NOVI MODEL ZA PREDVIĐANJE NAPREDOVANJA TUNELSKOGA BUŠAĆEG STROJA U TVRDIM STIJENAMA

The prediction of the advance rate of a Tunnel Boring Machine (TBM) in hard rock conditions is one of the most important concerns for estimating the time and costs of a tunnel project. In this paper, in the first step, a model based on Rock Engineering Systems (RES) is proposed to predict geotechnical risks (representing media characteristics) in rock TBM tunnelling. Fifteen main parameters that influence the geotechnical hazards were used in the modelling. In establishing an interaction matrix and also a parameter rating, the views of five experts were taken into account. The Vulnerability Index (VI) (geotechnical risk levels) for 2058 datasets out of 2168 sets of data from 53 geological zones in 11 km of the Zagros long tunnel was obtained. In the second step, based on the machine operating parameters such as torque, cutter head rotation per minute, cutter normal force and media characteristics (represented by VIs), which were used as input parameters and advance rate was used as an output parameter, while using 2058 datasets, linear and non-linear multiple regression analyses were carried out. 110 datasets (out of 2168 datasets), which were not used in the modelling, were applied to evaluate the performance of regression models and other models in literature and the results were compared. The obtained results showed that the new linear model proposed with R2=0.83 and RMSE=0.12 has a better performance than the other models.Predviđanje brzine napredovanja tunelskoga bušaćeg stroja u tvrdim stijenama jedna je od najvažnijih stvari kod procjene vremena i troškova izradbe tunela. Prikazana je priprema stijenskoga inženjerskog sustava, modela kojim se predviđa geotehnički rizik (ovisan o svojstvima stijena) kod izradbe tunela bušaćim strojevima. Uporabljeno je 15 varijabli koje utječu na spomenuti rizik. Na temelju 5 ekspertnih mišljenja postavljena je interakcijska matrica i rangiranje varijabli. Indeks ranjivosti, kao izvedenica geotehničkoga rizika, izračunan je za 2058 (od ukupno 2168) skupova podataka, uzorkovanih u 55 geoloških zona kroz 11 km dugačak tunel Zagros. U sljedećemu koraku proučeni su operativni parametri strojeva poput okretnoga momenta, rotacije glave sjekača po minuti, sile na glavi te svojstava stijena (prikazanih indeksom ranjivosti). Oni su bili ulazne varijable, a iznos napredovanja izlazna. Na temelju 2058 podataka izračunane su linearne i nelinearne višestruke regresije. Dodatnih 110 podataka (nisu korišteni za modeliranje) uporabljeni su za provjeru regresijskih (i drugih) modela. Rezultati su pokazali kako novi linearni model, s vrijednostima R2 = 0,83 i RMSE = 0,12, ima bolja svojstva nego drugi razmatrani modeli

MODELIRANJE NEIZRAVNOM LOGIKOM U PREDVIĐANJU STUPNJA GEOTEHNIČKIH RIZIKA KOD BUŠENJA STIJENA METODOM STROJNOGA BUŠENJA TUNELA

