Jurnal Fisika Unand
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Sintesis Nanopartikel ZnO Menggunakan Prekursor ZnCl2 dan Polimer Penstabil Tween 80 untuk Aplikasi Tabir Surya
Full text linkZnO nanoparticles are semiconductor materials with a wide energy band gap (3.37 eV), making them excellent for use as sunscreen ingredients due to their superior ultraviolet protection properties. ZnO nanoparticles are superior to other conventional sunscreen materials because they do not cause skin irritation or allergies. The purpose of this study was to synthesize ZnO nanoparticles as a sunscreen material using Tween 80 stabilizing polymer and to comprehensively examine the effect of Tween 80 concentration on the characteristics of the resulting ZnO nanoparticle sunscreen. ZnO nanoparticles were synthesized using ZnCl2 and Tween 80 precursors with a Rotor Stator Homogenizer equipment system. Four different concentrations of Tween 80 were used to observe their effect on the characteristics of the resulting ZnO nanoparticles. The results showed that the average diameter of ZnO nanoparticles, their polydispersity index, and their zeta potential decreased as the concentration of Tween 80 used increased. Their optical transmittance was very high in the visible light spectrum and very low in the ultraviolet spectrum, especially for ZnO nanoparticles with the smallest average diameter (11.6 nm). This means that the visible light transmission and ultraviolet light absorption are excellent. In addition, the absorption edge is also very sharp. These three properties indicate that the ZnO nanoparticles produced are very suitable and have great potential for use as a sunscreen material.Nanopartikel ZnO adalah material semikonduktor dengan celah pita energi yang lebar (3,37 eV) sehingga sangat baik dijadikan sebagai bahan tabir surya karena unggul sebagai agen pelindung ultraviolet. Nanopartikel ZnO lebih unggul dibanding dengan bahan tabir surya konvensional yang lain karena tidak menyebabkan iritasi atau alergi pada kulit. Tujuan penelitian ini adalah mensintesis nanopartikel ZnO sebagai bahan tabir surya dengan menggunakan polimer penstabil tween 80, dan mengkaji secara komprehensif pengaruh konsentrasi tween 80 terhadap karakteristik tabir surya nanopartikel ZnO yang dihasilkan. Nanopartikel ZnO disintesis menggunakan prekursor ZnCl2 dan tween 80 dengan sistim peralatan Rotor Stator Homogenizer. Empat ragam konsentrasi tween 80 digunakan untuk melihat pengaruhnya terhadap karakteristik nanopartikel ZnO yang dihasilkan. Dari hasil yang diperoleh menunjukkan, diameter rata-rata nanopartikel ZnO, indeks polidispersitasnya, dan potensial zetanya mengecil ketika konsentrasi tween 80 yang digunakan, diperbesar. Transmitans optiknya sangat tinggi di daerah spektrum sinar tampak dan sangat rendah di daerah spektrum sinar ultraviolet terutama untuk nanopartikel ZnO yang memiliki diameter rata-rata yang terkecil (11,6 nm). Artinya, transmisi sinar tampak dan serapan sinar ultravioletnya sangat baik. Selain itu, absorption edge-nya juga sangat tajam. Dari ketiga sifat ini menunjukkan bahwa nanopartikel ZnO yang dihasilkan ini sangat cocok dan potensial untuk digunakan sebagai bahan tabir surya.
 
Datos TOMATE y CALABACÍN proyecto Optimización del fertirriego en cultivos hidropónicos con mezcla de agua desalinizada y aguas convencionales, y con reutilización controlada del agua y los nutrientes.
