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1

Minimising backbreak at the Dewan Cement limestone quarry using an artificial neural network

Muhammad K., Shah A.

Archives of Mining Sciences

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2017

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Vol. 62, no. 4

795--806

EN

Backbreak, defined as excessive breakage behind the last row of blastholes in blasting operations at a quarry, causes destabilisation of rock slopes, improper fragmentation, minimises drilling efficiency. In this paper an artificial neural network (ANN) is applied to predict backbreak, using 12 input parameters representing various controllable factors, such as the characteristics of explosives and geometrical blast design, at the Dewan Cement limestone quarry in Hattar, Pakistan. This ANN was trained with several model architectures. The 12-2-1 ANN model was selected as the simplest model yielding the best result, with a reported correlation coefficient of 0.98 and 0.97 in the training and validation phases, respectively. Sensitivity analysis of the model suggested that backbreak can be reduced most effectively by reducing powder factor, blasthole inclination, and burden. Field tests were subsequently carried out in which these sensitive parameters were varied accordingly; as a result, backbreak was controlled and reduced from 8 m to less than a metre. The resulting reduction in powder factor (kg of explosives used per m3 of blasted material) also reduced blasting costs.

PL

Kruszenie części złoża poza obszarem prowadzonych prac strzałowych oznacza nadmierne pękanie skał poza ostatnim rzędem otworów strzałowych w trakcie prac w kamieniołomach i prowadzi do destabilizacji górotworu poprzez zmianę nachylenia warstw skalnych, powoduje niepotrzebną fragmentację skał i obniża efektywność prac wiertniczych. W pracy tej wykorzystano sztuczną sieć neuronową (ANN) do przewidywania zasięgu kruszenia dalszej części złoża przy wykorzystaniu 12 parametrów wejściowych. Parametry te opisują różne zmienne czynniki, np. charakterystyka materiału wybuchowego czy przyjęty plan prac strzałowych w kamieniołomie Deewan w regionie Hattar w Pakistanie. Prowadzono proces uczenia sieci dla różnej architektury modelu, wybrano model 12-2-1 ANN, jako model najprostszy, zapewniający najlepszy wynik a współczynniki korelacji uzyskane dla fazy uczenia i walidacji wyniosły odpowiednio 0.98 i 0.97. Przeprowadzona analiza wrażliwości modelu wykazała że zasięg kruszenia dalszych części złoża obniżyć można poprzez zmianę parametrów ładunku strzelniczego, zmianę nachylenia otworów strzałowych oraz zmianę przybitki. Badania terenowe w czasie których ulegały zmianie wartości wyżej wymienionych wrażliwych parametrów wykazały, że zasięg kruszenia złoża poza obszarem prac strzałowych ograniczono z uprzednich 8 m do wielkości poniżej jednego metra. Obniżenie współczynnika charakteryzującego ładunek (kg zastosowanego materiału wybuchowego przypadający na 1 m3 rozkruszonego materiału skalnego) pozwoliło także na obniżenie kosztów prac strzałowych.

2

Optical spectroscopic analysis of annealed Cd1−xZnxSe thin films deposited by close space sublimation technique

Ali I., Iqbal A., Mahmood A., Shah A., Zakria M., Ali A.

Materials Science Poland

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2016

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Vol. 34, No. 4

828--833

EN

Cd1−xZnxSe (x = 0, 0.40 and 1) thin films were deposited on a glass substrate at room temperature by closed space sublimation method. Optical investigation has been performed using spectrophotometry and ellipsometry. It has been found that for as deposited films the optical band gap increased and the optical constants decreased with increasing Zn content. To improve the optical properties of Cd1−xZnxSe thin films annealing effect at 400 °C was taken into consideration for various Zn contents. It was observed that the optical transmittance and band gap decreased while optical constants increased with increasing Zn content after annealing. The effects of composition and annealing on the optical dispersion parameters Eo and Ed were investigated using a single effective oscillator model. The calculated value of the average excitation energy Eo obeys the empirical relation (Eo = Eg/2) obtained from the single oscillator model.

