291 research outputs found

    Chemical-Rheological Evaluation of the Short-Term and Long-Term Effectiveness of Binder Rejuvenators

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    Many previous studies have investigated how rejuvenators affect/alter mechanical/chemical characteristics of aged binders. However, it has not been actively examined how the rejuvenated binders will perform for the next round of service after the rejuvenation was made. A better understanding of the short-term and long-term effect of rejuvenating agents in RAP blended asphalt mixtures is necessary to achieve more appropriate selection and use of rejuvenating agents

    An Experimental-Intelligent Method to Predict Noise Value of Drilling in Dimension Stone Industry

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    The noise of drilling in the dimension stone business is unbearable for both the workplace and the people who work there. In order to reduce the negative effects drilling has on the health of the environment, the drilling noise has to be measured, assessed, and controlled. The main purpose of this work is to investigate an experimental-intelligent method to predict the noise value of drilling in the dimension stone industry. For this purpose, 135 laboratory tests are designed on five types of rocks (four types of hard rock and one type of soft rock): and their results are measured in the first step. In the second step, due to the unpredicted and uncertain issues in this case, artificial intelligence (AI) approaches are applied, and the modeling is conducted using three intelligent systems (IS): namely an adaptive neuro-fuzzy inference system-SCM (ANFIS-SCM): an adaptive neuro-fuzzy inference system-FCM (ANFIS-FCM): and the radial basis function network (RBF) neural network. 75% of the samples are considered for training, and the rest for testing. Several models are constructed, and the results indicate that although there is no significant difference between the models according to the performance indices, the proposed construction of ANFIS-SCM can be considered as an efficient tool in the evaluation of drilling noise. Finally, several scenarios are designed with different input modes, and the results obtained prove that the types of rock and the drill bits are more important than the operational characteristics of the machine

    Effects of Rejuvenators on High-RAP Mixtures Based on Laboratory Tests of Asphalt Concrete Mixtures and Fine Aggregate Matrix Mixtures

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    Although the linear viscoelastic stiffness, fracture characteristics, and permanent deformation behavior of AC mixtures can be determined through experiments, it is generally time-consuming and expensive to reach statistically repeatable results. Thus, it is attractive to pursue alternative methods that are cheaper, faster, and repeatable in order to efficiently evaluate and predict asphalt mixtures’ core mechanical characteristics (such as stiffness, fatigue, and plastic deformation)

    A new conventional criterion for the performance evaluation of gang saw machines

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    Available online 20 June 2019The process of cutting dimension stones by gang saw machines plays a vital role in the productivity and efficiency of quarries and stone cutting factories. The maximum electrical current (MEC) is a key variable for assessing this process. This paper proposes two new models based on multiple linear regression (MLP) and a robust non-linear algorithm of gene expression programming (GEP) to predict MEC. To do so, the parameters of Mohs hardness (Mh), uniaxial compressive strength (UCS), Schimazek’s F-abrasiveness factor (SF-a), Young’s modulus (YM) and production rate (Pr) were measured as input parameters using laboratory tests. A statistical comparison was made between the developed models and a previous study. The GEP-based model was found to be a reliable and robust modelling approach for predicting MEC. Finally, according to the conducted parametric analysis, Mh was identified as the most influential parameter on MEC prediction.Sina Shaffiee Haghshenas, Roohollah Shirani Faradonbeh, Reza Mikaeil, Sami Shaffiee Haghshenas, Abbas Taheri, Amir Saghatforoush, Alireza Dormish

    Estimation of topographical effects at Narni ridge (Central Italy): comparisons between experimental results and numerical modelling

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    In the present work the seismic site response of Narni ridge (central Italy) is evaluated by comparing experimental results and numerical simulations. The inhabited village of Narni is located in the central Italian Apennines at the top of a steep massive limestone ridge. From March to September 2009 the site was instrumented with 10 weak-motion stations, 3 of which located at the base of the ridge and 7 at the top. The velocimetric network recorded 642 events of ML up to 5.3 and hypocentral distance up to about 100 km. The great amount of data are related to the April 2009 L’Aquila sequence. The site response was analyzed using both reference (SSR, Standard Spectral Ratio) and non reference spectral techniques (HVSR, Horizontal to Vertical Spectral Ratio). Moreover directional analyses were performed in order to evaluate the influence of the ridge orientation with respect to the selected source-site paths. In general the experimental results show amplification factors for frequencies between 4 and 5 Hz for almost all stations installed along the crest. The SSR technique provides amplification factors up to 4.5 detected considering directions perpendicular to the main elongation of the ridge. The results obtained from the monitoring activity were used as a target for bidimensional and tridimensional numerical simulations, performed using a hybrid finite-boundary element method for 2D and a boundary element method for 3D analyses respectively. In general, the results obtained through numerical simulation fit well the experimental data in terms of range of amplified frequencies, but they underestimate by a factor of about 2 the related amplification factors with respect to the observations

