UTJECAJ GEOLOŠKIH SVOJSTAVA ARHITEKTONSKO-GRAĐEVNOGA KAMENA NA PREDVIĐANJE SPECIFIČNE ENERGIJE TIJEKOM REZANJA DIJAMANTNOM ŽICOM

Given the increasing demand for dimension stones, mining operations in quarries have always been an important branch of mining engineering. Among different techniques, diamond wire cutting is one of the most common methods of dimension stone mining. A reliable assessment and accurate prediction of diamond wire cutting performance are essential for feasibility analysis and operational planning in this area. This performance depends on factors such as physical, mechanical, and textural properties of the rock and the characteristics of cutting operations which can be evaluated by criteria such as specific energy, production rate, efficiency, and diamond bead wear rate. This study aims to develop a method for predicting the specific energy of diamond wire cutting in dimension stones based on rock properties. For this purpose, the specific energy of diamond wire cutting in 11 different igneous rock samples was measured. Given the high strength and abrasivity of igneous rocks, cutting operations in these rocks generally requires a great amount of energy. In a series of tests performed on the samples, rock properties such as uniaxial compressive strength (UCS), Brazilian tensile strength (BTS), Young’s modulus, density, textural properties, abrasivity and operating factors such as pullback amperage were measured. The measured parameters were divided into four groups of physical, mechanical, textural, and operating parameters. After determining the specific cutting energy of each sample, the relationship of the energy with each individual property was investigated. This investigation showed that density, abrasivity, and p-wave velocity respectively had the highest correlation with specific energy. Using the correlation results, four input parameters (one from each of the four considered parameter groups) were selected for inclusion in the prediction model. These parameters were density, abrasivity, wave velocity, and amperage. Multivariate linear regression was then used to analyse the effect of rock properties and operating parameters on specific energy. The developed regression model showed that once the rock properties are known, the specific energy can be predicted with an accuracy of 85.8%. The proposed model can be used to estimate the specific energy of diamond wire cutting operations in dimension stone quarries in advance, and predict the amount of energy consumption, the required energy source, and the optimal cutting machine accordingly.Povećana potreba za arhitektonsko-građevnim kamenom stavlja naglasak na različite rudarske zahvate u kamenolomima. Od nekoliko tehnika rezanje dijamantnom žicom jedan je od najčešćih načina vađenja arhitektonsko-građevnoga kamena. Pouzdana i točna procjena svojstava takva rezanja nužna je za analizu isplativosti i osjetljivosti. Svojstva rezača ovise o nizu čimbenika poput fizičkih, mehaničkih i teksturnih svojstava stijena te samoga rezanja, a mogu biti procijenjena iz varijabli poput specifične energije, iznosa proizvodnje, efikasnosti i habanja. U studiji je razvijena metoda za predviđanje specifične energije rezanja dijamantnom žicom uzoraka 11 različitih magmatskih stijena. Zbog njihove velike čvrstoće i abrazivnosti rezanje takvih uzoraka zahtijeva znatnu energiju. Testirano je niz svojstava kao što su jednoosna tlačna čvrstoća, vlačna čvrstoća određena brazilskim testom, Youngov modul, svojstva tekstura, abrazivnost i faktori poput potrebne struje. Nakon određivanja specifične energije rezanja svakoga uzorka analiziran je odnos energije i svakoga nabrojanog svojstva. Rezultati su pokazali kako su gustoća, abrazivnost te brzina p-valova u najvećoj korelaciji sa specifičnom energijom. Odabrane su, temeljem korelacije, četiri ulazne varijable koje su uključene u model predviđanja (gustoća, abrazivnost, brzina širenja valova, jakost struje). Utjecaji svojstava stijena i radnih parametara na specifičnu energiju analizirani su višestrukom linearnom regresijom. Regresijski model pokazao je kako se na temelju svojstava stijena iznos specifične energije može predvidjeti točnošću od 85,8 %. Takav model može se koristiti kod predviđanja specifične energije potrebne za rezanje arhitektonsko-građevnoga kamena u kamenolomima, tj. predviđanje utroška i izvora energije te optimiziranje rezaćega stroja

ISTRAŽIVANJE SVEOBUHVATNOGA MODELA ZA PROCJENU OBRADBENOGA I OKOLIŠNOGA RIZIKA KOD VAĐENJA ARHITEKTONSKO-GRAĐEVNOGA KAMENA

