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High-temperature operation, such as in gas turbine engines, is typically limited by the ability of materials to withstand extreme operating conditions. The need for a combination of high-temperature strength and oxidation resistance, as well as microstructural stability, has led to the continued use of nickel-based superalloys as materials for turbine blades, the most critical component in aero gas turbine engines. Due to their limited melting points, materials beyond superalloys are needed to meet increasing fuel efficiency requirements. High entropy alloys have recently been considered as candidates for materials to replace nickel-based superalloys. This paper discusses the microstructures and high-temperature oxidation behavior of Al0.75CoCrCuFeNi high entropy alloy at 900, 1000, and 1100°C. It was found that the oxidation rate constants for Al0.75CoCrCuFeNi oxidized at 900, 1000, and 1100°C are 3.84 x 10-10, 5.99 x 10-10, and 8.97 x 10-10 (mg/cm2.s), respectively, with an activation energy for oxidation of 66.58 kJ/mol.

A portable and low-cost system prototype for glucose detector based on LMP91000EV M potentiostat has been created. Characterization of Screen-Printed Carbon Electrodes (SPCE) without modification (bare SPCE) and modified nickel oxide (NiO/SPCE) was carried out with a commercial potentiostat to see the effect of nickel oxide in detecting glucose. Through the electrochemical impedance spectroscopy method, the Rct value of 1,276.79 Ω is obtained for NiO/SPCE and 429.06 Ω for bare SPCE, so that NiO/SPCE has a slower electron transfer rate. Meanwhile, through the cyclic voltammetry method, the surface-active electrode area is 7.1×10-2cm2 for NiO/SPCE and 6.9×10-2 cm2 for bare SPCE, so that NiO/SPCE is more sensitive in detecting glucose. When the glucose concentration is varied, the Limit of Detection (LOD) and Limit of Quantitation (LOQ) values of NiO/SPCE are smaller, specifically 1.807 mM and 6.024 mM than bare SPCE, specifically 2.629 mM and 8.762 mM, so NiO/SPCE is more sensitive. When the scan rate is varied, the gradient value of NiO/SPCE is smaller, specifically -8.14×10-4 mA s/mV than bare SPCE, specifically -9.62×10-4 mA s/mV, so NiO/SPCE is not more sensitive. Next, comparing a prototype system that Trans Impedance Amplifier (TIA) gain is varied and a commercial potentiostat. As a result, the cyclic voltammogram per cycle on commercial potentiostat is more stable. The smaller the TIA gain on the system prototype, the more stable it is, this is because the noise that is amplified is getting smaller.

The modification of the multi-walled carbon nanotube screen-printed electrode (MWCNT/SPE) with gold nanoparticles (AuNP) was achieved through drop-casting method utilizing gold nanoparticles synthesized via the Turkevich method. The combination of nanomaterial based on carbon (multi-walled carbon nanotubes) and the noble metal (gold nanoparticles) aims to exploit the synergistic benefits of the two materials in electrochemical measurement. Electrochemical performance was evaluated through techniques including cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The results indicated an increase in the electroactive surface area of the modified working electrodes compared to the unmodified ones. This increase in electroactive surface area can be attributed to the successful decoration of AuNP, which facilitates greater surface interactions and improved electron transfer kinetics, crucial for efficient catalytic reactions. The decoration of AuNP also makes sure that the electrode will have good biocompatibility for future bioanalytical applications. This investigation’s main goal was to determine the effects of the AuNP modification methods to the carbon electrode’s electroactive surface area for further contributing to the development of efficient label-free sensing platforms for diverse applications in biosensing.

