Judul: Pengembangan sistem evaluasi buah manggis secara non destruktif dengan gelombang ultrasonik
Abstrak: Mangosteen remains at the highest value among the exported Indonesian fruits amounting to 9.31 million USD in 2003. However, claim for inner quality remove fruits with low inner quality is often imposed to Indonesian mangosteen. Sortation is critically required to remove fruits with low inner quality such as gamboges, translucent or defect. The objective of this study was to asses the ultrasonic characteristics related to physio-chamical properties of mangosteen for non-destructive evaluation of the fruit.
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Judul: Kajian Sifat Akustik Gelombang Ultrasonik Sebagai Identifikasi Mutu Non Destruktif pada Tiga Jenis Manggis
Abstrak: Mangosteen (Garcinia mangostana L) fruits grade one with diameter 55-65 mm from three locations (Bogor, Purwakarta, and Sukabumi) were stored at the room temperature. The objectives of this research are to identify quality degradation of three types of mangosteen by analyzing of the acoustic character of ultrasonic wave. As results, quality degradation was found significantly at 9th day of storage period when increasing of color value (brightness) and the firmness occur simultaneously with decreasing of the value of total soluble solids. On the maturity process of mangosteens, ultrasonic velocity and total soluble solids increased while attenuation and the value of firmness decreased. Range values of wave velocity are transmitted in the sample group mangosteen Bogor, Purwakarta, and Sukabumi respectively 221.60-282.15 m/s, 243.27-334.54 m/s, and 214.36- 244.10 m/s. Range attenuation coefficient values for the sample group mangosteen Bogor, Purwakarta, and Sukabumi respectively 19.98-25.17 dB/m, 15.46-24.04 dB/m, and 13.97-22.30 dB/m.
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Judul: Model’s Dynamics for Lymphocytes Recovery on the HIV presence with Protease Inhibitor Therapy.
Abstrak: HIV is a member of retrovirus that especially attacks lymphocytes or white blood cells, known as CD4+ T cells. New T cells created from sources within the body such as the thymus and by proliferation of existing T cells. In this paper, influence of protease inhibitor therapy in HIV dynamics will be analyzed. The influence can be categoried in three models, which are model HIV without drug therapy, model HIV with protease inhibitor and model T cell recovery. In the models, three parameters which are uninfected cells population, infected cells population and virus population are studied. From HIV without drug therapy model it is obtained two types fixed point which are uninfected fixed point and infected fixed point. The stability of fixed point depends on basic reproduction number which is influenceed by the total number of virus produced by a cell during its lifetime. From HIV with protease inhibitor therapy model it is obtained two type fixed points. The stability of fixed point depends on basic reproduction number. Other than influenceed by the total number of virus produced by a cell during its lifetime, basic reproduction number of this model also affected by the effectiveness of a protease inhibitor. Basic reproduction number of this model is smaller than that of model HIV without drug therapy. In the model T cell recovery, new T cells created only from sources within the body, and T cells can be invulnerable to HIV infection after the therapy. From the model it is obtained only one fixed point that is uninfected fixed point. The stability of fixed point depends on basic reproduction number. The total number of virus produced by a cell during its lifetime and the effectiveness of a protease inhibitor determine the basic reproduction number. Basic reproduction number of this model is smallest than that of other models.
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