This study aims to analyze the level of geotechnical risks and predict the advance rate in rock Tunnel Boring Machine (TBM) tunnelling, using a multi-stage fuzzy logic modelling. Twelve parameters, affecting the geotechnical hazard scenario occurrence, which were clustered into five groups, were used as input parameters and the risk level was used as an output parameter. Also, based on the relation between the risk levels and advance rates, a predictive model for advance rate prediction was proposed. To validate the performance of modelling carried out, data from 58 geological zones in section two of the Zagros tunnel, Iran were used. The obtained results showed that by using the fuzzy logic-based model, in most zones, the risk levels estimated are in good agreement with field observations. Moreover, as expected, the high coefficient of determination (R2) of 0.91 between the risk level estimated and the average advance rate achieved in 58 analyzed zones, confirms the ability of the model proposed to predict the level of geotechnical risks. Furthermore, R2= 0.93, Root Mean Square Error (RMSE) of 0.62 and Variance Accounted For (VAF) of 97.51 between the measured and predicted advance rates show the good performance of the new predictive model developed for the advance rate estimation.U radu je analiziran stupanj geotehničkoga rizika i iznosa napredovanja kod bušenja tunela u stijenama metodom strojnoga bušenja tunela. Pri tomu je uporabljeno višestupanjsko modeliranje neizravnom logikom. Promatrano je 12 varijabli koje utječu na pojavu geotehničkoga rizika. One su svrstane u 5 skupina obilježenih vrijednostima rizika. Predviđen je model napredovanja bušenjem, na temelju rizika i brzine bušenja. Model je provjeren podatcima iz 58 geoloških zona koje su opažene tijekom bušenja sekcije broj 2 u tunelu Zagros (Iran). Rezultati pokazuju kako je primjena neizravne logike u većini zona dovela do procjene rizika koja je u skladu s terenskim opažanjima. Nadalje, velik iznos koeficijenta determinacije (0,91) između procijenjenoga rizika i prosječnoga stupnja napredovanja u 58 zona potvrdio je primjenjivost modela za predviđanje geotehničkoga rizika. Osim toga, vrijednosti R2 = 0,93, srednje kvadratne pogrješke 0,62 i varijance 97,51 između izmjerenoga i predviđenoga iznosa napredovanja pokazale su se vrlo uporabljivim za izradbu novoga modela predviđanja stupnja napredovanja

A perspective analysis about the effects of dams - Evidence from Iran

The construction of dams is one of the main mechanisms undertaken by policy makers for managing the challenge of water scarcity in recent decades, but this strategy can lead to negative social, economic and environmental consequences. The purpose of this study was to investigate a perspective analysis about the effects of construction of the dam on the Sirvan River in Iran. A sample of 273 rural households was selected using Cochran’s formula by use of multi stage sampling technique. In the mentioned villages, 36 key-informants were selected and interviewed. The results showed that the residents of rural areas were dissatisfied with the construction of the dam. Daryan dam construction in the region, in the social dimension, reduced the components of social capital by nearly 20%; in the economic dimension, reduced the economic components by nearly 24%; but in the infrastructure dimension, has improved the infrastructure of rural areas by only 4%. The results of t-test also show that the effect of dam construction in both economic and social dimensions was significant from the viewpoint of villagers and key-informants. The research results show significant negative effects of dam construction on social capital, trust and social participation. The viewpoint of villagers and key informants Daryan dam construction reduced the area under cultivation and production of the villagers of the region. However, in terms of infrastructure indicators, it has not been able to create positive and significant effects on the well-being of the villagers in the region

Prediction of damaged zone in longwall working panels

In longwall mining, the instability of roadways can affect the mine safety, production rate and consequently the economic condition of mine. Therefore their stability analysis is one the most important technical problems in underground mining. The stability analysis and the design of support systems have to be investigated from two points of view; 1) the pressure and displacements of damaged zone around gate roadways due to the construction process and stress redistribution and 2) the working loading due to coal seam extraction and overburden caving that extends the damaged zone size. The aim of this research is the calculation of working effect on the damaged zone around gate roadway considering geomechincal properties of medium and the geometric characteristic of the roads and working. Therefore, a method has been obtained to calculate the total damaged zone area and working influence coefficient using geometric concepts and mathematical relations, then a design algorithm has been suggested based on the obtained method

Evaluation of the influences of various force magnitudes and configurations on scoliotic curve correction using finite element analysis

