Leaching of a zinc ore and concentrate using the Geocoat™ technology

In this study, the Geocoat™ technology was used for the extraction of zinc from a mineral concentrate obtained from the Kooshk mine (Yazd, Iran) by a culture dominated by the mesophilic bacterium Acidithiobacillusferrooxidans in a packed column bioreactor. A low grade sphalerite ore was used as support for the concentrate coating. During the 100 days of leaching pH, Fe³⁺, Fe^total, microbial population density and zinc extraction were measured. The final zinc extraction from concentrate and low grade support was 97% and 78%, respectively, and it was found that leaching from the support does not proceed significantly before leaching from the coating is completed.     

CMOS interface circuitry for a low-voltage micromachined tunnelingaccelerometer

This paper describes the design and development of three types of complementary metal-oxide-semiconductor (CMOS) interface circuitry for low-voltage micromachined tunneling accelerometers. Using a simple inductance-capacitance-resistance (LCR) circuit as well as two nonlinear current/voltage-controlled current sources, an electromechanical model enables simulating and predicting the performance of the accelerometer with CMOS interface circuitry. Of the three types of interface circuitry, the one utilizing a pn-junction diode as a logarithmic current-to-voltage converter has the best performance. The hybrid sensor-circuit module can be incorporated into a portable battery-operated multisensor instrumentation microsystem. Only one 12-V power supply is required for device operation with a power dissipation of 2.5 mW. The accelerometer has a sensitivity of 125 mV/g and bandwidth of 2.5 kHz with a measurement range of 30 g. The noise spectral density with a 1/f behavior drops from 4 mg/√(Hz) (at 0.5 Hz) to 0.1 mg/√(Hz) (at 2.5 kHz). The accelerometer in turn provides a dynamic range over 71 dB with a minimum detectable acceleration of 8 mg in a bandwidth of 2.5 kHz. In continuous operation over 720 h, the long-term variations of the output offset voltage and device sensitivity are ±10 mV (0.12%) and ±0.2 mV/g (0.15%), respectively     

Length optimization of single-mode rare-earth doped waveguidesusing saturated absorption

Absorption saturation was demonstrated to provide a high, uniform population inversion over a length of waveguide longer than the material absorption length. The small signal gain was measured experimentally in single-mode waveguides, made by silver ion exchange, on a commercially available neodymium doped glass. The ratio of the excited states was calculated as a function of waveguide length and was shown to be a convenient criteria to determine the optimum device length     

Silicon Affects Rice Growth,Superoxide Dismutase Activity and Concentrations of Chlorophyll and Proline under Different Levels and Sources of Soil Salinity

Silicon - Silicon (Si) application shows beneficial effects on growth and salt tolerance of plants; however, its effects on the rice (Oryza sativa L. var. Hashemi) growth, superoxide dismutase...     

Production of angiotensin-converting enzyme inhibitory peptides in Iranian ultrafiltered white cheese prepared with Lactobacillus brevis KX572382

In this study, ultrafiltered (UF) Iranian white cheese made with adjunct cultures including six Lactobacillus isolates (Lactobacillus brevis, L. casei and L. plantarum) from traditional Iranian Motal cheese. The peptide extract (<5 kDa) of cheese samples were assessed for angiotensin-converting enzyme (ACE)-inhibitory activity during ripening (5 °C). Among the strains used, L. brevis KX572382 (M8) was selected because of the greater increase in (ACE)-inhibitory activity in the cheese (P < 0.05). The highest activity of M8 extract was observed on the 28th (71.72%) day of ripening (P < 0.05). Proteolytic activity assessment and RP-HPLC peptide profile of M8 water-soluble extracts (WSEs) indicated the effect of M8 on further protein degradation due to secondary proteolysis. A total of 7 different peptide sequences, previously known in the literature for their ACE-inhibitory activity, were tentatively identified by LC/ESI-MS in 28-day M8 peptide extract. Although the effect of M8 on pH and the proteolysis development in cheese was significant, no adverse effect was observed on the sensory properties. In conclusion, M8 strain can enhance the functional properties of Iranian UF white cheese.     

Solution‐Processed GaSe Nanoflake‐Based Films for Photoelectrochemical Water Splitting and Photoelectrochemical‐Type Photodetectors