HAp and Zr-doped HAp nanoparticles were synthesized from bovine bone and local zircon material by using the hydrothermal method. XRD analysis showed that the HAp and Zr-doped HAp nanoparticles had hexagonal structure with a crystallite size of 20-36 nm and the lattice constants a = 9.8-9.9Å and c = 6.5-6.8 Å. XRD data also showed that up to 20 at.% of Zr can be accommodated in HAp crystal structure. The lattice constant and cell volume decreased with increasing Zr concentration. FTIR data confirmed that the majority of functional groups that exist on the surface of the HAp and Zr-doped HAp nanoparticles were the hydroxyl and phosphate groups. Suspensions with the HAp and Zr-doped HAp nanoparticles prepared using citric acid as dispersant were stable with zeta potential between −31 and −35mV at pH = 7. Reactive oxygen species are generated on the produced HAp and Zr-doped Hap nanoparticles and confirm their potential for application in photodynamic therapy.

Aerodynamic performance of a horizontal axis wind turbine blade is affected by its span stacking whether it is two (2D) or three-dimension (3D). The optimization by including swept or/and dihedral at the blade tip tends to enhance its aerodynamic behavior. In order to correctly select the swept angle and anhedral in designing 3D blades, the behavior of the blade geometry variation should be characterized. By using wind tunnel experimentation, modified blades at their tips by swept and anhedral are characterized. Swept tip blade modification only produces weak torque generation while adding anhedral tip blade modification enhances the produced torque significantly. Keywords: Small HAWT, Blade tip shape, Tip loss, Roll-up vortex, Performance

Petrozon Rossy-22 is one of hydrocarbon refrigerants which environmentally safe, since there is no effect on either ozone depletion or global warming. In the refrigeration cycle, imperfect vacuuming process or other factors that permit circulation of air taken place in the system predicted influencing heat transfer rate in condenser. Therefore, research on the influence of air fraction against condensation heat transfer coefficient of Petrozon Rossy-22 inside vertical pipe to be done. A modified refrigeration system of vapor compression was applied in this research, where the condensation was done in the 2 meters straight vertical condenser (double pipe heat exchanger, that further called as test section). The diameter of internal and external pipe were ¾” and 1 ¼” respectively. Electric heater was installed on upstream of the test section. Mixture of air- refrigerant was flowed downward inside internal pipe, while cooling water was flowed upward through annulus. The varied parameters were: air fraction, air-refrigerant and cooling water flow rate. The result of the research indicated that condensation heat transfer coefficient significantly decreased when air fraction increased. The proposed empiric equation is : Nu = 0.0138. (1-w)8.8198. Re0.7941. Pr4.7315with determination coefficient of 0.6927 and average absolute deviation of 17.65 %. The equation was for Re= 6.922-12.953, Pr= 2,008-2,696, and w= (0,25-1)%.

ABSTRAK Pemanfaatan energi air di Indonesia, khususnya untuk pembangkit listrik skala kecil di pedesaan masih perlu diprioritaskan untuk ditingkatkan dalam program memperoleh energi bersih yang ramah lingkungan. Pemanfaatan tersebut masih terkendala oleh biaya investasi yang relatif tinggi serta teknologi yang sesuai. Pemerintah mendorong pemanfaatan energi baru dan terbarukan melalui program Desa Mandiri Energi dengan menggunakan potensi dan sumber daya yang tersedia di pedesaan. Kajian ini bertujuan untuk mengevaluasi unjuk kerja turbin air Pelton untuk pembangkit listrik skala kecil dengan sudu terbuat dari bambu dan roda turbin dari kayu. Data yang terkumpul menunjukkan bahwa efisiensi pembangkitan mampu mencapai sekitar 28% untuk debit aliran 28 liter/detik dan tinggi jatuh efektif 7 m menggunakan nosel berpenampang empat persegi panjang. Walaupun dari aspek teknik dan lingkungan penggunaan bambu sebagai sudu turbin adalah baik dan sesuai untuk digunakan di pedesaan, namun unjuk kerja yang diperoleh masih perlu ditingkatkan dibanding dengan umumnya turbin Pelton yang terbuat dari logam. Hal ini diperkirakan karena bentuk alamiah lengkung bambu yang tidak optimum untuk sudu serta bentuk penampang nosel yang masih harus disesuaikan. ABSTRACT The use of hydroenergy in Indonesia, especially for small electric generation in rural areas is still to be priority increased in a program to find a clean and environmentally friendly energy. The use is still limited by relatively high investation cost and appropriate technology. Government has pushed the use of new and renewable energy through the Village Self-Relliant Energy Supply Program by using potential and available resources in the village. The objective of this study is to evaluate the performance of a hydraulic Pelton turbine for small electric generation with the buckets are made of bamboo and the runner is made of wood. Data collected from the study show that the efficiency of the generation is capable to be in about 28% for the flow rate of 28 liter/s and effective head of 7 m by using nozel which has a rectangular cross section. Although the use of bamboo as turbine buckets is technicality and environmentally good and it is suitable to be operated in villages but the performance achievement is still need to be increased compared to that of usual Pelton turbine wich is made of metal. This was predicted due to the natural curve profile of the bamboo which is not optimal fit for buckets and the cross sectional geometry of the nozel is still need to be fitted.