Scoliosis is a lateral curvature in the normally straight vertical line of the spine, and the curvature can be moderate to severe. Different treatment can be used based on severity and age of subjects, but most common treatment for this disease is using orthosis. To design orthosis types of force arrangement can be varied, from transverse loads to vertical loads or combination of them. But it is not well introduced how orthoses control scoliotic curve and how to achieve the maximum correction based on force configurations and magnitude. Therefore, it was aimed to determine the effect of various loads configurations and magnitudes on curve correction of a degenerative scoliotic subject. A scoliotic subject participated in this study. The CT-Scan of the subject was used to produce 3D model of spine. The 3D model of spine was produced by Mimics software and the finite element analysis and deformation of scoliotic curve of the spine under seven different forces and in three different conditions was determined by ABAQUS software. The Cobb angle in scoliosis curve decreased significantly by applying forces. In each condition depends on different forces, different corrections have been achieved. It can be concluded that the configurations of the force application mentioned in this study is effective to decrease the scoliosis curve. Although it is a case study, it can be used for a vast number of subjects to predict the correction of scoliosis curve before orthotic treatment. Moreover, it is recommended that this method and the outputs can be compared with clinical findings

Evaluation of the magnitude of hip joint deformation in subjects with avascular necrosis of the hip joint during walking with and without Scottish Rite orthosis

The femoral head in subjects with leg calve perthes disease (LCPD) is generally considerably deformed. It is debatable whether this deformation is due to an increase in applied loads, a decrease in bone mineral density or a change in containment of articular surfaces. The aim of this study was to determine the influence of these factors on deformation of the femoral head. Two subjects with LCPD participated in this study. Subject motion and the forces applied on the affected leg were recorded using a motion analysis system (QualsisTM) and a Kistler force plate. OpenSim software was used to determine joint contact force of the hip joint whilst walking with and without a Scottish rite orthosis. 3D Models of hip joints of both subjects were produced by Mimics software. The deformation of femoral bone was determined by Abaqus. Mean values of the force applied on the leg increased while walking with the orthosis. There was no difference between bone mineral density (BMD) of the femoral bone of normal and LCPD sides (p-value>0.05) and no difference between hip joint contact force of normal and LCPD sides. Hip joint containment appeared to decrease follow the use of the orthosis. It can be concluded that the deformation of femoral head in LCPD may not be due to change in BMD or applied load. Although the Scottish rite orthosis is used mostly to increase hip joint containment, it appears to reduce hip joint contact area. It is recommended that a similar study is conducted using a higher number of subjects

The effect of Nigella sativa extract on tracheal responsiveness and lung inflammation in ovalbumin-sensitized guinea pigs

OBJECTIVE: To examine the preventive effect of a hydro-ethanolic extract of Nigella sativa on the tracheal responsiveness and white blood cell count in the lung lavage fluid of sensitized guinea pigs. METHODS: Three groups of guinea pigs sensitized to intraperitoneally injected and inhaled ovalbumin were given drinking water alone (group S), drinking water containing a low concentration of N. sativa extract (group S+LNS) or drinking water containing a high concentration of N. sativa extract (group S+HNS). The tracheal responses of control animals (group C) and the three groups of sensitized guinea pigs (n = 7 for all groups) to methacholine were measured by the assessment of the tracheal smooth muscle response to increasing concentrations of methacholine, and the effective concentration causing 50% of the maximum response (EC50) was determined. Tracheal responses to 0.1% ovalbumin and white blood cell counts in the lung lavage fluid were also examined. RESULTS: The tracheal response of the group S guinea pigs to both methacholine and ovalbumin was significantly higher than the response of the controls (p<0.01 for both cases). The tracheal responses of the S+LNS and S+HNS groups to both methacholine and ovalbumin were significantly decreased compared to those of the S group (p<0.05 to p<0.01). The total white blood cell and eosinophil counts in the lung lavage fluid of group S were significantly higher than those of group C (p<0.01). The white blood cell counts in both treated groups showed significant improvements (p<0.01 for both cases). CONCLUSIONS: These results demonstrate the preventive effect of the N. sativa extract on the tracheal response and lung inflammation in sensitized guinea pigs