No full textDatos del proyecto "Optimización del fertirriego en cultivos hidropónicos con mezcla de agua desalinizada y aguas convencionales, y con reutilización controlada del agua y los nutrientes (PID2020-118492RB-C21)" de los cultivos llevados a cabo de TOMATE y CALABACÍ
Gemcitabine-monophosphate encapsulation in “stealth” MOFs effectively inhibits tumor growth in vivo
No full textGemcitabine is a commonly used chemotherapeutic agent that faces limitations due to rapid clearance, limited stability, and significant adverse effects. Recent efforts in its nanoencapsulation within Metal Organic Frameworks (MOFs) aim to overcome these barriers, offering a promising platform due to MOFs’ high drug-loading capacity, green synthesis methods, and in vivo biocompatibility. This study further explores the use of dextran-alendronate-PEG (DAP) coating to enhance MOF colloidal stability while maintaining substantial drug loading in the MOFs. Here, we demonstrate that DAP is essential for preventing the degradation of MOFs and enhancing their colloidal stability, enabling them to evade the mononuclear phagocytic system. The results also confirm that a high gemcitabine drug loading is preserved in DAP-coated MOFs. Furthermore, encapsulation improves the efficacy of the drug, as evidenced by a threefold decrease in the IC50 in prostate cancer cells compared to the free drug. Additionally, the use of the chorioallantoic membrane (CAM) assay, an alternative in vivo preclinical model, confirms that only gemcitabine-loaded MOFs effectively inhibit tumor growth. This work provides valuable insights into a biocompatible drug delivery system that improves the stability and therapeutic outcomes of gemcitabine in biological environments
Overepresentation and exclusionary practices of the foreign school community in special education in Spain
No full textThe presence of minorities in the socalled “special education” has always been a controversial issue. International literature has been reflecting a disproportionate presence of these groups in “special education”, but in Spain we lack indepth studies on the issue. In this article, we investigate a possible disproportionate presence of foreign nationals in “special education” in Spain. Applying statistical criteria such as the zscore to the data set of national and foreign population, we can show that differences are significant, especially for certain nationalities in terms of such disproportion. In conclusions, we reflect on how this disproportionality is part of the mechanisms of the construction of difference in the management of diversity in schools
Association between musculoskeletal symptoms and psychosocial factors in tropical crop workers of Spain using standardized Nordic questionnaire and Mini Psychosocial Factors method
No full textSouthern Spain (Andalusia) is the only region in Europe capable of producing tropical fruits (avocado, cheri-moya, and mango). The sector employs more than 4000 workers. The objective of this research is the integrated assessment of musculoskeletal symptoms and psychosocial factors of tropical crop workers in Andalusia using the ’Standardised Nordic questionnaires for the analysis of musculoskeletal symptoms (NMQ)’ and ’Mini Psycho-social Factors (MPF) method’. NMQ is a 28-question multiple-choice questionnaire covering the neck, shoulders, elbows, wrists/hands, back, hips, knees, and ankles. The MPF method comprises 15 questions and analyses a total of 12 psychosocial variables (Autonomy, Compensation, Control, Demands, Emotional, Health, Mental Load, Mobbing, Recognition, Relationships, Rhythm, and Support). In total, 401 interviews were completed with an error/accuracy of 4.66%. The method for selecting the agricultural plots where the workers work was carried out in a random, non-stratified way using UTM (Universal Transverse Mercator) coordinates. Multiple corre-spondence analysis, the Burt table, and descriptive statistics (with a chi-square test) were used to analyse the results. The results indicate that no high risk exists in any of the psychosocial factor although there is a medium risk. The psychosocial factor "Compensation" stands out. Musculoskeletal symptoms are identified in the back and neck. The symptoms do not prevent the workers from performing their agricultural tasks. Furthermore, the drought conditions over the last three agricultural seasons had the impact of decreasing agricultural wages, and this was slightly detected as an effect on the workers’ moral and economic recognition
An Ehrling-type inequality for the closed injective hull of Bloch ideals
No full textThe concept of injective hull of ideals of normalized Bloch mappings is introduced and a characterization is established in terms of a domination property. The injective hulls of normalized Bloch ideals generated by the procedures of composition and duality are described and applied to concrete examples of normalized Bloch ideals. A Bloch variant of a known characterization due to Jarchow and Pelczy\'nski for the closed injective hull of an operator ideal is stated in terms of an Ehrling-type inequality
Does Migration Lead to Acculturation of Gender-Related Attitudes? Gender Stereotypes, Perceived Gender Inequality, and Support for Collective Actions Toward Gender Equality
No full textThis study examines whether residing in a more gender-equal country
(Spain) influences Romanian immigrants’ gender-related attitudes.