One of the most hazardous fields of engineering is mining operations and accordingly, it requires extra consideration on risk evaluation. Decorative stone quarrying is one of the main branches of the mining industry in Iran. Currently, Iran, China and Italy are known as the three main producers of decorative stones in the world. Subsequently, risk assessment is one of the main steps of quarrying organization. One of the main steps of risk assessment is Risk Breakdown Structure (RBS). In order to achieve this goal, a comprehensive structure of dimensional stone quarrying is modelled in this research and divided into 17 main levels. One of the most useful procedures of risk ranking is Multi attribute decision-making methods which state that they have numerous affecting parameters. In the next step of this study, the main hazards of main decorative stone quarrying are assessed by implementing the ‘Preference Ranking Organization Method for Enrichment Evaluation’ (PROMETHEE) technique. As a final point, Economical, Management, and Schedule risks are determined as the most intimidating hazards in this field.Jedna od najopasnijih inženjerskih aktivnosti jesu rudarske operacije koje stoga zahtijevaju dodatne procjene rizika. Vađenje ukrasnoga kamena jedna je od glavnih rudarskih grana u Iranu. Trenutačno su Iran, Kina i Italija tri glavna proizvođača takva kamena u svijetu. Procjena rizika među temeljnim je aktivnostima kamenoloma. Jedan od glavnih postupaka toga procesa jest procjena rizika loma strukture (RLS). S tim ciljem modelirane su makrostrukure arhitektonsko-građevnoga kamena te su podijeljene u 17 razina. Jedan od najboljih postupaka za rangiranje rizika jest višeatributna metoda donošenja odluka koja povezuje brojne zavisne parametre. Nadalje, ocijenjeni su glavni rizici u najvećim kamenolomima uporabom metode preferirajućega rangiranja za poboljšanu procjenu (MPRPP). Na kraju su izračunani ekonomski rizik te rizici upravljanja i planiranja, koji ujedno imaju najveći utjecaj na opisane aktivnosti

The Effect of 8 Weeks of Resistance Training and Supplementation of Apple Vinegar on Resistin and Glycemic Indices in Obese Women

Introduction: The use of antioxidant and anti-inflammatory supplements is important in improving the function of obese people. The aim of this study was to investigate the effect of 8 weeks of resistance training with apple vinegar on resistin and glycemic indices of obese women.Method: 60 women (mean ± SD: age 23.8 ± 4.81 years, weight 89.04 ± 4.68 and body mass index 34.39 ± 4.31 kg / m2) were purposefully selected and randomly assigned to four groups of 15: 1-resistance training, 2- resistance training and apple vinegar, 3-apple vinegar and 4-control Groups 1 and 2 performed 8 weeks of resistance training, 3 sessions per week and 60 minutes each session with 80% intensity of 1RM. During this period, groups 2 and 3 consumed 500 mg of apple vinegar per day and the control group did not receive any interventions. Blood samples were taken before and after the study period. To analyze the findings, paired sample t-test, one-way ANOVA and Bonferroni post hoc test were used (p≤0.05). Result: Resistance training, apple vinegar consumption, and resistance training with apple vinegar had a significant effect on decreasing resistin, insulin, fasting glucose and insulin resistance in obese women (p≤0.05). Resistance training with apple vinegar compared with resistance training and apple vinegar consumption had a greater effect on decreasing resistin, insulin, fasting glucose and insulin resistance in obese women (p≤0.05). Conclusion: It seems that apple vinegar supplementation and resistance training are likely to be a suitable method for reducing resistine and glycemic indexes and preventing metabolic, cardiovascular and inflammatory diseases in obese women