PROCJENA RIZIKA KOD ŠIROKOČELNOGA PRIDOBIVANJA UGLJENA USLIJED SLOMA RADNOG ČELA

Face failure is a typical phenomenon in longwall coal mines that can have a wide range of consequences. Face failure, which includes wall spall and roof collapse occurrences, is a hazardous virus that, if not managed, spreads fast across all stages of coal mining and has the potential to disable the mine. Based on this research, face failure may have a detrimental influence on technical, environmental, community, safety, and economic concerns, and its negative effects will leave an unfavourable legacy for the future. As a result, these impacts can be mitigated by effective management and risk management approaches. The quantitative and qualitative face failure risk model provided in this study has a considerable potential as a suitable tool for decision makers to analyse failure risk. Face failure-related high-risk variables can be discovered using this approach, which also makes comparing various mines easier from a face failure aspect. For validation, the model was evaluated in the Parvadeh, Negin and Pabedana coal mines. The study’s findings revealed that Parvadeh’s face failure risk factor was 5058, indicating a high risk in this mine due to mechanized mining. Furthermore, the scores of the Negin and Pabedana mines were computed as 3019 and 3165, respectively, indicating that they were in the moderate risk category owing to traditional mining.Slom čela tipična je pojava u širokočelnim rudnicima ugljena koja može imati širok raspon posljedica. Slom čela, što uključuje pojavu loma u bokovima prostorija i urušavanje krovine, opasna je pojava koja se, ako se ne kontrolira, brzo širi u svim fazama eksploatacije ugljena i ima potencijal da onesposobi rudnik. Ovo istraživanje pokazuje kako slom čela može imati štetan utjecaj na tehničke, ekološke, društvene, sigurnosne i ekonomske aspekte, a njegovi negativni učinci ostavit će nepovoljne posljedice za budućnost. Ovi se utjecaji mogu ublažiti učinkovitim pristupima upravljanja i upravljanja rizikom. Kvantitativni i kvalitativni model rizika od kvara predočen u ovoj studiji ima znatan potencijal kao prikladan alat za donositelje odluka u analizi rizika štete. Pomoću ovoga pristupa mogu se otkriti varijable visokoga rizika povezane s kvarom na čeonim dijelovima, što također olakšava usporedbu rudnika s aspekta sloma na radnom čelu Za validaciju model je evaluiran u rudnicima ugljena Parvadeh, Negin i Pabedana. Nalazi studije otkrili su da je faktor rizika sloma čela Parvadeha bio 5058, što upućuje na visok rizik u ovome rudniku zbog mehaniziranoga rudarenja. Nadalje, rezultati rudnika Negin i Pabedana izračunani su kao 3019 odnosno 3165, što upućuje na to da su oni bili u kategoriji umjerenoga rizika zbog tradicionalnoga rudarenja

Evaluation of the Levetiracetam treatment on reduction of epileptic discharges in electroencephalogram in children with epilepsy.

Abstract: Objectives: Epilepsy is a relatively common disease in childhood. In some patients, despite clinical control of seizures, the electroencephalogram (EEG) is clearly abnormal. In some studies, the adverse effects of epileptic discharges on cognition, learning, behavior, and seizure recurrence in children have been identified. In this study, the effect of Levetiracetam on epileptic discharges in the interictal phase of EEG in children with epilepsy was investigated. Materials and Methods: In this clinical trial, 59 children aged 2 to 15 years with epilepsy, whose clinical seizures were controlled by sodium valproate in the last six months, but they still had epileptic discharges in the EEG, were randomly divided into two groups. Intervention group (24 people), whom Levetiracetam was added to sodium valproate, and control group, whom treatment with sodium valproate (35 people) alone was continued, then the patients were followed for one year. Results: The frequency of normalization of epileptic discharges in the intervention and control group was 66.7% and 57.1% (P = 0.500), respectively. The mean time for normalization of epileptic discharges in the interictal phase was 14.55%±14.31% &nbsp;&nbsp;months in the intervention group and 12.50%±20.18% &nbsp;&nbsp;months in the control group (P = 0.033). Conclusion: In children with controlled seizures whose EEG was still abnormal, both sodium valproate therapy alone and sodium valproate combined with Levetiracetam were effective in reducing the severity of epileptic discharges. But addition of Levetiracetam to sodium valproate normalizes EEG more rapidly.&nbsp;&nbsp