The safe environmental disposal of sulphide-rich copper/zine mine tailings is fast becoming a major economic factor in determining the profitability of mining operations. There have been new approaches and better technologies practised in the recent years which allow the mining industries to reduce and/or eliminate the environmental impacts of harmful mine tailings. One of these approaches is the use of high-density paste backfill (HDPB) which is consisting mainly of a mix of solid particles (with the cement) and water, containing between 70% and 85% by dry weight of solids. The increased use of HDPB has improved the reliability, and has reduced the cost of the preparation and transportation systems. This paper focuses on the potential environmental benefits of using the HDPB when tailings are acid generating, and also provides a case study conducted in an underground copper/zinc mine in northeast Turkey in order to illustrate these benefits.

The whitefly, Bemisia tabaci, an insect of the order Hemiptera which attacks more than 600 species of plants, is one of the most important agricultural pests around the world. The insecticidal Cry proteins from Bacillus thuringiensis (Bt) are useful biological pesticides, and some are toxic to Hemipteran insects. In this study, Colombian native isolates of Bt were functionally characterized at molecular and biological levels. The strains contained between one and five different crystal shapes: round, triangular, amorphous, bipyramidal and squared. The strains presented between three to seven bands of proteins in their electrophoretic pattern that were organized into six groups according to their possible biological activity on insect pests. Cry1Aa, cry1Ab, cry1Ac, cry1B and cry1C genes were identified for PCR in the different Bt isolates. Bioassays were performed on tomato leaves whose surface was spread with 3 μg · ml−1 crude extract of Bt toxins. Second instar larvae of whitefly, which were placed on top of leaves and exposed to the toxins for 7 days, exhibited mortalities from 18 to 69%. The lethal concentration 50 (LC50) of ZBUJTL39, Bt kurstaki HD1 and ZCUJTL9 strains were 1.83, 1.85 and 2.16 μg · ml−1, respectively (p < 0.05). These results show that the native Bt strain ZBUJTL39, which contained the genes cry1Aa, cry1Ab, cryCa and cryBa could eventually be used for the development of an integrated management program together with other tools for the control of B. tabaci.

This paper presents a non-invasive measurement method for simultaneous characterization of diameter and refractive index of transparent fibres. The method is based on scattering of a polychromatic beam of light by a side-illuminated fibre under study. Both quantities of interest are inversely calculated from the scattering far-field region in the vicinity of the primary rainbow. The results of practical measurements are examined with the use of a novel optical system for laboratory-level tests. An analysis of prediction errors for 20– 120 μm thick fibres having various refractive indices helps to assess the outcome of the measurement data. The results show a clear route to improve the measurement process in on-line industrial process control.

A new approach to passive electromagnetic modelling of coupled–cavity quantum cascade lasers is presented in this paper. One of challenges in the rigorous analysis of such eigenvalue problem is its large size as compared to wavelength and a high quality factor, which prompts for substantial computational efforts. For those reasons, it is proposed in this paper to consider such a coupled-cavity Fabry-Perot resonant structure with partially transparent mirrors as a two-port network, which can be considered as a deterministic problem. Thanks to such a novel approach, passive analysis of an electrically long laser can be split into a cascade of relatively short sections having low quality factor, thus, substantially speeding up rigorous electromagnetic analysis of the whole quantum cascade laser. The proposed method allows to determine unequivocally resonant frequencies of the structure and the corresponding spectrum of a threshold gain. Eventually, the proposed method is used to elaborate basic synthesis rules of coupled–cavity quantum cascade lasers.

Staphylococcus aureus (S. aureus) has been recognized as one of the important zoonotic pathogens. However, it was limited about the epidemiology and genetic characteristics of S. aureus isolated from pigs in Hunan province, china. The aim of this study was to determine the characteristics of 163 S. aureus isolated from 590 pigs in Hunan Province, China. All isolates were characterized by agr typing, detection of virulence genes and antibiotic resistance genes, lethal test of mice and antibiotic susceptibility tests. The results showed that 30 strains of the 163 isolates were divided into agrI (18.40%), agrII (36/163, 22.09%), agrIII (20/163, 12.27%,), agrIV (20/163,12.27%) and the remaining 57 isolates were amplified negative by agr primers. In the 163 isolates, the detection rate of the virulence genes hlb, hld, hla, icaA, seb, fnbA, eta, etb, sea, tst and pvl ranged from 2.45% to 100%. The 43 isolates that were lethal to the mice, had β-hemolytic activity, the number of virulence genes of which was 7.8% higher than that of the remaining 120 non-fatal strains. The resistance rates of the 163 isolates to the 15 antibiotics were 0% (0/163) - 100% (163/163). All isolates were susceptible to Vancomycin and only 7 isolates were methicillin - resistant S. aureus (MRSA). The detection rates of the 11 resistance genes was 0% (0/163) - 100% (163/163). This study first to describes the epidemiology and characteristics of S. aureus from pigs in Hunan Province, which will help in tracking the evolution of epidemic strains and preventing pig-human transmission events.