ISTRAŽIVANJE ZVUČNOGA ZAPISA U RAZLIČITIM VRSTAMA STIJENA NA TEMELJU VRIJEDNOSTI RMS ZVUČNOGA SIGNALA

Recent years have seen a vast increase in the use of acoustic waves in real-time and non-destructive detection and monitoring applications in various industries such as mining. Acoustic signal processing methods can provide accurate and reliable estimates of the condition of a process or material in a highly cost-effective way without interrupting the ongoing operations. This paper investigated whether the class of a rock and its strength properties can be estimated based solely on acoustic signals captured during drilling operations. For this purpose, uniaxial compressive strength (UCS), Brazilian tensile strength (BTS), the Schmidt rebound number (SRN), and longitudinal wave velocity (Pw) of a series of samples of sedimentary, metamorphic and igneous rocks were measured in a rock mechanics laboratory. The samples were then subjected to a drilling test and the acoustic signal propagating in the drilling medium was recorded by an acoustic sensor. After obtaining the time spectrum of the captured signals, their RMS values were calculated and compared with the mechanical properties of the corresponding rock samples. For the rocks tested in this study, the obtained RMS values were in the range of 800 to 1,600, and generally increased with an increase in strength and hardness. The RMS values obtained for each class of rocks had their own specific range. For sedimentary rocks, this range was 800 to 1000, for metamorphic rocks, it was 1000 to 1200, and for igneous rocks, it was 1400 to 1600. Given the differences in the range of RMS values obtained from the acoustic signals of drilling, these values can be used in the estimation of rock class and strength properties. These results show that there is significant potential for the future use of this approach in the industry for field identification and classification of rocks, especially in deep drilling operations or when there is little information about the characteristics of the rock being drilled.Proteklih godina ostvaren je velik napredak u uporabi zvučnih valova kao trenutačne i neinvazivne metode opažanja i praćenja različitih operacija u rudarstvu i drugim industrijskim granama. Obradba zvučnih signala može omogućiti točnu i pouzdanu procjenu uvjeta procesa ili materijala na ekonomski vrlo isplativ način te bez prekidanja tekućih radova. Ovdje je prikazano ispitivanje sa svrhom mogućnosti procjene vrste i čvrstoće stijene isključivo uporabom zvučnih valova, a tijekom bušenja. Izmjereno je na nizu uzoraka taložnih, metamorfnih i magmatskih stijena vrijednosti jednoosne tlačne čvrstoće, brazilskoga testa vlačne čvrstoće, Schmidtova odskoka i brzine longitudinalnih valova. Zatim su uzorci podvrgnuti testu bušenja i širenja zvučnih valova u bušenome uzorku koji su i snimani. Dobivena je vremenska raspodjela takvih signala, a izračunane su njihove RMS vrijednosti i uspoređene su s mehaničkim svojstvima odgovarajućih stijenskih uzoraka. Kod stijena obrađenih ovim istraživanjem vrijednost RMS-a kretala se između 800 i 1600, a općenito je rasla s povećanjem čvrstoće i tvrdoće. Vrijednosti RMS-a prikupljene su za svaku klasu stijena u specifičnome intervalu. Kod taložnih on je iznosio 800 – 1000, metamorfnih 1000 – 1200 i magmatskih 1400 – 1600. Razlike u vrijednostima RMS-a dobivene iz zvučnih signala generiranih bušenjem mogu se koristiti za procjenu vrste i čvrstoće stijena. Rezultati pokazuju kako takav pristup ima znatan potencijal za buduću uporabu kod terenskoga prepoznavanja i razvrstavanja stijena, posebno kod dubokih bušenja, a pogotovo u slučajevima kada je takvim bušenjima prikupljeno malo podataka

APPLICATION OF ACOUSTIC EMISSION (AE) IN MINING AND EARTH SCIENCES: A REVIEW

Jedan od najčešće primjenjivanih alata u rudarstvu i znanostima o Zemlji jesu visokofrekvencijski, elastični, zvučni valovi. Oni mogu biti koristan alat za predviđanje i mjerenje, praćenje i prepoznavanje okoliša te su specifični, mjerljivi, dostupni, pouzdani i utemeljeni na vremenu (skr. SMDPV, engl. SMART). Emitiranje zvuka može biti dijelom inženjerskih operacija poput otkapanja, procjene volumena ili istraživanja. Stoga su oni primijenjeni u opažanju, praćenju i mjerenju inženjerskih pojava. Razvojem obradbe zvučnih signala te rastućom potrebom za točnim, brzim i ekonomski povoljnim predviđanjem, praćenjem i mjerenjem, te metode postaju zamjena postojećim metodama druge vrste u različitim vrstama projekata. Ovdje su prikazane uporabe zvučnih valova u različitim znanostima o Zemlji, poput rudarstva, bušenja, geologije, naftnoga inženjerstva i sličnim granama. Primjena zvučnih valova podijeljena je u tri skupine: predviđanje i procjena, praćenje i procjena svojstava te opažanje. Njihovo korištenje u usporedbi s laboratorijskim i bušaćim tehnikama vrlo je brzo i točno, a uz odgovarajuću tehničku opremu signali se mogu primijeniti i obraditi na mjestima udaljenim od onih gdje se mjerenje izvodi. Na kraju je opisana primjena zvučnih metoda u procjeni različitih projekata kao alata za donošenja odluka.One of the most important products of the majority of tools, processes and, phenomena in mining engineering and earth sciences are high-frequency elastic waves, often referred to as acoustic waves. These acoustic waves can be a useful tool for prediction and measurement, monitoring and diagnosis. Due to the importance of engineering activities that should be specific, measurable, available, reliable and time-based (SMART), Acoustic Emission (AE) techniques can be integrated into engineering operations such as excavation to give exact estimations or simplify some aspects of investigations. Hence, these techniques are expected to play an increasing role in the detection, monitoring, and measurement in engineering applications. With the development of acoustic signal processing methods in earth sciences and the growing need for accurate, fast, and cost-effective prediction, monitoring and measurement methods, AE tools and techniques are expected to turn into powerful alternatives to current methods. The purpose of this paper is to review the application of the acoustic methods as a tool in various projects. For this purpose, the application of AE methods has been reviewed in different fields related to earth sciences including mining engineering, drilling engineering, geology, petroleum engineering, and other related fields. According to the purpose of using these methods, the application of AE is divided into three groups: prediction and estimation, monitoring and performance assessment, and detection. The use of AE methods, among other laboratory or in-situ methods, is very fast and accurate, and by only installing specific sensors with data logging equipment, it has been able to process and analyse data online and remotely. Finally, the possibility of using AE techniques in design and calculating in various projects and as a tool for decision making was evaluated