    An Audit of Nursing Care and Placement of Peripherally Inserted Central Catheter in Infants

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    Background and Objective: The performance quality of peripherally inserted central catheter (PICC) by nurses has a direct effect on the improvement of patient care and safety. The aim of this study is to audit the placement and nursing care of PICC in infants. Methods: This cross-sectional study was conducted on 130 PICC procedures in the neonatal intensive care units of Rouhani and Amirkola hospitals in Babol in 2018-2021. All infants who needed PICC placement for any reason were selected. In order to collect the data, the observational researcher-made checklist and the infant demographic characteristics questionnaire were used. The checklist included 44 questions and four parts of nursing care before catheter insertion, hand washing, nursing care during the procedure, and nursing care after catheter placement. The scores obtained from the checklist were classified into conversion percentage and two groups of unfavorable placement (less than 67) and favorable placement (68-100). To confirm its reliability, intraclass correlation coefficient was used (ICC=0.90). Findings: A total of 130 cases of PICC placement and nursing care were audited (Rouhani Hospital 98 cases 75.4%, Amirkola 32 cases 24.6%). In the studied sample, 83 (63.8%) were boys and 53 (43.1%) were diagnosed with prematurity. The most common PICC location was the armpit (42.3%). The percentages of compliance of nursing care before PICC insertion according to the standard (97.43%), hand washing (100%), nursing care during the procedure (87.14%) and nursing care after PICC insertion (94.84%) were favorable. Nurses did not use glasses and ultrasound guidance during PICC insertion; (85.4%) and (90%), respectively. Conclusion: According to the results of this study, although the quality of PICC insertion and care in three stages was at a favorable level, nurses need training regarding the use of glasses and ultrasound guidance during PICC insertion

    A survey on effects of shrimp aquaculture on the coastal waters of Bushehr (Helleh and Mond)

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    The effects of aquaculture industry on the environment were evaluated by studying the water quality of Bushehr costal water during culture season 2005 and 2006. The variations of selected parameters such as total phosphorus, ammonia, chlorophyll a, pH, salinity and... Were monitored in effluent canal, influent canal and open sea in Helleh and Mond regions as monthly. Following occurrence of White Spot Disease (W.S.D) in the shrimp ponds of Bushehr province, shrimp culture suspended and entrance of effluent waters completely were blocked since August 2005, despite the absence of aquaculture sewage evaluation of environment and sampling were continued. During releasing of sewage of shrimp ponds to the coastal waters of Bushehr in Jun 2005, the average amount of ammonia in Helleh and Mond were obtained to be 0.161 mg/l and 0.194 mg/l, however the average amount of total phosphorus in Helleh and Mond regions were 0.149 mg/l and 0.043 mg/l, respectively. Although effluent water suspension, amount of ammonia and total phosphorus were increased in both region especially in June 2006. Comparing present data in Jun 2005 and recorded data from culture period 1997-2003 with permitable range of municipal and aquaculture waste show that; aquaculture industry on both regions have not had any obvious negative effect on the coastal waters of Bushehr but it seems if other sources of pollutions in the region is not controlled, then the aquaculture industry can contribute to occurrence of environmental problems