Gallium selenide (GaSe) is a layered compound, which has been exploited in nonlinear optical applications and photodetectors due to its anisotropic structure and pseudodirect optical gap. Theoretical studies predict that its 2D form is a potential photocatalyst for water splitting reactions. Herein, the photoelectrochemical (PEC) characterization of GaSe nanoflakes (single‐/few‐layer flakes), produced via liquid phase exfoliation, for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in both acidic and alkaline media is reported. In 0.5 m H₂SO₄, the GaSe photoelectrodes display the best PEC performance, corresponding to a ratiometric power‐saved metric for HER (Φ_saved,HER) of 0.09% and a ratiometric power‐saved metric for OER (Φ_saved,OER) of 0.25%. When used as PEC‐type photodetectors, GaSe photoelectrodes show a responsivity of ≈0.16 A W^?1 upon 455 nm illumination at a light intensity of 63.5 µW cm^?2 and applied potential of ?0.3 V versus reversible hydrogen electrode (RHE). Stability tests of GaSe photodetectors demonstrated a durable operation over tens of cathodic linear sweep voltammetry scans in 0.5 m H₂SO₄ for HER. In contrast, degradation of photoelectrodes occurred in both alkaline and anodic operation due to the highly oxidizing environment and O₂‐induced (photo)oxidation effects. The results provide new insight into the PEC properties of GaSe nanoflakes for their exploitation in photoelectrocatalysis, PEC‐type photodetectors, and (bio)sensors.     

Optical Imaging Approaches to Monitor Static and Dynamic Cell‐on‐Chip Platforms: A Tutorial Review

Miniaturized laboratories on chip platforms play an important role in handling life sciences studies. The platforms may contain static or dynamic biological cells. Examples are a fixed medium of an organ‐on‐a‐chip and individual cells moving in a microfluidic channel, respectively. Due to feasibility of control or investigation and ethical implications of live targets, both static and dynamic cell‐on‐chip platforms promise various applications in biology. To extract necessary information from the experiments, the demand for direct monitoring is rapidly increasing. Among different microscopy methods, optical imaging is a straightforward choice. Considering light interaction with biological agents, imaging signals may be generated as a result of scattering or emission effects from a sample. Thus, optical imaging techniques could be categorized into scattering‐based and emission‐based techniques. In this review, various optical imaging approaches used in monitoring static and dynamic platforms are introduced along with their optical systems, advantages, challenges, and applications. This review may help biologists to find a suitable imaging technique for different cell‐on‐chip studies and might also be useful for the people who are going to develop optical imaging systems in life sciences studies.     

Influence of nanoclay on urea–glyoxalated lignin–formaldehyde resins for wood adhesive

In this research, the influence of nanoclay on urea–glyoxalated lignin–formaldehyde (GLUF) resin properties has been investigated. To prepare the GLUF resin, glyoxalated soda baggase lignin (15 wt%) was added as an alternative for the second urea during the UF resin synthesis. The prepared GLUF resin was mixed with the 0.5%, 1%, and 1.5% nanoclay by mechanically stirring for 5 min at room temperature. The physicochemical properties of the prepared resins were measured according to standard methods. Then the resins were used in particleboard production and the physical and mechanical properties of the manufactured panels were determined. Finally, from the results obtained, the best prepared resin was selected and its properties were analyzed by differential scanning calorimetry (DSC), Fourier transform infrared spectrometry (FTIR), and X-ray diffractometry (XRD). Generally the results indicated that the addition of sodium-montmorillonite (NaMMT) up to 1.5% appears to improve the performance of GLUF resins in particleboards. The results also showed that nanoclays improved mechanical strength (modulus of elasticity (MOE), Modulus of Rupture (MOR), and internal bond (IB) strength) of the panels bonded with GLUF resins. The panels containing GLUF resin and nanoclay yielded lower formaldehyde emission as well as water absorption content than those made from the neat GLUF resins. XRD characterization indicated that NaMMT only intercalated when mixed with GLUF resin. Based on DSC results, the addition of NaMMT could accelerate the curing of GLUF resins. The enthalpy of the cure reaction (ΔH) of GLUF resin containing NaMMT was increased compared with neat GLUF resin. Also the results of FTIR analysis indicated that addition of NaMMT change the GLUF resins structures.     

Thermal,mechanical, and acoustic properties of silica‐aerogel/UPVC composites

The properties of silica‐aerogel/UPVC composites have been investigated with emphasis on sound and heat insulation. UPVC is a material of construction for window profiles and drainage pipes. Hydrophobic silica aerogels were synthesized using silicate sodium as a precursor through a two‐step sol–gel process. The physical and textural properties of the synthesized silica aerogels such as density, surface area, and particle size were analyzed using SEM and BET analysis. Then, the synthesized aerogels were mixed with Unplastisized Polyvinyl Chloride (UPVC) compound at five different weight ratios in an internal mixer to find out the effects of silica aerogels on the thermal, mechanical, and acoustical characteristics. The prepared UPVC/aerogel composites were characterized for tensile properties, impact strength, hardness, Vicat softening temperature, thermal conductivity, sound absorption, and sound transmission loss. The results revealed that adding silica aerogel in to the matrix of UPVC increases its hardness and softening temperature while decreases impact strength. The thermal conductivity of UPVC was decreased by up to 50% using silica aerogel. The sound absorption property of UPVC was increased up to three times by using silica aerogels due to its high porosity. Silica aerogel increased the maximum sound transmission loss of UPVC in the low frequency range. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44685.