Participants (N=572; 202 Romanian immigrants, 187 Spaniards, 183
Romanians) completed an online questionnaire. Results show that, compared to Romanians, immigrants perceived: a) agentic roles in the household as less traditional and, in turn, attributed men more immorality; b)
communal roles in the household as less traditional and, consequently,
attributed men less immorality and women less sociability; c) manifested
higher support for gender equality collective actions when gender inequality was perceived as low. Implications of the acculturation process of gender-related attitudes are discussed
Analisis Reaktivitas Thorium Molten Salt Reactor 500 Berdasarkan Skenario Penggunaan Control Rod Menggunakan OpenMC
Full text linkNeutron calculation simulation with the TMSR-500 conceptual reactor model was carried out for the development of reactivity control in the reactor. The control of reactivity is regulated by the use of a control rod for the shutdown rod and a regulating rod on the reactor. The simulation was carried out using OpenMC computational code and the nuclear data ENDF/B-VII.1. The reactivity value is calculated based on the use scenario of the control rod for each reactor operating condition set with a reactivity margin limit of ≤ 5% dk/k to control reactivity during operation and ≤ 0,5% dk/k during shutdown. The simulation of reactivity control during operation was calculated based on the use scenario of 0% Gd2O3-100% graphite, 25% Gd2O3-75% graphite, 50% Gd2O3-50% graphite, 75% Gd2O3-25% graphite, and 100% Gd2O3-0% graphite. Then, in the shutdown condition, the scenario is set with the use of control rods by Gd2O3 and graphite. The simulation results show that the reactor has an excess reactivity of >5% dk/k. The Control Safety Device (CSD) simulation is able to suppress reactivity ≤ 5% dk/k, but the flux distribution is unevenly distributed. The results of the calculation on the optimization the reactor by the fuel radius with the scenario of using a control rod of 25% graphite-75% Gd2O3 succeeded in controlling the reactivity with a margin of 1,0111±0,00013 (0,108% dk/k). Based on the research, the criticality level of the TMSR 500 is determined by the optimization of the fuel radius and the reactivity can be controlled based on the use scenario of the control rod.PT ThorCon dengan model reaktor konseptual TMSR-500 pada desainnya memerlukan pengembangan lebih lanjut terkait pengoperasian reaktor. Pengembangan lebih lanjut dengan tinjauan neutronik pada desain dilakukan dengan simulasi pengendalian reaktivitas pada reaktor. Pengendalian reaktivitas diatur oleh penggunaan control rod untuk shutdown rod dan regulating rod pada reaktor. Simulasi dilakukan menggunakan kode komputasi OpenMC dan daftar pustaka nuklir ENDF/B-VII.1. Nilai reaktivitas dihitung berdasarkan skenario penggunaan control rod untuk setiap kondisi pengoperasian reaktor yang diatur dengan batas margin reaktivitas ≤ 5% dk/k untuk mengontrol reaktivitas pada saat beroperasi dan ≤ 0,5% dk/k pada saat shutdown. Simulasi pengendalian reaktivitas pada saat beroperasi dihitung berdasarkan skenario penggunaan variasi control rod 0% Gd2O3-100% grafit, 25% Gd2O3-75% grafit, 50% Gd2O3-50% grafit, 75% Gd2O3-25% grafit, dan 100% Gd2O3-0% grafit. Kemudian, pada kondisi shutdown skenario diatur dengan penggunaan control rod oleh Gd2O3 dan grafit. Hasil simulasi menunjukan bahwa reaktor memiliki reaktivitas berlebih >5% dk/k. Simulasi Control Safety Device (CSD) mampu menekan reaktivitas ≤ 5% dk/k, akan tetapi distribusi fluks tersebar secara tidak merata. Hasil perhitungan pada optimalisasi teras reaktor beroperasi dengan skenario penggunaan control rod 25% grafit-75% Gd2O3 berhasil mengendalikan reaktivitas dengan margin 1.00111±0.00013 (0.1108% dk/k). Berdasarkan penelitian, tingkat kekritisan reaktor ThorCon ditentukan oleh optimalisasi radius fuel dan reaktivitas dapat dikendalikan berdasarkan skenario penggunaan control rod
Efek Penambahan Plutonium pada Sel Bahan Bakar MOX terhadap Performa Reaktor GFR 250MWth
