Micro hole is the fundamental feature found in any device and its components. Hence this paper aims to produce the micro holes using electrochemical micromachining (EMM). The existing machining techniques in EMM for creating micro holes are associated with more overcut (OC). Hence, reducing OC and enhancing the machining rate (MR) is essential. This paper aspires to investigate the effect of the graphite electrode with magnetic force on the copper plate. Four different tools, namely the electromagnetic graphite tool (EMGT), permanent magnet graphite tool (PMGT), graphite tool, and stainless steel (SS) tool, are employed for these experiments. The major influencing factors are machining voltage in volts, duty cycle in % and electrolyte concentration in g/l was considered on MR and OC. The results revealed that EMGT, PMGT, and graphite electrodes produce MR of 106.4%, 74.6 % and 44.5 % over the SS tool at a parameter level of 23 g/l, 15 V, and 85%, respectively. Furthermore, graphite and EMGT electrodes resulted in 11.9% and 3.41% reduced OC, respectively, than the SS tool at parameter levels of 8 V, 95% and 28 g/l. Additionally, the scanning electron microscope (SEM) picture examination is conducted to identify the magnetic field effect on the work surface.

Honey is a product of high nutritional value, used as a raw material for obtaining mead. However, adding fruit juices, including chokeberry juice, can improve mead quality. This paper aims to assess the effects that adding different quantities of chokeberry juice, with the variation of 3 amounts of inoculated yeast, has on the fermentation and physicochemical, antioxidant, and antimicrobial properties of mead. The parameters analyzed are the dry matter content, pH value, and content of volatile acids, ethanol and methanol, total phenols and flavonoids, FRAP, DPPH, and ABTS tests, and antimicrobial properties. The results obtained in this paper show that adding chokeberry juice improves the antioxidant properties of the final product and positively affects the course of mead fermentation, i.e., it has led to an increase in the maximum concentration of ethanol. Regarding the chemical composition of mead, there is no significant difference, except in the obtained ethanol content, which is the highest in samples with 10% of added chokeberry juice. Furthermore, the control sample showed the best antimicrobial activity, while the sample with 5% added chokeberry juice showed the weakest effect. Finally, the strongest effect was seen in the sample with 20% of added chokeberry juice.

The challenging task in our ecosystem is to reduce acidic gas emissions to some extent. Many gases are emitted from the industries like H2S, CO, CO2, SO2, NO, and NO2 as exhaust gases. Among these gases, CO2, NO2, and SO2 are acidic, which results in adverse effects on humans, animals, and plants. The increase in the emission of CO2 gases from both anthropogenic and industrial sources resulted in CO2 mitigation studies. CO2 absorption studies were carried out using iron oxide nanofluid with the novel structured packed absorption column. Iron oxide nanoparticles were synthesized and characterized using XRD, SEM, and TEM analysis. Ammonia is used as an absorbent along with iron oxide nanofluid of three different concentrations (0.0001 w/v%, 0.001 w/v%, and 0.0015 w/v%). It was found that the iron oxide nanofluid of 0.0015 w/v% showed an improved % CO2 removal efficiency. This enhanced % CO2 removal efficiency was due to the increased interfacial area of the ameliorated contact between the liquid and gas phases. In addition, the magnetic field was introduced along with the packed column, which increased CO2 removal efficiency by 1.5%.

The study of drying kinetics and characteristics of agricultural products is essential for drying time estimation, designing dryers, and optimizing the drying process. Moisture diffusivity under different drying conditions is crucial to process and equipment design. The drying kinetics of paddy using a cabinet tray dryer was modeled using an Artificial Neural Network (ANN) technique. For predicting moisture ratio and drying rate, the Levenberg- Marquardt (LM) training algorithm with TANSIGMOID and TANSIGMOID hidden layer activation function provided superior results. A comparative evaluation of the predicting abilities of ANN and 12 different mathematical drying models was also carried out. The Midilli model was adequate for fitting the experimental data with an R2 comparable to that of the ANN. However, the RMSE observed for ANN (0.0360) was significantly lower than that of the Midilli model (0.1673 to 0.712). Effective moisture diffusivity increased with an increase in temperature from 15.05 10-9 m2/s to 28.5 10-9 m2/s. The activation energy for drying paddy grains varied between 6.8 kJ/mol to 7.3 kJ/mol, which showed a moderate energy requirement for moisture diffusion.

The potential of biogas production using fish waste (FW) and its effect on greenhouse gas (GHG) reduction and on energy production were evaluated on this research. FW was co-digested with anaerobic sewage sludge (SS). The FW was collected in the city of Bragan?a, northern Brazil, in which the fish industry is the main activity with a FW production of approximately 9,000 kg?day-1. The experimental part included five SS/FW ratios, and in two experiments hydrogen was added. The experiments were carried out for 30 days and the effect on the cumulative biogas and methane yields were analyzed. The GHG reduction was estimated using the amount of FW not discarded in the Bragan?a open dump; and the electricity generation was calculated using the methane yield. Besides, two kinetic models were performed. The results presented a GHG reduction of 1,619 tons of CO2e and an electricity production of 372 to 956 MWh?year-1. The analysis of variance indicated that the methane production was highly dependent on the SS/FW ratios which ranged from 76 to 138 mL?gvs-1. Finally, this research showed the benefit of using FW to generate biogas and electricity while reducing GHG emissions in a city where there is no energy project.

