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Abstract

Stemming plugs are one of the widely used accessory in surface mining operations. Stemming plugs assist conventional stemming material in gas retention and help in better fragmentation and explosive utilization. Effective use of the stemming plugs results in economic benefits and enhance the efficacy of the project. Economic and productive viability of stemming plugs have been conducted in depth by different researchers. Addition of stemming plugs to a new system requires ergonomic challenges for operators conducting drilling and blasting operation. Induction of a newer product in already established system is subject to overall positive feedback. This work investigates ergonomics of three different stemming plugs introduced to a limestone quarry in Pakistan. The stemming plugs were evaluated based on extra time needed, workers feedback, failures during operation, recovery time after failure and number of extra equipment required to carry out the operation. Points based matrix was established with likeliness of each plug and based on overall scores stemming plug 1 was most acceptable followed by stemming plug 3. Stemming plug 2 was disliked by operation and did not reach the level of acceptability of operators. This work will help stemming plug making industry in adapting to best practices by incorporating ergonomics of plugs in designing. Literature shows no previous work on ergonomics of stemming plugs.

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Authors and Affiliations

Atta Ur Rehman
Muhammad Zaka Emad
Muhammad Usman Khan
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Abstract

Geothermal waters are a source of clean energy. They should be used in a rational manner especially in energyand economic terms.

Key factors that determine the conditions in which geothermal waters are used, the amount of energy obtainedand the manner in which cooled water is utilised include water salinity. Elevated salinity levels and the presence oftoxic microelements may often lead to difficulties related to the utilisation of spent waters. Only a few Polishgeothermal facilities operate in a closed system, where the water is injected back into the formation after havingbeen used. Open (with water dumped into surface waterways or sewerage systems) or mixed (only part of the wateris re-injected into the formation via absorption wells while the rest is dumped into rivers) arrangements are morefrequently used. In certain circumstances, the use of desalinated geothermal water may constitute an alternativeenabling local needs for fresh water to be met (e.g. drinking water).

The assessment of the feasibility of implementing the water desalination process on an industrial scale islargely dependent on the method and possibility of disposing of, or utilising, the concentrate. Due to environmentalconsiderations, injecting the concentrate back into the formation is the preferable solution. The energy efficiency and economic analysis conducted demonstrated that the cost effectiveness of implementing the desalinationprocess in a geothermal system on an industrial scale largely depends on the factors related to its operation,including without limitation the amount of geothermal water extracted, water salinity, the absorption parameters ofthe wells used to inject water back into the formation, the scale of problems related to the disposal of cooled water,local demand for drinking and household water, etc. The decrease in the pressure required to inject water into theformation as well as the reduction in the stream of the water injected are among the key cost-effectiveness factors.Ensuring favourable desalinated water sale terms (price/quantity) is also a very important consideration owing tothe electrical power required to conduct the desalination process

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Authors and Affiliations

Barbara Tomaszewska
ORCID: ORCID
Leszek Pająk
ORCID: ORCID
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Abstract

The development of economic and efficient processes for the removal of toxic metals from water bodies has become a priority task for environmentalists. Biosorption processes are tangible alternatives to traditional methodologies, particularly if low metal concentration, large volume and cost are considered. The present communication reports the unexploited sorption properties of the Saraca indica leaf powder (SILP) for the removal of Cd(II) and Ni(II) from aqueous media. Sorption studies using standard practices were carried out in batch experiments as a function of biomass dosage, metal concentration, contact time, particle size and pH. Sorption studies result into the standardization of optimum conditions for the removal of Cd(II) - 92.60% and Ni(II) - 46.20% as follows: biomass dosage (4.0 g), metal concentration (Cd(II) 10 μg/cm3, Ni(ll) 10 μg/cm3) and volume of the test solution (200 cm') at pH 6.5 for Cd(II) and Ni(II). The present study explores for the first time, the efficacy of Saraca indica leaf powder as a novel and environment friendly possibility to remediate heavy metal contaminated water in a cost efficient manner.
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Authors and Affiliations

M.M. Srivastava
Aditya Chauhan
Pushpa Kumari
Parul Sharma
Shalini Srivastava
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Abstract

The sedimentation devices are commonly used in the clarifying of industrial suspensions and in the civil engineering. The sedimentation efficiency plays very important role in the environmental protection. The aim of the research was to investigate the possibilities of applying neural networks in computing the efficiency of sedimentation processes. Input data were the results of computer stimulation performed according to the mathematical model taking into account the overflow rate in the sedimentation facilities and physical parameters of the suspension, such as probability density function of solid particle size. Two probability density functions of solid particle size were compared: log-normal distribution and gamma distribution. Feed-forward neural networks (with no feedback and with one- stream flow of information) were applied in research work. Teacher-supervised teaching, according to back-propagation method with the use of Levenberg-Marquardt algorithm, was chosen. When neural networks were taught with the use of sets including less than 400 data elements, the errors were more than I%. Neural networks taught by means of series including more than 500 data sets would yield acceptable results and the error was less than I%. Accordingly, one can presume that the smallest teaching set is the one composed of 500 data elements. The best results were obtained when the number of data sets was about 5000- the differences in computed sedimentation efficiency were then less than 0.5%. A further increase in the number of data elements - above 5000 - would lead to lower accuracy of calculations.
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Authors and Affiliations

Włodzimierz P. Kowalski
Krzysztof Kołodziejczyk
Tomasz Zacharz
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Abstract