3

CAC DPLB MCN: A Distributed Load Balancing Scheme in Multimedia Mobile Cellular Networks

Sharma A., Shah A., Chatterjee M., Bhattacharya U.

Foundations of Computing and Decision Sciences

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2016

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Vol. 41, No. 4

261--296

EN

The problem of non-uniform traffic demand in different cells of a cellular network may lead to a gross imbalance in the system performance. Thus, the users in hot cells may suffer from low throughput. In this paper, an effective and simple load balancing scheme CAC_DPLB_MCN is proposed that can effectively reduce the overall call blocking. This model considers dealing with multi-media traffic as well as time-varying geographical traffic distribution. The proposed scheme uses the concept of cell-tiering thereby creating fractional frequency reuse environment. A message exchange based distributed scheme instead of centralized one is used which help the proposed scheme be implemented in a multiple hot cell environment also. Furthermore, concept of dynamic pricing is used to serve the best interest of the users as well as for the service providers. The performance of the proposed scheme is compared with two other existing schemes in terms of call blocking probability and bandwidth utilization. Simulation results show that the proposed scheme can reduce the call blocking significantly in highly congested cell with highest bandwidth utilization. Use of dynamic pricing also makes the scheme useful to increase revenue of the service providers in contrast with compared schemes.

4

Implementation of Server virtualization to Build Energy Efficient Data Centers

Uddin M., Shah A., Abubakar A., Adeleke I.

Journal of Power Technologies

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2014

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Vol. 94, nr 2

85--94

EN

The rapid growth in the size and capacity of data centers driven by a continual rise in the number of servers and other IT equipment is causing an exponential increase in the demand for power. All data centers are plagued by the operational presence of thousands of servers as major components. These servers consume a huge amount of power while performing little in terms of useful work. In an average server environment, 30% of servers are “zombies”- they merely consume power while having a utilization ratio of only 5 to 10 %. Server virtualization contributes to this problem by offering an opportunity to consolidate multiple underutilized volume servers into a single physical server, thereby reducing the physical and environmental footprint of data centers. This paper suggests implementing “server virtualization” to achieve energy efficient data centers. The proposed technique increases the utilization ratio of underutilized servers up to 50%, saving a huge amount of power and at the same time reducing the emission of greenhouse gases.

5

Synthesis and characterization of some new Schiff bases of 2-oxonaphtho[2,1-b][1,4]oxazine

Chovatiya P., Mehta C., Senjani H., Shah A., Joshi H. S.

International Letters of Chemistry, Physics and Astronomy

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2014

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Vol. 12

26--30

EN

The literature review reveal that [1,4]-oxazine derivatives represent one of the most active classes of compounds possessing wide spectrum of biodynamic activities and use as potent therapeutic agents. In the present work, a series of Schiff base of 2-(2,3-dihydro-2-oxonaphtho[2,1-b][1,4]oxazin-1-yl)acetohydrazide, 5a-5j has been synthesized using 1-aminonaphthalen-2-ol. Various aromatic aldehyde were react with carbohydrazide 4 in the presence of acid to produce the 2-oxonaphtho[2,1-b][1,4]oxazin Schiff base derivatives with good yields. All synthesized compounds were characterized by IR, NMR and Mass spectrometry analysis.

6

Synthesis and antimicrobial activity of coumarinyl Schiff base derivatives

Mishra A., Rathod J., Namera D., Thakrar S., Shah A.