Biofuel is one of alternative energy that is being developed today to solve the problem of limited fossil fuel as an energy source. The goal of this study is to produce biofuel from kapuk (Ceiba pentandra) seed oil (KSO) through catalytic hydrocracking process using NiMo/HZSM-5 catalyst. NiMo/HZSM-5 catalyst was obtained by impregnation of nickel and molybdenum as metallic precursors on HZSM-5 catalyst as support using incipient wetness impregnation method. It was found that the surface area of the catalyst was 222.1350 m2/g, the pore diameter was 3.0148 nm and the pore volume was 0.1674 cm3/g. The diffraction peaks of nickel oxide phase and the metallic phase of nickel were observed at 2θ of 62.5102° and 51.7283°. Molybdenum oxide phases were observed at 2θ of 53.5674° and 60.4682°. The catalytic hydrocracking process was performed using slurry pressure batch reactor at the temperature of 350°C for 2 h. The obtained liquid product was analyzed using GC-MS in order to determine the organic content. It has been found that the highest compounds were the palmitic acid with 23.14 area%. Besides, the hydrocarbon composition consisted of 33.93 area% (i.e. 4.34 area% cycloparaffins, 16.02 area% n-paraffins, 12.26 area% olefins, and 1.30 area% of aromatics) and 58.73 area% of carboxylic acid. Thus, it can be concluded that NiMo/HZSM-5 catalyst can convert KSO into biofuel through catalytic hydrocracking process at the temperature of 350°C for 2 h.

With an intention to reduce the consumption of energy from fossil fuels and the CO2 emission in relation with the climate change solution, Indonesian Government has targeted that the role of the New and Renewable Energy (NRE) resources reaches at least 23% , or about 27 GW , in 2025 and it is expected to increase to the extent of about 134 GW in 2050 within the scenario of mixed energy supply. Geographically Indonesia has many remote and isolated areas with lack of appropriate infrastructure supports. But in the most of the areas, huge potential of new and renewable energy are available such as hydro energy is about 75 GW, biomass energy is about 32 GW and bio fuel is about 32 GW. The total utilization of the energy from small hydro energy up to this year for example is only about 300 MW. The significant obstacle in optimizing the utilization of small hydro energy in the areas is mainly on the infrastructure conditions and the local manufacture capabilities. Difficulties in mobilization of experts, skill worker , parts and constructions material result in very time consuming and costly for site construction. In this research a hydro turbine built in knock down container completed with a Francis turbine in cylindrical form housing is proposed and reported its performance on implementation. The hydro in a knock down container concept comes from the idea to manufacture hydro power solutions in a knock down container, readymade to be transported to installation sites. It can be easily manufactured in a quality controlled and cost effective environment, transported and installed in remote areas, to operate and maintain with minimal amount of equipment. It shows that the implementation of the unit in a remote area has reduced the total site construction time by 1/3 compared to the predicted one with conventional unit. The performance of the Francis turbine with cylindrical form housing has shown comparable with the conventional one which has volute form housing. The superiority was even more pronounced by introducing a deflection insert in its input flow channel. The insertion was capable to create more distributed flow into the runner. Efficiency of the turbine up to 80% was performed in this research. Local manufacture for turbine usually use many craft work and welding to built a volute form housing for the Francis turbine. The cylindrical form housing here has also proven significantly in reducing the time and price for the turbine manufacturing process.

