Introduction/purpose: When performing the explosive welding procedure, for the safety of workers, it is necessary to take into account the minimum distance between the workers and the place of ...explosion at the time of explosion. Negligence can cause temporary hearing loss, rupture of the eardrum and in some cases even the death of workers. The aim of this paper is to determine the critical distance based on the mass of explosive charge required for explosive welding, provided that the limit pressure is 6.9 kPa in the case of temporary hearing loss and 35 kPa in the case of eardrum rupture. This paper does not take into account other effects of the explosion than those caused by the shock wave. Methods: Depending on the type of explosion, the equivalent explosive mass was calculated. Based on the equivalent explosive mass and the limit pressure, the minimum distances were calculated using the Sadovsky and Kingery-Bulmash equations. Results: The corresponding tables show the results of the calculation of the critical distance of workers from the place of the explosion when there may be temporary hearing loss or rupture of the eardrum. The calculated value of the critical explosion distance by the Kingery-Bulmash method, under the condition of the maximum pressure for temporary hearing loss, is 5.62% lower than the distance value obtained by the Sadovsky method while the value of the critical explosion distance calculated by the Kingery-Bulmash method, under the condition of the maximum pressure for eardrum rupture, is 7.83% lower than the value obtained by the Sadovsky method. Conclusion: The results of the calculation showed that the critical distance from the explosion can be successfully calculated and that the obtained values have small differences depending on the applied calculation method.
This paper describes an optimization procedure for the adsorption of arsenite ions from wastewater using the Adaptive Neuro-Fuzzy Inference System (ANFIS). The adsorbent is based on hydroxy apatite, ...a natural material obtained from carp (Cyprinus carpio) scales. The input parameters were the influence of pH, the temperature, the initial concentration and reaction time of arsenite adsorption while the adsorption capacity and the arsenite removal percentage were studied as the output parameters. / В данной статье описана процедура оптимизации адсорбции ионов арсенита из сточных вод с использованием адаптивной нейронечеткой логической системы (ANFIS). В основе адсорбента лежит природный гидроксиапатитный материал, полученный из чешуи карпа (Cyprinus carpio). В качестве параметров ввода использовались влияние pH, температуры, начальной концентрации и времени реакции на адсорбцию арсенита, а в качестве выходных параметров были исследованы адсорбционная емкость и процент удаления арсенита. / U radu se opisuje postupak optimizacije adsorpcije arsenitnih jona iz otpadnih voda korišćenjem adaptivnog neuro-fazi sistema (ANFIS). U osnovi adsorbenta nalazi se prirodni hidroksi-apatitni materijal dobijen iz krljušti šarana (Cyprinus carpio). Kao ulazni parametri korišćeni su uticaj pH, temperature, početne koncentracije i vremena adsorpcije arsenita, a kao izlazni parametri ispitivani su adsorpcioni kapacitet i procenat uklanjanja arsenita.
In this study, the structure, morphology and composition of the synthesized
magnetite/3D-printed wollastonite (3D_W/M) composite were characterized, and
its adsorption performance with respect to ...As(V) and Cr(VI) were studied.
Magnetite (MG) modified 3D printed wollastonite was obtained by two step
procedure: modification of 3D_W with 3-aminoproylsilane (APTES) followed by
controlled magnetite (MG) deposition to obtain 3D_W/M adsorbent. The
structure/properties of 3D_W/M were confirmed by applying FTIR, XRD, TGD/DTA,
and SEM analysis. The adsorption properties of hybrid adsorbents were carried
out for As(V) and Cr(VI) removal - one relative to the initial pH value, the
adsorbent mass, the temperature, and the adsorption time. Time-dependent
adsorption study was best described by pseudo-second order equation, while
Weber Morris analysis showed that intraparticle diffusion controled
diffusional transport. Similar activation energy, 17.44 and 14.49 kJ?mol-1
for adsorption As(V) and Cr(VI) on 3D_W/M, respectively, indicated main
contribution of physical adsorption. Determination of adsorption parameters
was performed by applying different adsorption isotherm models, and the best
fit was obtained using Freundlich model. The adsorption capacity of 24.16 and
29.6 mg g-1 for As(V) and Cr(VI) at 2?C, Co = 5.5 and 5.3 mg L-1,
respectively, were obtained. Thermodynamic study indicated favourable process
at a higher temperature. Preliminary fixed-bed column study and results
fitting with Bohart-Adams, Yoon-Nelson, Thomas, and Modified dose-response
model showed good agreement with results from the batch study.
In this study, the structure, morphology and composition of the synthesized magnetite/3D-printed wollastonite (3D_W/M) composite were characterized, and its adsorption performance with respect to ...As(V) and Cr(VI) were studied. Magnetite (MG) modified 3D printed wollastonite was obtained by two step procedure: modification of 3D_W with 3-aminoproylsilane (APTES) followed by controlled magnetite (MG) deposition to obtain 3D_W/M adsorbent. The structure/properties of 3D_W/M were confirmed by applying FTIR, XRD, TGD/DTA, and SEM analysis. The adsorption properties of hybrid adsorbents were carried out for As(V) and Cr(VI) removal - one relative to the initial pH value, the adsorbent mass, the temperature, and the adsorption time. Time-dependent adsorption study was best described by pseudo-second order equation, while Weber Morris analysis showed that intraparticle diffusion controled diffusional transport. Similar activation energy, 17.44 and 14.49 kJ·mol-1 for adsorption As(V) and Cr(VI) on 3D_W/M, respectively, indicated main contribution of physical adsorption. Determination of adsorption parameters was performed by applying different adsorption isotherm models, and the best fit was obtained using Freundlich model. The adsorption capacity of 24.16 and 29.6 mg g-1 for As(V) and Cr(VI) at 2°C, Co = 5.5 and 5.3 mg L-1, respectively, were obtained. Thermodynamic study indicated favourable process at a higher temperature. Preliminary fixed-bed column study and results fitting with Bohart-Adams, Yoon-Nelson, Thomas, and Modified dose-response model showed good agreement with results from the batch study.
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