Peak-to-average power ratio reduction techniques for visible light communication broadcasting systems are designed, simulated, and evaluated in this work. The proposed techniques are based on merging non-linear companding techniques with precoding techniques. This work aims to nominate an optimum novel scheme combining the low peak-to-average power ratio with the acceptable bit error rate performance. Asymmetrically clipped optical orthogonal frequency division multiplexing with the low peak-to-average power ratio performance becomes more attractive to real-life visible light communication applications due to non-linearity elimination. The proposed schemes are compared and an optimum choice is nominated. Comparing the presented work and related literature reviews for peak-to-average power ratio reduction techniques are held to ensure the proposed schemes validity and effectiveness.
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Authors and Affiliations

Nazmi A. Mohammed
1
Mohamed M. Elnabawy
2 3
Ashraf A. M. Khalaf
2
ORCID: ORCID

  1. Photonic Research Lab, Electrical Engineering Department, College of Engineering, Shaqra University, Dawadmi 11961, Kingdom of Saudi Arabia
  2. Electrical Engineering Department, Faculty of Engineering, Minia University, Minia, Egypt, P.O. Box 61111, Minia, Egypt
  3. Electronics and Communication Department, Modern Academy for Engineering and Technology, Maadi 11585, Cairo, Egypt
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Abstract

The research was set up in the Neretva River valley in the Southern part of Croatian Karst area, where implementation of modern hydrotechnical practices within the river catchment’s area led to intrusion of seawater to groundwater resulting in soil salinization in the delta. The region has great agro-ecological potential for intensive production of vegetables and Mediterranean fruits. Since the combination of the effects of saline groundwater and the use of this water for irrigation may have disastrous effects on the productivity of agricultural soils water, a project was started in order to set up a permanent monitoring network. The aim of this study was to determine the salt dynamics in the surface water on five locations which are considered as potential sources of the irrigation water (Modric canal, Neretva River near Opuzen, Crepina, Jasenska and Vidrice pumping station) during a 4-year period (1999–2002). The surface water samples had been collected on monthly basis and analyzed for all parameters required in the irrigation water quality classification. The results show considerable spatial and temporal variability of determined parameters. Thus, in the Neretva River near Opuzen, total salt concentrations in water ranged from 0.4 to 7.7 dS·m–1, and in Modric from 1.65 up to17.2 dS·m–1. Dominant cations and anions on all observed locations were Na+ and Cl–. Constantly high concentration of Na+ in sampled surface waters is of a special concern. Utilization of the water of such quality may cause problems related to the use of alkaline waters for irrigation, which can further cause permanent loss of fertile soil.

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Authors and Affiliations

Davor Romić
Monika Zovko
Marija Romić
Gabrijel Ondrašek
Zoran Salopek
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Abstract

The smart city concept is constantly evolving. More and researchers in Poland and also in the whole world deal with this issue. In practice, it is noted that in cities around the world you can find more and more implemented projects referred as smart, in particular in Barcelona, Vienna and Copenhagen and others. According to the classical definition, smart city means introducing solutions based on the latest information technologies to urban spaces in order to improve the quality of life of city residents. Smart city is a city concept in which solutions can solve the most important problems related to the functioning of cities, such as improvements in public transport and goods in cities, counteracting climate change through the use of energy-saving solutions of city lighting, social inclusion (access city) and others. The concept of smart city is based on IT solutions that are constantly modernized and adapted to specific needs of individual cities. By using real-time access to information, they help make more efficient decisions for city users. However, recent approaches highlight the relationship between modern network technologies and the urban community. One can notice the focus of the researchers on the relational approach, which means combining the smart city concept with the participation of residents in the city management process, and in particular making choices and implementing smart projects. In this sense, the smart city idea defines the way of managing a city in which relations between the self-government, IT providers and science as well as the inhabitants of the city are particularly important. Responding to the needs of residents is particularly important as counteracting the tendency to focus smart products and services in richer places and create socalled an innovation hub with the simultaneous periphery of the remaining districts. Criticism of the smart city concept focuses on the problem of the social polarization of cities, in which the technological revolution contributes more to the increase of socio-economic disparities rather than their decreasing. The aim of the article is to answer the question whether the implementation of the smart city concept polarizes the urban community and does it allow the inclusive development of cities?

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Authors and Affiliations

Małgorzata Pięta-Kanurska
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Abstract

Changes in activity of amylase, cellulase, protease and dehydrogenase during biodegradation of petroleum contaminants were investigated in laboratory studies. Refinery soil polluted for a long time was modified by commercial biological preparation and natural biological preparation (prepared from this soil). These modifications did not influence cellulase and protease activity. Activity of amylase and dehydrogenase changed in these samples. In the sixth week the highest activity of dehydrogenase was noticed, especially in soil with commercial biological preparation. Modifications had a great influence on contaminants degradation. The highest elimination of TPH (20,4%) and heavy fractions (10,5%) took place in soil modified by commercial biological preparation. The highest PAH elimination was in soil with natural bacterial preparation
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Authors and Affiliations

Wioletta Przystaś
Korneliusz Miksch
Anna Małachowska-Jutsz
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Abstract

A novel method for thermal diffusivity evolution of thin-film materials with pulsed Gaussian beam and infrared video is reported. Compared with common pulse methods performed in specialized labs, the proposed method implements a rapid on-line measurement without producing the off-centre detection error. Through mathematical deduction of the original heat conduction model, it is discovered that the area s, which is encircled by the maximum temperature curve rTMAX(θ), increases linearly over elapsed time. The thermal diffusivity is acquired from the growth rate of the area s. In this study, the off-centre detection error is avoided by performing the distance regularized level set evolution formulation. The area s was extracted from the binary images of temperature variation rate, without inducing errors from determination of the heat source centre. Thermal diffusivities of three materials, 304 stainless steel, titanium, and zirconium have been measured with the established on-line detection system, and the measurement errors are: −2.26%, −1.07%, and 1.61% respectively.

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Authors and Affiliations

Huilong Dong
Boyu Zheng
Feifan Chen

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