeclampsia, prematurity and low birth weight

Background: Cadmium is an extremely toxic metal with ubiquitous environmental distribution. Cadmium is a potent reproductive and developmental toxic agent, and intensive environmental exposure to this substance has been reported among the residents of Tehran. In this study, we investigated the correlation between amniotic fluid cadmium levels and the risk of preeclampsia, prematurity and low birth weight. Methods: This study was conducted on 341 hospitalized pregnant women. Amniotic fluid samples were obtained during childbirth, prepared by acid digestion, and cadmium concentration was determined using atomic absorption spectrophotometer equipped with a graphite furnace. Results: In this study, the mean amniotic fluid cadmium concentration in non-smokers was significantly lower (780± 0.231 μg/l) compared to smokers (13.4±0.91 μg/l). Increased amniotic fluid cadmium levels were associated with the reduction of birth weight, and birth weight was below 2500 g in all the cases with amniotic fluid cadmium levels of >15μg/l. Moreover, preeclampsia was more prevalent among smoking mothers compared to non-smokers. The total incidence rate of preeclampsia (12.6) was significantly higher in this study compared to similar studies. In addition, no correlation was found between amniotic fluid cadmium levels and the rate of prematurity. Conclusion: According to the results of this study, cadmium levels of amniotic fluid could be used as sensitive and reliable biomarkers to monitor the reproductive and developmental toxicity of cadmium

Prevalence and risk factors for joint pain among men and women in the West of Scotland Twenty-07 study

Objective: To examine the association between three modifiable risk factors (obesity, smoking, and alcohol consumption) and reported joint pain. Methods: Cross sectional data were collected on 858 people aged 58 years living in the West of Scotland and on the same individuals four years later, aged 62 years. Results: There was a positive relation between obesity and reported pain in the hips, knees, ankles, and feet. The strongest relation was with knee pain (odds ratio = 2.42 (95% confidence interval, 1.65 to 3.56)). There were no strong consistent associations between smoking habits and pain in any joint after adjusting for sex, alcohol consumption, body mass index, social class, and occupational exposures. Similarly, alcohol was not consistently related to pain in any joint in the fully adjusted models. Conclusions: Obesity had consistent and readily explained associations with lower limb joint pain. The data suggest that smoking behaviour and alcohol consumption are not consistently associated with joint pain across the body

Short-term therapy with rosiglitatzone, a PPAR-¿ agonist improves metabolic profile and vascular function in non-obese lean wistar rats

A number of preclinical and clinical studies have reported blood-pressure-lowering benefits of thiazolidinediones in diabetic subjects and animal models of diabetes. This study was designed to further elucidate vascular effects of rosiglitazone, on healthy nonobese, lean animals. Adult male Wistar rats were randomized and assigned to control and rosiglitazone-treated groups and were dosed daily with either vehicle or rosiglitazone (10 mg kg(−1) day(−1)) by oral gavage for 5 days. Compared with control group, rosiglitazone treatment significantly reduced plasma levels of triglycerides (>240%) and nonesterified free fatty acids (>268%) (both, P < 0.001). There were no changes in vascular contractility to KCl or noradrenaline between two groups. However, rosiglitazone therapy improved carbamylcholine-induced vasorelaxation (93 ± 3 % versus control 78 ± 2, P < 0.01) an effect which was abolished by L-NAME. There was no difference in sodium nitroprusside-induced vasorelaxation between the control and rosiglitazone-treated animals. These results indicate that short-term rosiglitazone therapy improves both metabolic profile and vascular function in lean rats. The vascular effect of rosiglitazone appears to be mediated by alteration in NO production possibly by activation of endothelial PPARγ. This increased NO production together with improved lipid profile may explain mechanism(s) of blood-pressure-lowering effects of thiazolidinediones on both human and experimental animals

New Benzotriozole Phthalocyanine Nickel(II) Photostabilizer for Low Density Polyethylene

Benzotiozole Phthalocyanine Nickel(II) has been prepared and characterized by elemental analysis and FT-IR techniques. This new compound imposes three bathways to stablize low density polyethylene (LDPE) due to nature of its complex structure.The prepared complex contains four benzotrizoles which absorb U.V. light while Nickel(II) derivative destroye hydrogen peroxides and scavenge free radicals. The experimental investigation carried out on Benzotriozole phthalocyanine Nickel(II) shows that this complex has excellent photostabilizer for LDPE compared with commercial antioxidants. Keywords: Photostabilizer, Phthalocyanine Nickel(II) derivatives, LDP