International Letters of Chemistry, Physics and Astronomy

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2014

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Vol. 11, iss. 3

193--201

EN

We have reported some novel N’-[(1)-ethylidene]-2-(6-methyl-2-oxo-2H-chromen-4-yl) acetohydrazide synthesized by conventional method. The reaction of 2-(6-methyl-2-oxo-2H-chromen-4-yl)acetohydrazide with substituted benzaldehyde in methanol as a solvent yielded a series of (7a-l). The structures of all synthesized compounds are well characterized by Mass, FT-IR, 1H NMR, 13C NMR and elemental analysis. Moreover, all synthesized compounds were screened for in vitro antimicrobial activity against the gram positive (Staphylococcus aureus, Bacilluas subtilis) and gram negative (Escherichia coli, P. aeruginosa, K. pneunonae, Enterobacter) bacterial strain. In which some the compounds show potential inhibition against the test organisms.

7

Novel conversion of 4-aminoquinolines to new tricyclic (R,S)-3-methylazeto[3,2-c] quinolin-2(2aH)-ones and versatile one step synthesis of N-(quinolin-4-yl) carbamates from 4-aminoquinolines

Kotadiya V. C., Viradiya D. J., Baria B. H., Kanzariya J. S., Kakadiya R., Shah A.

International Letters of Chemistry, Physics and Astronomy

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2014

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Vol. 11, iss. 3

265--276

EN

Reaction of 4-aminoquinolines with 4-nitrophenyl chloroformate have resulted in finding a novel transformation of 4-aminoquinolines to tricyclic (R,S)-3-methylazeto[3,2-c]quinolin-2(2aH)-ones. The structure of azeto-quinolinone was determined via spectroscopic and chemical methods. Various alcohols were used as nucleophiles to open the 1-azetinone ring to give the corresponding N-(quinolin-4-yl)carbamates in good yields. We also found a new and versatile one step synthesis of N-(quinolin-4-yl)carbamates by reacting 4-aminoquinolines with alkyl chloroformates in the presence of anhyd K2CO3 in acetonitrile.

8

Highly efficient and eco-friendly one-pot synthesis of penta substitute pyrrole derivatives under catalyst-free conditions

Viradiya D. J., Baria B. H., Kakadiya R., Kotadiya V. C., Shah A.

International Letters of Chemistry, Physics and Astronomy

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2014

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Vol. 11, iss. 3

257--264

EN

An eco-friendly and efficient one-pot synthesis of penta-substituted pyrrole derivatives via a four-component reaction of maldrum’s acid, arylglyoxal monohydrate, dimethyl but-2-yne-dioate and amines under catalyst-free conditions in an environmentally friendly medium is described. The simple experimental procedure, catalyst-free reaction conditions, short period of conversion, and excellent yields are the advantages of the present method. Good chemical yields have been achieved without the need for chromatography and recrystallization or other purification methods.

9

Acid-Promoted Synthesis of Imidazolyl-Pyrazole Derivatives via a Multicomponent Reaction Using Ultra Sound Irradiation

Baria B., Viradiya D., Kotadiya V., Kakadiya R., Shah A.

International Letters of Chemistry, Physics and Astronomy

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2014

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Vol. 11, iss. 3

277--283

EN

Some new imidazolyl pyrazole derivatives have been synthesized using benzil, ammonium acetate, and heterocyclic aldehyde in ethanol and acetic acid under ultra sound irradiation. The obtained products using this approach are having high purity and good in yield. By conducting the reactions in ethanol, the solid products were precipitated out and could be isolated simply by filtration. The synthesized compounds were characterized by various analytical techniques such as 1H and 13C NMR and further supported by mass spectroscopy.

10

Photocatalytic Degradation of Crystal Violet by Use of Copper Oxide as Semiconductor

Shah A., Mittal N., Bhati I., Sharma V. K., Punjabi P. B.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 11

2001-2007

EN

The photocatalytic degradation of crystal violet on copper oxidesemi conductor suspended in aqueous solution has been carried out. The progress of reaction has been studied spectrophotometrically by observing absorbance of reaction mixture at different time intervals. The effects of various parameters such as concentration of crystal violet, pH of reaction mixture amount of semiconductor and intensity of light on the rate of reaction have also been observed. The photocatalytic degradation of crystal violet follows pseudo first order kinetics and the rate constant has been determined. Atentative mecha nism for the reaction has also been proposed.