Refractory high-entropy alloys (RHEA) are considered as potential candidates for new-generation energy-related high-temperature applications. However, the poor high-temperature oxidation resistance of RHEAs, resulting in phenomena such as significant weight gain, scale spallation, pesting, and even complete oxidation, limits their applications. In this study, the oxidation behavior of AlxHfNbTiVY0.05 (x = 0.75; 1; 1.25) high-entropy alloys was investigated at 700–900 °C. The isothermal oxidation tests showed that the oxidation resistance of AlxHfNbTiVY0.05 RHEA is strongly influenced by temperature and time. In addition, accelerated oxidation, known as pesting, was observed to occur at 700 °C for all alloys; while, partial spallation was observed at 800 °C for the Al1 and Al1.25 alloys. Detailed analyses of oxidation kinetics have been carried out for the oxidation test series at 900 °C. The mechanism behind disintegration was investigated and attributed to accelerated internal oxidation followed by the formation of voluminous Nb2O5, TiNb2O7, and fast-growing AlNbO4, and is also thought to be related to the partial evaporation of V2O5. [ABSTRACT FROM AUTHOR]

The primary objective of this study was to explore the potential of Murraya koenigii as a natural alternative to synthetic antimicrobial agents for the treatment of edwardsiellosis in gourami fish (Osphronemus goramy). This research employed a combination of both experimental and descriptive methods. The research followed a two-stage approach. In the first stage, antibacterial compounds were extracted and characterized from M. koenigii leaves, followed by an assessment of their antibacterial activity against Edwardsiella tarda. The second stage involved applying the crude extract of M. koenigii, known for its antibacterial properties, to gourami fish infected with E. tarda. The findings revealed that M. koenigii predominantly contains alkaloids, terpenoids, saponins, flavonoids, and tannins, all of which exhibit antibacterial activity. The application of the crude M. koenigii extract had a substantial impact on the hematological profile of the infected gourami fish. The most effective dose in treating Edwardsiellosis in gourami fish was found to be 600 mg/L, as it significantly improved various hematological parameters, including hematocrit, hemoglobin, erythrocyte count, leukocyte count, lymphocytes, monocytes, and neutrophils. Additionally, histopathological analysis showed improvements in tissue conditions, with lower scores for degeneration, congestion, and necrosis. Furthermore, the survival rate of gourami fish reached its highest at 83.33% when treated with the 600 mg/L dose of M. koenigii extract. These results suggest the potential of M. koenigii as an effective alternative for the treatment of Edwardsiellosis in gourami fish. However, further research is needed to assess the practical application of M. koenigii extract in gourami fish culture. [ABSTRACT FROM AUTHOR]