Optimisation of quantum Monte Carlo wave function: steepest descent method

We have employed the steepest descent method to optimise the variational ground state quantum Monte Carlo wave function for He, Li, Be, B and C atoms. We have used both the direct energy minimisation and the variance minimisation approaches. Our calculations show that in spite of receiving insufficient attention, the steepest descent method can successfully minimise the wave function. All the derivatives of the trial wave function respect to spatial coordinates and variational parameters have been computed analytically. Our ground state energies are in a very good agreement with those obtained with diffusion quantum Monte Carlo method (DMC) and the exact results.Comment: 13 pages, 3 eps figure

Effect of diet-induced obesity on protein expression in insulin signalling pathways of skeletal muscle in male Wistar rats

BACKGROUND: The prevalence of diet-induced obesity is increasing globally, and posing significant health problems for millions of people worldwide. Diet-induced obesity is a major contributor to the global pandemic of type 2 diabetes mellitus. The reduced ability of muscle tissue to regulate glucose homeostasis plays a major role in the development and prognosis of type 2 diabetes. In this study, an animal model of diet-induced obesity was used to elucidate changes in skeletal muscle insulin signaling in obesity-induced diabetes. METHODS: Adult male Wistar rats were randomized and assigned to either a control group or to a test group. Controls were fed a standard laboratory pellet diet (chow-fed), while the test group had free access to a highly palatable diet (diet-fed). After 8 weeks, the diet-fed animals were subdivided into three subgroups and their diets were altered as follows: diet-to-chow, diet-fed with addition of fenofibrate given by oral gavage for a further 7 weeks, or diet-fed with vehicle given by oral gavage for a further 7 weeks, respectively. RESULTS: Untreated diet-fed animals had a significantly higher body weight and metabolic profile than the control chow-fed animals. Intramuscular triacylglyceride levels in the untreated obese animals were significantly higher than those in the control chow-fed group. Expression of protein kinase C beta, phosphatidylinositol 3, Shc, insulin receptor substrate 1, ERK1/2, and endothelial nitric oxide synthase was significantly increased by dietary obesity, while that of insulin receptor beta, insulin receptor substrate 1, and protein kinase B (Akt) were not affected by obesity. CONCLUSION: These data suggest that diet-induced obesity affects insulin signaling mechanisms, leading to insulin resistance in muscle

Critically phase-matched Ti:sapphire-laserpumped deep-infrared femtosecond optical parametric oscillator based on CdSiP2

We report a high-repetition-rate femtosecond optical parametric oscillator (OPO) for the deep-infrared (deep-IR) based on type-I critical phase-matching in CdSiP2 (CSP), pumped directly by a Ti:sapphire laser. Using angle-tuning in the CSP crystal, the OPO can be continuously tuned across 7306–8329 nm (1201–1369  cm−1) in the deep-IR. It delivers up to 18 mW of idler average power at 7306 nm and >7  mW beyond 8000 nm at 80.5 MHz repetition rate, with the spectra exhibiting bandwidths of >150  nm across the tuning range. Moreover, the signal is tunable across 1128–1150 nm in the near-infrared, providing up to 35 mW of average power in ∼266  fs pulses at 1150 nm. Both beams exhibit single-peak Gaussian distribution in TEM00 spatial profile. With an equivalent spectral brightness of ∼5.6×1020photons s−1 mm−2 sr−10.1% BW−1, this OPO represents a viable alternative to synchrotron and supercontinuum sources for deep-IR applications in spectroscopy, metrology, and medical diagnostics.Peer ReviewedPostprint (author's final draft

Hump on upper shelf of ductile-brittle transition temperature curve of a plain carbon steel

The ductile—brittle transition temperature (DBTT) in a plain carbon steel has been studied in a series of Charpy V notch samples. Both non-standard and standard samples were used in the as drawn, normalised and annealed conditions. In all cases, a hump was recorded on the upper shelf of the DBTT. Examination of fractures in the SEM in the vicinity of the hump showed typical microvoid coalescence. Low temperature fractures showed classical cleavage fractures with river markings. In the normalised and annealed conditions, both yield stress σy and impact transition temperature Tc varied inversely with square root of the ferrite grain size, in agreement with previous workers. However, the points for ‘as drawn’ samples lay off the linear plot. The reasons for this are discussed. The hump on the upper shelf of the DBTT is thought to be associated with dynamic strain aging