Characterization of sound absorbing materials is essential to predict its acoustic behaviour. The most commonly used models to do so consider the flow resistivity, porosity, and average fibre diameter as parameters to determine the acoustic impedance and sound absorbing coefficient. Besides direct experimental techniques, numerical approaches appear to be an alternative to estimate the material's parameters. In this work an inverse numerical method to obtain some parameters of a fibrous material is presented. Using measurements of the normal incidence sound absorption coefficient and then using the model proposed by Voronina, subsequent application of basic minimization techniques allows one to obtain the porosity, average fibre diameter and density of a sound absorbing material. The numerical results agree fairly well with the experimental data.

This work was carried out during two successive seasons (2016 and 2017) on cucumber fruits from a plastic greenhouse and from open field cultivation in El Gharbeia and El Giza Governorates, Egypt. Isolation trials from spoilage fruit samples of plastic greenhouse cultivation recorded high frequency of Alternaria tenusinium, Fusarium spp. and Pleospora alli. The most common fungi of rotten cucumber fruits from an open field were Galactomyces spp. and Fusarium spp. Pathogenicity tests proved that, Fusarium solani from El-Gharbeia followed by A. tenusinium from El-Giza were the most frequent isolates responsible for rot of cucumber fruits from plastic greenhouse cultivation. Moreover, the most frequent isolates causing postharvest disease of cucumber fruits of the open field were Galactomyces candidium from El-Giza followed by Geotrichum sp. and F. fujikuroi from El-Gharbeia Governorates, respectively. This is the first report of several fungi causing postharvest fruit rot disease of cucumber i.e., G. candidium, Geotrichum sp., A. tenusinium, P. alli and Fusarium spp. (F. fujikuroi, F. verticiolides, F. solani, F. geraminearium and Fusarium incarnatum). Fungal isolates were identified according to cultural, morphological and molecular characterization based on sequencing of internal transcribed spacer1 (ITS1). All the ITS nucleotide sequences of fungi were applied and conserved in GenBank.

The proposed paper discusses the design and characterization of a soft miniature Magneto-Rheological (MR) shock absorber. In particular, the final application considered for the insertion of the designed devices is a controllable variable stiffness sole for patients with foot neuropathy. Such application imposes particularly challenging constraints in terms of miniaturization (cross-sectional area ≤ 1.5 cm2, height ≤ 25 mm) and high sustainable loads (normal loads up to 60 N and shear stresses at the foot/device interface up to 80 kPa) while ensuring moderate to low level of power consumption. Initial design considerations are done to introduce and justify the chosen novel configuration of soft shock absorber embedding a MR valve as the core control element. Successively, the dimensioning of two different MR valves typologies is discussed. In particular, for each configuration two design scenarios are evaluated and consequently two sets of valves satisfying different specifications are manufactured. The obtained prototypes result in miniature modules (external diam. ≤ 15 mm, overall height ≤ 30 mm) with low power consumption (from a minimum of 63 mW to a max. of 110 mW) and able to sustain a load up to 65 N. Finally, experimental sessions are performed to test the behaviour of the realized shock absorbers and results are presented.

AISI 52100 bearing steels are commonly used in applications requiring high hardness and abrasion resistance. The bearing steels are

working under dynamic loads in service conditions and their toughness properties become important. In order to provide the desired

mechanical properties, various heat treatments (austenizing, quenching and tempering) are usually applied. In this study, AISI 52100

bearing steel samples were austenized at 900°C for ½ h and water quenched to room temperature. Then tempering was carried out at

795°C, 400°C and 200°C for ½ h. In order to investigate the effect of heat treatment conditions on wear behavior, dry friction tests were

performed according to ASTM G99-05 Standard with a ‘ball-on-disk’ type tribometer. The samples were tested against steel and ceramic

counterparts using the parameters of 100 m distance and 30 N load and 0.063 m/s rotational speed. After wear test, the surface

characterization was carried out using microscopy. Wear loss values were calculated using a novel optical method on both flat and

counterpart specimens.

In the present investigation, the morphology of Ti inclusions in high strength tire cord steel was investigated and their precipitation behavior was discussed using a precipitation and growth model. The results show that Ti inclusions mainly exist in the form of TiN. The two-dimensional characterization of Ti inclusions is square-like with sharp edges and corners, while its three-dimensional shape exhibits a cubic or rectangular-prism morphology. The Ti inclusions do not precipitate when the solid fraction of tire cord during solidification is less than 0.987, and their final radius is closely related to the cooling rate and initial concentration product. The higher the cooling speed, the smaller the final radius, when the cooling speed is constant, the final radius of Ti inclusions is mainly determined by the initial concentration product, w[N]0×w[Ti]0. In order to retard the precipitation and growth of Ti inclusions in tire cord steel, the cooling rate and initial concentration product can be taken into consideration.