Introduction: Diabetes mellitus has been perceived as the worsening factor for coronavirus disease 2019 (COVID-19), where diabetes mellitus patients with pre-existing inflammatory condition could develop acute respiratory disease syndrome as well as multi-organ dysfunction. Managing diabetes mellitus amidst severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is also a matter of concern as several antidiabetic therapies could affect the progression of COVID-19. This study aimed to provide the clinical characteristics and outcomes of patients with both COVID-19 and diabetes mellitus receiving blood glucose lowering therapies and COVID-19 symptomatic treatments. Methods: This retrospective study was performed on 260 medical records of patients hospitalized between May 2020 to February 2021 in East Java, Indonesia. Patients were confirmed COVID-19 positive based on the results from real time polymerase chain reaction (RT-PCR) using nasal swab samples collected on hospital admission. Data included were demographic characteristics, COVID-19 symptoms, severity of COVID-19, comorbidities (other than diabetes mellitus), fasting blood glucose (FBG), and 2-hours post-prandial blood glucose (2hPBG), and outcomes. Results: Most of the patients had age range of 41–60 years old (76.1%) with more than a half of the subjects (60%) were obese. Patients with uncontrolled diabetes were distributed evenly among the COVID-19 severities (74.3% in asymptomatic group, 73.6% in mild group, and 74.1% in moderate group). There were reductions in FBG and 2hPBG levels measured before (210.75±81.38 and 271.19±100.7 mg/dL, respectively) and after the treatment (181.03±68.9 and 222.01±86.96 mg/dL, respectively). All patients received multivitamin and symptomatic treatment for COVID-19. Oral antidiabetic drug (57.6%) and insulin (28.8%) were administered to lower the blood glucose level of the patients. As many as 96.9% patients survived, while 3.1% died. Conclusion: COVID-19 could affect the blood glucose level, suggesting the importance of antihyperglycemic therapies among patients with both COVID-19 and diabetes mellitus.

In this study, several types of zirconium-based alloys supplemented with 2, 3, and 4, in wt.% of yttrium for corrosion resistance enhancement were investigated. The specimens were prepared by a single arc welding furnace in an argon-controlled atmosphere. By optical and scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and electrochemical tests, the effect of different portions of yttrium on the surface morphology, phase structure, and corrosion resistance in the Zr alloys were analyzed. As of result of arc welding, the specimens were obtained and examined by optical microscope and then homogenous structures were observed. These structures are matrix (Zr-rich) and oxides. Furthermore, as of the characterization results by X-ray diffraction, the main compound of the alloys was Zr6Mo6AlTi, while others were AlZr3, MoO2, ZrO2, and Y2O3 oxides. Yttrium addition in the alloys prior to the corrosion test led to thickened grain boundaries but reduced grain size. The Y2O3 itself remained at the grain boundaries as clusters. The corrosion test was performed in Ringer's lactate solution by using anodic polarization. The effect of yttrium addition into Zr-based alloys was found to be beneficial by shifting the corrosion potential toward a positive value. Zr-6Mo-6Al-Ti-4Y had a higher open corrosion potential value than the other two alloys. The difference was approximately 200 mV. However, the passive region of Zr-6Mo-6Al-Ti-4Y was the shortest and broke down at an earlier stage. The formation of these kinds of oxides was the reason for the increase in corrosion potential of Zr-based alloys with 4% Y added. [ABSTRACT FROM AUTHOR]

Gynecomastia is an enlargement of breasts in men. This disease is commonly found in patients with impaired liver function and patients on additional hormonal use. Approximately, 10% to 25% of gynecomastia instances are attributed to the use of pharmaceutical substances. This study presented the case of a 41-year-old male patient with complaints of breast enlargement for 2.5 years before the examination. Breast enlargement was felt slowly without any period of shrinking, and no complaints of breast pain hardening, or nipple discharge. The patient was diagnosed with Auto Immune Deficiency Syndrome (AIDS) in 2009 and taking a Fixed-Dose Combination (FDC) of Anti-Retroviral Therapy (ART) with the composition of tenofovir, lamivudine, and efavirenz once a day. History of hormonal uses, other drugs, and alcohol consumption was denied. According to the physical examination, the patient had an adequate nutritional status, a BMI of 20.8 kg/m2, and enlargement of right and left breasts, the left breast was larger. According to the palpation, the enlarged breasts were firm and supple and there was no erosion or nipple discharge, or breast pain. The laboratory examination showed hepatitis marker, hormonal and thyroid levels are within normal limits. Medications are estimated to account for 10-25% of gynecomastia cases. Efavirenz decreases androgen activity through unknown factors. Several assumed mechanisms include the direct mammotropic effect of ARTs, and elevated IL-2 and IL-6 production due to T-helper cytokine response, thereby increasing the estrogen production which stimulates breast growth. Surgery can be done for cosmetic purposes. [ABSTRACT FROM AUTHOR]