Effects of Galvanic Interaction between Chalcopyrite and Monoclinic Pyrrhotite on Their Flotation Separation

The galvanic interaction between chalcopyrite and monoclinic pyrrhotite and its effect on flotation separation were studied using monomineral flotation tests, adsorption capacity tests, X-ray photoelectron spectroscopy (XPS) characterization, and scanning electron microscopy (SEM) test. These results showed that the interaction promoted the reduction of O2 on the cathodic chalcopyrite surface and accelerated the generation of Fe(OH)3, which was not conducive to collector adsorption; hence, the flotation recovery decreased by 10–16%. On the other hand, galvanic interaction accelerated the oxidation of S on the anodic monoclinic pyrrhotite surface to S0 or SO42− and produced a large amount of H+, thus preventing the formation of Fe(OH)3. Meanwhile, the Cu2+ eluted from chalcopyrite surface activated monoclinic pyrrhotite; hence, the flotation recovery increased by 3–10%. Galvanic interaction reduced the floatability difference between the two minerals, and the separation difficulty was significantly increased. Even with an increase in the amount of lime, the separation could not be improved.

Karakteristik Membran Komposit Polietersulfon, Polivinilpirolidon dan Kitosan

Polyethersulfone (PES) is a membrane forming material that has many advantages but is hydrophobic, so it is necessary to add other materials, such as composite PES with Polyvinylpyrrolidone (PVP) and chitosan. The addition of PVP aims to change the nature of the PES membrane to be hydrophilic and the addition of chitosan aims to improve the mechanical properties of the polymer. The purpose of this study was to study the effect of adding PVP and chitosan to the characteristics of PES membranes. The membranes were made using a phase inversion technique by immersion precipitation with a concentration of 20% PES, 1% PVP, and chitosan were varied, namely 0% (M0 membrane), 1.5% (M1), 2% (M2), and 3% (M3). The results of the permeability test showed that the membranes M0, M1, M2, and M3 are classified as nanofiltration membranes with Lp values of 9.1237, 7.618, 6.9651, and 4.4077 L/m2.h.bar. The swelling degree value is 61,512; 103.111; 145,564; and 158.610% and the overall porosity value is 22.892; 32.360; 80.726; and 117.016%. The SEM test showed that the morphology of the membrane changed its structure as the concentration of chitosan increased. The FTIR test on the membrane showed that there were absorption bands, each of which identified its functional group.

Molecular Expressions : Scanning Electron Microscope (SEM) in Gills of Cyprinus carpio Infected Myxobolus sp.

Highlight Research:It has been found that many fish died with wounds from farmers in Blitar, Indonesia.The mucosal smear test from mucosal gills of C. carpio infected with Myxobolus.In the blood smear test of C. carpio, there was no myxobolus found in the blood.In gill organ testing using SEM that Myxobolus is found in gills (C. carpio).The shape of Myxobolus resembles an imperfect ball with a hollow in the middle. AbstractThe biggest problem that is often considered to be an obstacle to Common carp culture is the emergence of disease attacks. One type of disease that often attacks the seeds of Cyprinus carpio is Myxobolus (a systemic parasite that can cause harm to fish farming). The aim of this study was to determine the molecular expression through the smear test on C. carpio gills, to determine the image of the gill organs of C. carpio using the SEM test, and to determine the description of the spores of Myxobolus sp. Data were analyzed using descriptive methods. Descriptive method used was comparative descriptive comparing molecular expression in the test of gill mucosal smear of fish using a light microscope and gill organ testing using Scanning Electron Microscope (SEM) on C. carpio infected by Myxobolus sp. In this study, the results showed that in C. carpio infected with true Myxobolus found the presence of Myxobolus in the mucosal smear test and SEM test on gill tissue, but not found in the blood smear test.

Research on Dewatering Ability of Municipal Sludge under the Treatment of Coupled Acid and Microwave

Municipal sludge is a by-product of urban sewage treatment; it has high water content and contains many hydrophilic extracellular polymeric substances (EPS). It is difficult to achieve deep dewatering of sludge. Therefore, it is necessary to find an efficient method to treat sludge. In this study, an acid-microwave treatment method was proposed to improve the dewatering ability of sludge. A vacuum filtration test and particle size analysis test were used to explore the improvement effect of dehydration performance. After centrifugation, the concentrations of soluble proteins and polysaccharides in the supernatant were measured to explore the disintegration of acid-microwave treatment on EPS. Finally, the microstructure of sludge treated by acid-microwave was studied via the SEM test. The results showed that short-term microwave radiation was conducive to sludge dewatering. However, the sludge dewatering performance deteriorated significantly when the treatment time was too long. The optimal microwave treatment condition was 700 W for 180 s, and the SRF of sludge was the lowest, which was 10.11 × 10 12 m / kg . After acid-microwave treatment, sludge particle size increased significantly. The concentration of protein and polysaccharide in supernatant increased with the increase of microwave treatment time. Acid-microwave treatment could significantly improve the release efficiency of the polysaccharide. Through the SEM test, it can be verified that the bulk floc structure of sludge is broken after microwave treatment, and acid-microwave treatment is beneficial to the aggregation of floc fragments to form large particles, which can provide larger pores for drainage.