Variable speed drives are the most promising technique for reducing electric motors' energy consumption. This paper discusses energy savings by installing variable speed drives to control rotating equipment motors such as pumps, compressors, blowers, and fans in oil processing facilities. In addition to energy savings, variable speed drives will improve overall equipment efficiency, increase reliability, and reduce greenhouse gas (GHG) emissions. An energy audit was performed on a case study to investigate energy consumption for all electric motors. Technical and operational constraints for installing and operating variable speed drives were discussed. Installation requires adjustments in operation schedules and parameters to allow reducing energy consumption. The case study has illustrated how to calculate energy savings for pipelines, air coolers, air blowers for furnaces, pumps with variable flow rates, and reciprocating compressing systems. Variable speed drives were technically and economically accepted in air blowers, fans, and pumps. Energy consumption and GHG emission were reduced by 67%. The payback period for the whole project was less than one year. Meanwhile, it was not valid for reciprocating compressors as the payback period was 6.2 years.

Nowadays, various industrial and urban activities result in discharging enormous quantities of various pollutants and their accumulation in the environment. Considering that heavy metals in wastewater are a serious threat to the environment and human health and that conventional methods for their removal are not highly efficient, the current study mainly focuses on estimating cyanobacterial capability to accumulate different heavy metals from water and comparing bioaccumulation and biosorption processes. Cyanobacteria Nostoc sp. was used, and five heavy metals were selected for this experiment (Cd2+, Cu2+, Pb2+, Ni2+, Zn2+). Examined concentrations of HMs were 20 mg/dm3, 80 mg/dm3, and 200 mg/dm3 for the bioaccumulation study, while 20 mg/dm3 and 80 mg/dm3 of each HMs were used for biosorption experiments. Living cells of Nostoc sp. have the highest affinity for Pb2+ (98.15%) and Cu2+ (95.14%) removal from the solution by bioaccumulation. During the biosorption process, dried biomass of Nostoc sp., besides Pb2+ (92.27%) and Cu2+ (96.00%), shows a high affinity for Cd2+ (91.00%) removal. Living cyanobacterial cells of Nostoc sp. could accumulate 82% of Zn, while dried biomass adsorbs 87% of Zn2+. Although the highest bioaccumulation of Ni2+ was only 38% while using the biosorption process, it was significantly higher (63.80%). These results could provide a preliminary study for further investigation in the direction of the development of immobilized biosorbents which could be used for industrial effluent treatment.

This study aims to examine the operating pressure effect on the manufacture of biodiesel from Palm Kernel Fatty Acid Distillate (PKFAD) by using para-Toluene Sulfonic Acid (PTSA) catalyst. The operating pressures studied are the vacuum pressures of 70 kPa, 80 kPa, 90 kPa, and 100 kPa, which varied with PTSA concentrations of 5%, 10%, 15%, 20%, 25%, and the molar ratios of methanol and PKFAD are 5:1, 6:1, 7:1, 8:1, 9:1, 10:1. Biodiesel production from PKFAD is carried out with reaction duration of 120 minutes and reaction temperature at 50 0C. The amounts of fatty acids converted to biodiesel are calculated based on the initial acid number and the acid number after the esterification reaction. The results obtained show that a vacuum pressure of 70 kPa to 100 kPa provides a conversion above 96% for all catalyst concentrations and all molar ratios of methanol and PKFAD. The highest conversion of PKFAD to biodiesel of 98.6% is obtained at an operating pressure of 80 kPa, a catalyst concentration of 25%, and the molar ratio of methanol and PKFAD is 10:1. The biodiesel characteristics obtained in this study have met the standards of the American Society for Testing Materials.

The catalytic production of diphenylmethane from the reaction of benzene with benzyl alcohol was investigated using HZSM-12 and desilicated HZSM-12 that was obtained by treating ZSM-12 with 0.2M NaOH solution at 85?C for 60 min. The untreated and alkaline treated ZSM-12 zeolites were characterized by X-ray diffraction, nitrogen adsorption/desorption isotherms, scanning electron microscopy, inductively coupled plasma optical emission spectrometry, and temperature-programmed desorption of ammonia. The desilicated HZSM-12 showed promising catalytic performance with benzyl alcohol conversion of 100 %, selectivity to diphenylmethane of 74 % (in 4 h reaction time), and that of 87 % (in 8 h reaction time). The reaction parameters affecting benzyl alcohol conversion and product distribution were also presented. The activities of fresh and regenerated catalysts were compared and characterization results indicated that the occluded organic molecules decreased the number of acidic sites of the catalyst after the reaction and regeneration.

One of the major environmental problems caused by stainless-steel industries is the liquid effluents generated during the production processes. It contains a high concentration of metal ions such as Fe (III), Cr (III), Cr (VI), and Ni (II) in HF and HNO3 mixture, oil, and rinse wastewater. The used pickling waste stream has a pH of 0.5, and Total Dissolved Salts (TDS) of 520g/L with a density of 1.20g/CC. The present work focused on the recycling of pickling effluent by applying a combination of filtration, resins, and neutralization for the efficient removal of metal ions and F- greater than 99.5%. Laboratory experiments were performed using micro and ultra-filters with a membrane area of 0.2m2 for the removal of TDS. Cr (VI) was removed using TulsionFSMP 6301 resin and desorption using NaNO3 and subsequent conversion into Na2Cr2O7 as a by-product. For neutralization, Ca(OH)2, NaOH were used to precipitate metal ions and the resulting filtrate was polished using ZrOCl2 for effective removal of F- to 0.12 mg/L. The nitrate was recovered as NaNO3. Adsorption isotherm and kinetic studies were utilised for Cr (VI) from experimental data and a process flow diagram is developed, which can eventually be tested on a larger scale.