THE DEVELOPMENT OF A NOVEL MODEL FOR MINING METHOD SELECTION IN A FUZZY ENVIRONMENT; CASE STUDY: TAZAREH COAL MINE, SEMNAN PROVINCE, IRAN

Odabir rudarske metode za bilo koju mineralnu sirovinu najvažniji je korak kod započinjanja i održavanja uspješnoga rudarenja. S obzirom na velike troškove i utjecaj na okoliš odabranu rudarsku metodu pridobivanja obično je nemoguće promijeniti kada pridobivanje započne. Odabir metode uglavnom se temelji na geološkim i geometrijskim svojstvima sirovine, utjecaju na okoliš, mogućim opasnostima te općenito uporabi tla na kojemu se rudari. U radu je prikazan razvoj nove metode kojom se postiže stabilan iznos proizvodnje, ali i smanjuju problemi u okolišu. Njezina uporaba objašnjena je na primjeru rudnika ugljena Tazareh. Istaknuti su nedostatci prethodnih rudarskih metoda te kako su oni riješeni novim pristupom nazvanim TOPSIS. Rije« je o postupku odlučivanja s više varijabli, oblikovanome neizrazitom logikom. Danas je upravo ta metoda u primjeni u navedenome rudniku.Mining method selection (MMS) for mineral resources is one of the most significant steps in mining production management. Due to high costs involved and environmental problems, it is usually not possible to change the coal mining method after planning and starting the operation. In most cases, MMS can be considered as an irreversible process. Selecting a method for mining mainly depends on geological, geometrical properties of the resource, environmental impacts of exploration, impacts of hazardous activities and land use management. This paper seeks to develop a novel model for mining method selection in order to achieve a stable production rate and to reduce environmental problems. This novel model is illustrated by implementing for Tazareh coal mine. Given the disadvantages of the previous models for selecting coal mining method, the purpose of this research is modifying the previous models and offering a comprehensive model. In this respect, TOPSIS method is used as a powerful multi attribute decision-making procedure in Fuzzy environment. After implementation of the presented model in Tazareh coal mine, long wall mining method has been selected as the most appropriate mining method

Dynamics of GLP-1R peptide agonist engagement are correlated with kinetics of G protein activation

The glucagon-like peptide-1 receptor (GLP-1R) has broad physiological roles and is a validated target for treatment of metabolic disorders. Despite recent advances in GLP-1R structure elucidation, detailed mechanistic understanding of how different peptides generate profound differences in G protein-mediated signalling is still lacking. Here we combine cryo-electron microscopy, molecular dynamics simulations, receptor mutagenesis and pharmacological assays, to interrogate the mechanism and consequences of GLP-1R binding to four peptide agonists; glucagon-like peptide-1, oxyntomodulin, exendin-4 and exendin-P5. These data reveal that distinctions in peptide N-terminal interactions and dynamics with the GLP-1R transmembrane domain are reciprocally associated with differences in the allosteric coupling to G proteins. In particular, transient interactions with residues at the base of the binding cavity correlate with enhanced kinetics for G protein activation, providing a rationale for differences in G protein-mediated signalling efficacy from distinct agonists

The potential use of single-particle electron microscopy as a tool for structure-based inhibitor design

Recent developments in electron microscopy (EM) have led to a step change in our ability to solve the structures of previously intractable systems, especially membrane proteins and large protein complexes. This has provided new opportunities in the field of structure-based drug design, with a number of high-profile publications resolving the binding sites of small molecules and peptide inhibitors. There are a number of advantages of EM over the more traditional X-ray crystallographic approach, such as resolving different conformational states and permitting the dynamics of a system to be better resolved when not constrained by a crystal lattice. There are still significant challenges to be overcome using an EM approach, not least the speed of structure determination, difficulties with low-occupancy ligands and the modest resolution that is available. However, with the anticipated developments in the field of EM, the potential of EM to become a key tool for structure-based drug design, often complementing X-ray and NMR studies, seems promising