In this paper, the authors investigated the size distribution of titanium oxide (TiO2), titanium nitride (TiN) and titanium carbide (TiC) inclusions in a titanium deoxidized 4130 steel and compared it with the 4130 base alloy composition inclusions. TiN and TiC inclusions are of particular interest due to their role as heterogeneous nuclei for various phase reactions in steels. Two types of samples were prepared, a polished sample and a filtered sample. Electrolytic dissolution was employed to make the filter paper samples. The size range of titanium inclusions was found to be more than that of the non-metallic inclusions from 4130 base alloy heat. Titanium inclusions from the filter and polished samples were round in shape. TiC and TiN inclusions were not found in the electrolytic extraction samples. Inclusions and their chemistries were analyzed using scanning electron microscope and energy dispersive spectrometer. The inclusion size range was larger for the titanium deoxidized samples than the base alloy. However, in both steels the majority of inclusions had a size smaller than 10 μm.

The proper interaction of bone tissue - the natural porous biomaterial - with a porous coated intra-osseous implant is conditioned, among others, by the implant porous coating poroaccessibility for bone tissue adaptive ingrowth. The poroaccessibility is the ability of implant porous coating outer layer to accommodate the ingrowing bone tissue filling in its pore space and effective new formed bone mineralizing in the pores to form a biomechanically functional bone-implant fixation. The functional features of the microtopography of intra-osseous implant porous surfaces together with the porosity of pore space of the outer layer of the porous coating are called by bioengineers the porostructural-osteoconductive properties of the porous coated implant. The properties are crucial for successful adaptive bone tissue ingrowth and further long-term (secondary) biomechanical stability of the boneimplant interface. The poroaccessibility of intra-osseous implants porous coating outer layers is characterized by - the introduced in our previous papers - set of stereometric parameters of poroaccessibility: the effective volumetric porosity fVef, the index of the porous coating space capacity VPM, the representative surface porosity fSrep, the representative pore size pSrep, the representative angle of the poroaccessibility Wrep and the bone-implant interface adhesive surface enlargement index y. Presented in this paper, an original method of evaluation of the porostructural-osteoconductive properties of intra-osseous implant porous coatings outer layer by means of the parameters of poroaccessibility was preliminary verified during experimental tests performed on the representative examples of porous coated femoral stems and acetabular cups of various hip endoprostheses. The computer-aided stereometric evaluation of the microstructure of implant porous coatings outer layer can be now realized by the authoring application software PoroAccess_1.0 elaborated in our research team in Java programming language

In the paper a method using active thermography and a neural algorithm for material defect characterization is presented. Experimental investigations are conducted with the stepped heating method, so-called time-resolved infrared radiometry, for the test specimen made of a material with low thermal diffusivity. The results of the experimental investigations were used in simulations of artificial neural networks. Simulations are performed for three datasets representing three stages of the heating process occurring in the investigated sample. In this work, the simulation research aimed to determine the accuracy of defect depth estimation with the use of the mentioned algorithm is descibed

This work reports the results of a study of Mo thin films synthesis by DC Pulsed Magnetron Sputtering method (PMS), operating at pulse main frequency of 100 kHz and modulated by the additional modulation frequency, driving in the range of 5-1000 Hz (modulated Pulse Magnetron Sputtering – mPMS). We have studied the influence of mPMS on plasma chemical reactions and mechanisms of layer growth using optical emission spectroscopy technique. Our experiment showed strong influence of mPMS method, on the morphology (scanning electron microscopy), phase composition (X-ray diffractometry) and electric properties (4-point probes method) of nanocrystalline and amorphous Mo films. From the utilitarian point of view, low value of resistivity – 43,2 μΩcm of synthesized Mo films predestines them as back contacts for thin solar cells CIGS. Our results revealed that additional modulation frequency should be considered as an important factor for optimization of films synthesis by means of PMS-based methods.

Photonic devices often use light delivered by a single-mode telecommunication fibre. However, as the diameter of the core of the optical fibre is of 10 microns, and the transverse dimensions of the photonic waveguides are usually micrometer or less, there is an issue of incompatibility. The problem may be solved by application of tapered optical fibres. For efficient light coupling, the taper should be prepared so as to create a beam of long focal length and small spot diameter in the focus. The article describes the design, fabrication and characterization of tapered optical fibres prepared with a fibre-optic fusion splicer. We modelled the tapers with FDTD method, for estimation of the influence of the tapered length and angle on the spot diameter and the focal length of an outgoing beam. We fabricated tapers from a standard single mode fibre by the Ericsson 995 PMfi- bre-optic fusion splicer. We planned the splicing technology so as to get the needed features of the beam. We planned a multistep fusion process, with optimized fusion current and fusion time. The experimental measurements of best tapered optical fibres were carried out by the knife-edge method.

We describe a new method to separate ballistic from the scattered photons for optical tissue characterization. It is based on the hypothesis that the scattered photons acquire a phase delay. The photons passing through the sample without scattering or absorption preserve their coherence so they may participate in interference. We implement a Mach−Zehnder experimental setup where the ballistic photons pass through the sample with the delay caused uniquely by the sample indices of refraction. We incorporate a movable mirror on the piezoelectric actuator in the sample arm to detect the amplitude of the modulation term. We present the theory that predicts the path−integrated (or total) concentration of the scattering and absorption centres. The proposed technique may characterize samples with transmission attenuation of ballistic photons by a factor of 10^-14.