Wear Characteristics Optimization of Al6061-Sugarcane Bagasse Ash Metal Matrix Composite Using Taguchi Method

In present work, Aluminium 6061 was reinforced by varying the percentage of sugarcanebagasse ash (SCBA). Al-SCBA composite samples were fabricated by stir casting method. The weartest conducted on the samples using a pin on disc machine under the normal sliding condition. Basedon the testing parameters (Volume fraction ‘V’, Load ‘L’, sliding speed ‘S’) an L27 Orthogonal arraydesign was selected. According to L27 array, the wear & friction test was conducted. variance analysis(ANOVA) was performed to find out the important parameter and contribution in percentage for eachparameter on the composite material. To verify the analysis results with experimented resultconfirmation test was carried out. Further, to find the wear mechanism on the composite sampleselectron microscopy (SEM) test was used.

Experimental Investigation on the Effect of Rubber Powder on Mechanical Properties of PVA Fiber Concrete

To verify the damping improvement by replacing partial sand with rubber powder in the concrete process, this study investigated the effects of the rubber powder (5%, 10%, 15%, and 20%) on the mechanical properties and micromechanism of polyvinyl alcohol (PVA) fiber-reinforced concrete. In addition, in order to discuss its damping performance, free vibration test was conducted. Microstructure analyses were conducted by the scanning electron microscope (SEM) test. These results indicated that, as the content of the rubber powder increased, the damping ratio increased, and the compressive strength decreased, but this strength loss can be effectively controlled by adding PVA fiber. The rubber powder with a volume content of 5% and PVA with a mass of 2.4 kg/m3 were the most optimal mixing to balance the strength and damping requirement. According to the SEM test results, the rubber powder was beneficial to improve the damping ratio of PVA concrete, but it aggravated its interface defects.

PENGARUH INTERAKSI GENOTIP DAN LINGKUNGAN TERHADAP PENINGKATAN PRODUKTIVITAS TANAMAN BAWANG MERAH MENGGUNAKAN METODE SEM-AMMI

Stable and adaptive superior varieties play an important role in increasing plant productivity. The technological innovation was carried out by studying the yield GEI. However, if only paying attention to yield GEI would not be enough in selecting stable and adaptive varieties, so this research used a combination of AMMI and SEM methods. Through the SEM-AMMI, GEI modeling was carried out by taking into account the physiological processes of growth and genotype development which explained the relationship between yield GEI components and how it affected yield GEI. The results of the AMMI biplot showed that genotypes were adaptable and relatively stable were planted in five planting locations, namely Biru Lancor and Tinombo. SEM test results showed that the yield component has an effect on production yield, where the tuber weight above the average will give relatively more onion yields and genotypes planted in relatively low locations, soil pH above 6 and dusty clay soil conditions will produce relatively more red onions and quality.

Effects of MgO Nanoparticles on Thermo-Physical Properties of LiNO3-NaNO3-KNO3 for Thermal Energy Storage

Molten salt LiNO3-NaNO3-KNO3 has been investigated as heat transfer and thermal storage media for its low melting point and good thermal performance. In this paper, nanofluids were synthesized by dispersing MgO nanoparticles into LiNO3-NaNO3-KNO3, and the effects of nanoparticles on thermal properties were studied with different sizes (20–100 nm) and mass percent concentrations (0.5–2.0 wt.%). The addition of nanoparticles had little effect on melting temperature, and led to a slight increase in enthalpy of fusion by 2.0–5.5%. Compared with base salt, the density of nanofluid increased a little by 0.22–1.15%. The scanning electron microscope (SEM) test implied that nubby and punctate microstructures were responsible for larger surface area and interfacial energy, which could lead to the improvement of specific heat capacity reaching 2.6–10.6%. The heat transfer characteristics remarkably increased with the addition of nanoparticles, and the enhancement of average thermal diffusivity and conductivity of salt with 1 wt.% nano-MgO could be 5.3–11.7% and 11.3–21.2%, respectively. Besides, the viscosities of nanofluids slightly increased for 3.3–8.1%. As a conclusion, nano-MgO was positively influential on the thermal properties of LiNO3-NaNO3-KNO3 base salt.

Kepuasan kerja sebagai variabel mediasi pada pengaruh stres kerja terhadap niat keluar

This research is motivated by the high turnover among Y and Z generation caused by the level of. work stress caused by workload and unclear work procedures. This study aimed to determine job satisfaction as a mediator of the relationship between work stress and turnover intention. This study used quantitative methods with full sampling and respondents as many as 65 employees. The data analysis technique was performed using SEM test with WarpPLS 7.0 software. Based on the test, results showed that work stress has a significant effect on turnover intention and job satisfaction is evident to be intervening variable.

Morphology and thermal properties of polypropylene-montmorillonite nanocomposite using modified bentonite of Bener Meriah Aceh

Research on the use of modified bentonite from Bener Meriah Aceh to study the morphology and thermal properties of polypropylene-montmorillonite nanocomposite (PP-MMT) was carried out. Bentonite was isolated into nano-sized montmorillonite and modified with the addition of PP-g-MA as a compatibilizer and octadecylamine as a modifier of MMT. PP-MMT nanocomposite processing was carried out in an internal mixer at 180 oC with a time of 10 minutes, and a speed of 65 rpm. Based on the results of the TGA-DTA test, the modified bentonite from Bener Meriah Aceh with PP-g-MA and octadecylamine can improve the thermal properties of PP-MMT nanocomposite in a composition comparison of PP; PP-g-MA; MMT is 85; 10; 5. The SEM test results also showed that exfoliation and intercalation had occurred of MMT at PP-MMT nanocomposite.