    Empirical evaluation of microtremor H/V spectral ratio

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    The objective of this work is to perform a purely empirical assessment of the actual capabilities of the horizontal-to-vertical (H/V) spectral ratio technique to provide reliable and relevant information concerning site conditions and/or site amplification. This objective has been tackled through the homogeneous (re)processing of a large volume of earthquakes and ambient noise data recorded by different research teams in more than 200 sites located mainly in Europe, but also in the Caribbean and in Tehran. The original recordings were first gathered in a specific database with information on both the sites and recorded events. Then, for all sites close to an instrumented reference, average site-to-reference spectral ratios (“spectral ratio method” (SSR)) were derived in a homogeneous way (window selection, smoothing, signal-to-noise ratio threshold, averaging), as well as H/V ratios (“HVSRE–RF”) on earthquake recordings. H/V ratios were also obtained from noise recordings at each site (either specific measurements, or extracted from pre- or post-event noise windows). The spectral curves resulting from these three techniques were estimated reliable for a subset of 104 sites, and were thus compared in terms of fundamental frequency, amplitude and amplification bandwidth, exhibiting agreements and disagreements, for which interpretations are looked for in relation with characteristics of site conditions. The first important result consists in the very good agreement between fundamental frequencies obtained with either technique, observed for 81% of the analyzed sites. A significant part of the disagreements correspond to thick, low frequency, continental sites where natural noise level is often very low and H/V noise ratios do not exhibit any clear peak. The second important result is the absence of correlation between H/V peak amplitude and the actual site amplification measured on site-to-reference spectral ratios. There are, however, two statistically significant results about the amplitude of the H/V curve: the peak amplitude may be considered as a lower bound estimate of the actual amplification indicated by SSR (it is smaller for 79% of the 104 investigated sites), and, from another point of view, the difference in amplitude exhibits a questioning correlation with the geometrical characteristics of the sediment/basement interface: large SSR/HV differences might thus help to detect the existence of significant 2D or 3D effects.Published75-1084.1. Metodologie sismologiche per l'ingegneria sismicaJCR Journalreserve

    The monitoring of hydrology and hydrobiology stydies of the Persian Gulf in the Bushehr region

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    This study has been carried out in waters of Bushehr province in the Persian Gulf covering Nayband bay to Bahregansar between 26° 45 N to 30° 00 N and 49° 45 E to 52° 45 E, 15 main and 5 sub- stations, by R/V Ferdows 1 in winter 2004, summer 2004 and winter 2005. The physico - chemical parameters, nutrients (silicate, phosphate, nitrate and nitrite), phyto, zooplanktons, sediments and macrobenthoses were collected from water layers and sea bottom, and then analysed. The parameters were compared and evaluated with the results of the previous work, conducted in the same area. Termocline, halocline, oxycline and picnocline layers were formed in summer. These clins disappeared due to water column mixing in winter. The values of temperature, conductivity and pH in summer were higher than those of in winter, while the salinity and density values of surface and subsurface layers in winter were higher than those of in summer. The temperature and conductivity have been decreased from surface to depth, from coastal rigions to offshore and from southern waters to northwern waters, while salinity, density and turbidity have been increased. The dissolved oxygen is decreased by increasing the values of temperature, salinity and depth and it is observed that D.O. has increased in correlation with chlorophyl a in mean and subsurface layers. The pH was rather decreased from surface to depth while turbidity was increased. Orthosilicate (Si_SiO44), nitrate (N_NO3), and nitrite (N_NO2 ) concentration have increased from surface to depth while orthophostate (P_PO43) decreased. Among the phytoplanktons, Dinophycea had most abundance in winter 2004 and Diatoms had most abundance, variety and distribution in summer 2004 and winter 2005. Among the zooplanktons, Copeopda had most abundance, variety and distribution. The intensity of phytoplanktons in summer was more than those in winter; it decreased from surface to depth and from coastal rigions to offshore, at first increased and then gradually decreases. Intensity of zooplanktons in summer was more than those in winter and decreased from surface layers to depth and from coastal waters to offshore. The abundance of benthoses in summer was more than that in winter while their biomass in winter was more than that in summer. The abundance decreased from southern to northwern waters, but the rate of decrease in biomass was more than that of abundance. The mainly texture of sediments was loamy or muddy and the grain size in southeastern and northwestern areas were coarser than those in middle area. Compared with the previous study, the trend of physico chemical, silicate, nitrate and nitrite were the same but in spite of the past, the values of pH in summer were more than those in winter and also phosphate concentration had been decreased frome surface layer to depth. The overall trends of phyto and zooplanktons densities are almost similar to previous observation, but cyanophyceae significantly decreased, in comparison with spring and summer abundance. It is also observed that the zooplanktons average density has been in reverse order compared to previous observations. Average concentration of phosphate in the entire region was seven times more than that of the former study and its maximum value has rised more than 26 times in the petroleum and gas industries areas. On the other hand, the abundance and diversity of phyto and zooplanktons and also the ratio of biomass to abundance of benthoses were decreased
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