Full text linkA fast-type reactor that operates on high-speed neutrons, GFR (Gas-cooled Fast Reactor) can produce various fissile materials and fertilizers. This production capability is very beneficial for the stability of nuclear fuel in the reactor core, especially reactors that use closed cycles such as GFR. Plutonium (Pu) from the residue from burning reactors such as PWR or LWR can be used as a mixed fuel to increase fissile nuclides in MOX fuel. MOX (Mixed Oxide) is a mixture of uranium (U) and plutonium (Pu) in certain amounts. The composition of plutonium (Pu) in MOX greatly influences the level of fuel combustion in the core at the start of operation. The research aims to vary the percentage of plutonium (Pu) to enable design adjustments to maximize fuel use efficiency. Simulations were conducted computationally to determine the performance of each percentage of Pu used in MOX. Depletion calculations were carried out for 10 years using the OpenMC code and ENDF/B VIII.0 nuclear data. The research results show that the best design performance is at a Pu percentage of 11% which is determined based on the range of effective multiplication factor (keff ) values and excess reactivity and is in line with expectations.Reaktor tipe cepat yang beroperasi pada neutron berkecepatan tinggi, GFR (Gas-cooled Fast Reactor) dapat memproduksi berbagai macam campuran bahan fisil dan fertil. Kemampuan produksi tersebut sangat bermanfaat bagi kestabilan bahan bakar nuklir di dalam teras reaktor khususnya reaktor yang menggunakan siklus tertutup seperti GFR. Plutonium (Pu) dari residu hasil pembakaran reaktor seperti PWR atau LWR dapat digunakan sebagai bahan bakar campuran untuk meningkatkan nuklida fisil pada bahan bakar MOX. MOX (Mixed Oxide) adalah campuran antara uranium (U) dan plutonium (Pu) dalam jumlah tertentu. Komposisi plutonium (Pu) dalam MOX sangat berpengaruh terhadap tingkat pembakaran bahan bakar dalam teras di awal operasi. Tujuan penelitian yaitu melakukan variasi persentase plutonium (Pu) agar memungkinkan dilakukannya penyesuain desain untuk memaksimalkan efisinsi penggunaan bahan bakar. Simulasi dilakukan secara komputasi untuk menentukan performa dari masing-masing persentase Pu yang digunakan pada MOX. Perhitungan deplesi dilakukan selama 10 tahun menggunakan kode OpenMC dan data nuklir ENDF/B VIII.0. Hasil penelitian menunjukkan performa desain paling baik adalah pada persentase Pu 11% yang ditentukan berdasarkan keluran nilai faktor multiplikasi effektif (keff) dan excess reactivity serta sesuai dengan yang diharapkan
Peningkatan Kualitas Bio-Oil Hasil Pirolisis Cangkang Kelapa Sawit Berstandar Pelumas Organik
Full text linkPalm kernel shells are biomass waste that has the potential to be processed into bio-oil through pyrolysis, but its quality needs to be improved to meet organic lubricant standards. This study aims to improve the quality of bio-oil through a transesterification process with activated carbon-NaOH catalyst and the addition of guar gum as a thickening agent. Pyrolysis was carried out at a temperature of 300°C for 60 minutes, and transesterification at a temperature of 60°C for 2 hours with a methanol:bio-oil ratio of 6:1. The results showed that increasing the amount of catalyst up to 10% increased the yield of methyl ester, while the addition of guar gum increased the kinematic viscosity to 7.9 cst, approaching commercial lubricant standards such as top 1 Evo 5W-30 and pertamina fastron gold 5W-30. However, the flash point is still lower than industrial lubricants. Thus, the quality of bio-oil from palm kernel shell pyrolysis can be improved to approach organic lubricant standards, making it a more environmentally friendly alternative lubricant and has the potential for industrial applications.Cangkang kelapa sawit merupakan limbah biomassa yang berpotensi diolah menjadi bio-oil melalui pirolisis, namun kualitasnya perlu ditingkatkan agar sesuai dengan standar pelumas organik. Penelitian ini bertujuan meningkatkan kualitas bio-oil melalui proses transesterifikasi dengan katalis karbon aktif-NaOH serta penambahan guar gum sebagai agen pengental. Pirolisis dilakukan pada suhu 300°C selama 60 menit, dan transesterifikasi pada suhu 60°C selama 2 jam dengan rasio metanol:bio-oil 6:1. Hasil penelitian menunjukkan bahwa peningkatan jumlah katalis hingga 10% meningkatkan yield metil ester, sementara penambahan guar gum meningkatkan viskositas kinematik hingga 7,9 cst, mendekati standar pelumas komersial seperti top 1 Evo 5W-30 dan pertamina fastron gold 5W-30. namun, titik nyala masih lebih rendah dibandingkan pelumas industri. dengan demikian, bio-oil hasil pirolisis cangkang kelapa sawit dapat ditingkatkan kualitasnya hingga mendekati standar pelumas organik, menjadikannya alternatif pelumas yang lebih ramah lingkungan dan berpotensi untuk aplikasi industri