Thermodynamic stability of fluid-fluid phase separation in binary athermal mixtures: The role of nonadditivity

We study the thermodynamic stability of fluid-fluid phase separation in binary nonadditive mixtures of hard-spheres for moderate size ratios. We are interested in elucidating the role played by small amounts of nonadditivity in determining the stability of fluid-fluid phase separation with respect to the fluid-solid phase transition. The demixing curves are built in the framework of the modified-hypernetted chain and of the Rogers-Young integral equation theories through the calculation of the Gibbs free energy. We also evaluate fluid-fluid phase equilibria within a first-order thermodynamic perturbation theory applied to an effective one-component potential obtained by integrating out the degrees of freedom of the small spheres. A qualitative agreement emerges between the two different approaches. We also address the determination of the freezing line by applying the first-order thermodynamic perturbation theory to the effective interaction between large spheres. Our results suggest that for intermediate size ratios a modest amount of nonadditivity, smaller than earlier thought, can be sufficient to drive the fluid-fluid critical point into the thermodinamically stable region of the phase diagram. These findings could be significant for rare-gas mixtures in extreme pressure and temperature conditions, where nonadditivity is expected to be rather small.Comment: 17 pages, 7 figures, to appear in J. Phys. Chem.

Entropy-based measure of structural order in water

We analyze the nature of the structural order established in liquid TIP4P water in the framework provided by the multi-particle correlation expansion of the statistical entropy. Different regimes are mapped onto the phase diagram of the model upon resolving the pair entropy into its translational and orientational components. These parameters are used to quantify the relative amounts of positional and angular order in a given thermodynamic state, thus allowing a structurally unbiased definition of low-density and high-density water. As a result, the structurally anomalous region within which both types of order are simultaneously disrupted by an increase of pressure at constant temperature is clearly identified through extensive molecular-dynamics simulations.Comment: 5 pages, 2 figures, to appear in Phys. Rev. E (Rapid Communication

ANALISIS PERILAKU SEKSUAL REMAJA LAKI-LAKI DAN PEREMPUAN DI KOTA AMBON

Masa remaja ditandai dengan mulai berani untuk menjalin hubungan khusus dengan lawan jenis yang biasa disebut pacaran. Pacaran merupakan salah satu cara yang paling banyak dilakukan dan paling mudah untuk menggiring remaja ke perilaku seksual berisiko. Tujuan penelitian adalah untuk menganalisis perilaku seksual remaja laki-laki dan perempuan di Kota Ambon. Penelitian ini merupakan penelitian kuantitatif dengan pendekatan cross sectional. Populasi penelitian merupakan remaja di Kota Ambon. Sampel penelitian adalah siswa Sekolah Menengah Atas (SMA)/sederajat di Kota Ambon. Penelitian menggunakan quote sampling dengan sampel sebanyak 50 siswa tiap sekolah. Jumlah sampel sebanyak 1.000 siswa SMA/sederajat yang diambil dari 20 sekolah di Kota Ambon.  Hasil penelitian menemukan bahwa sekitar 62,1% remaja pernah menonton video porno dan sekitar 42,7% beranggapan bahwa berpelukan adalah hal yang biasa, sekitar 10,8% remaja pernah melakukan hubungan seksual pranikah. Remaja laki-laki yang memiliki perilaku seksual berisiko sebesar 61,4% sedangkan remaja perempuan yang memiliki perilaku seksual berisiko yaitu 26,4%. Kesimpulannya adalah ada hubungan jenis kelamin dengan perilaku seksual berisiko pada remaja di Kota Ambon (p<0,001). Disarankan bagi guru dan orang tua dapat mengawasi perilaku remaja sehingga tidak terjerumus melakukan perilaku seksual berisiko

APPLICATION OF ARTIFICIAL NEURAL NETWORK BACKPROPAGATION TO PREDICT HOUSEHOLD CONSUMPTION OF ELECTRICITY IN AMBON

Electricity is one of the energy most widely used in the universe. Electric power demand in Ambon city tends to increase due to the growing of population in Ambon. The necessary of electricity power in Ambon City by utilizing two systems are interconnected such as: PLTD Poka and PLTD Hative Kecil (Galala). In this research forecast the demand for household electricity consumption in 2016 based on validation data from 2011-2015 using Application of Neural Networks Backpropagation method. The validation data are using in JST-Backpropagation training, with the best network architecture that is 20 10 5 1 neurons and 0.8 learning rate, can produce the best pattern with the accuracy is 75% and the value of Mean Square Error is 0.298335.&nbsp

Hubungan Pengetahuan, Sikap dan Perilaku Masyarakat dengan Kesediaan dalam Mengikuti Vaksinasi COVID-19

Coronavirus disease 2019 or commonly called COVID-19 is an infectious disease that is now a global pandemic. COVID-19 is now a serious problem all over the world, the number of cases is also increasing every day. Therefore, it is not only necessary to intervene in the implementation of health procedures but also to immediately take other effective intervention measures to stop the spread of disease, namely through vaccination efforts. This study aims to determine the relationship between knowledge, attitudes and community behavior towards COVID-19 vaccination with willingness to participate in COVID-19 vaccination in Passo Village in 2022. This research is a quantitative analytic study using a cross sectional research design. Samples were taken as many as 100 people using a combination of purposive sampling and stratified sampling methods. The results showed that knowledge about the COVID-19 vaccine was 44% (currently), community attitudes towards the COVID-19 vaccination program were 71% (good), community behavior towards COVID-19 prevention was 75% (good) and willingness to participate in the COVID-19 vaccination was 75 % (willing to be vaccinated against COVID-19). The results of the bivariate analysis using the chi-square stated that there was a significant relationship between knowledge (p=0.024), attitude (p=0.027) and behavior (p=0.006) with willingness to participate in COVID-19 vaccination in the village in 2022

The activation of non-linear optical response in Ag@ZnO nanocolloids under an external highly intense electric field

An extensive theoretical and experimental study of the non-linear optical properties of bare and silver-decorated zinc oxide (ZnO and Ag@ZnO) nanostructures, prepared by laser-generated plasmas in water and in water/polyvinyl alcohol (PVA) solutions, is reported. The z-scan technique was used to monitor the activation of the non-linear optical mechanisms, focusing an intense laser radiation through the nanocolloids under study. A classical formalism was adopted to explain the z-scan data of these anisotropic materials and to describe the influence of radiation torque and forces on the optically activated nanostructures. This modelling approach includes effects of nanoparticles rearrangements, also taking into account plasmonic effects. An interesting coupling between the nature of the optical limiting response and the nanostructures reorganization under the high-power laser excitation, used during the z-scan measurements, was found and, for the first time to our knowledge, was explained using a classical theoretical approach

HUBUNGAN CULTURE SHOCK DENGAN PENYESUAIAN DIRI MAHASISWA PERANTAU SEMESTER PERTAMA TAHUN 2020 DAN 2021 DI FAKULTAS KEDOKTERAN UNIVERSITAS PATTIMURA AMBON

Mahasiswa perantauan yang mengalami culture shock saat memasuki tahap awal kehidupan di lingkungan baru merupakan reaksi karena menemukan perbedaan budaya yang berpotensi mengakibatkan kesulitan penyesuaian seperti kurang melakukan interaksi, memiliki prasangka negatif, serta dapat mengakibatkan stres yang menyebabkan terjadinya culture shock. Culture shock dapat diatasi bila seorang individu mampu beradaptasi dan menyesuaikan diri dengan budaya tempat individu berada. Tujuan dari penelitian ini adalah untuk mengetahui ada tidaknya hubungan culture Shock dengan penyesuaian diri mahasiswa perantau semester pertama tahun 2020 dan 2021 di Fakultas Kedokteran Universitas Pattimura Ambon. Jenis penelitian ini adalah penelitian analitik menggunakan data primer dengan pendekatan cross sectional. Sampel dalam penelitian ini adalah mahasiswa fakultas kedokteran angkatan 2020 dan 2021 yang berasal dari luar Maluku berjumlah 107 mahasiswa yang kemudian diberikan link google form yang berisi kuesioner untuk diisi. Data yang diperoleh kemudian akan dianalisis secara univariat dan bivariat. Hasil penelitian menunjukkan bahwa responden yang banyak di temukan adalah perempuan yaitu 86 responden (80,37%), usia responden yang paling banyak ditemukan adalah 18 – 20 tahun sebanyak 93 responden (86,9%), provinsi asal responden yang paling banyak adalah provinsi Sulawesi Selatan yaitu 22 responden (20,6%) dan mayoritas tempat tinggal responden adalah kosan yaitu 88 responden (82,2%). Tingkat culture shock mahasiswa berada pada kategori sedang yaitu 85 responden (79,44%) dan penyesuain diri mahasiswa juga berada pada kategori sedang yaitu 65 responden (60,75%). Terdapat hubungan yang signifikan antara culture shock dengan penyesuaian diri mahasiswa