Judul: Erapan Fraksi Klei+kleinano Tuf Volkan Gunung Salak terhadap Fosfat dan Nitrat dalam Air Limbah Industri
Abstrak: Pada penelitian sebelumnya, dari tuf volkan G. Salak dapat diekstraksi fraksi klei (k, berdiameter <2 μm) dan kleinano (kn, berdiameter <200 nm) bermuatan dominan positif sehingga dapat dimanfaatkan sebagai flokulan anionik. Erapan fraksi kn terhadap fosfat (PO43-) dan nitrat (NO3-) dilaporkan lebih tinggi daripada fraksi k namun pemisahannya membutuhkan waktu lama. Penelitian ini bertujuan menguji erapan gabungan fraksi klei+kleinano (kkn) tuf volkan G. Salak terhadap fosfat dan nitrat dalam air limbah industri. Dari profil tuf volkan G. Salak (tv) lapisan 3 dan 4 terekstrak 4.8428 mg kkn3/g tv (45,38% k dan 54,62% kn) dan 8,3125 mg kkn4/g tv (35,91% k dan 64,09% kn). Erapan maksimum kkn3 dan kkn4 adalah 14,27 mg P limbah/g kkn3 serta 26,60 mg NO3- limbah/g kkn3 dan 6,78 mg P limbah/g kkn4 serta 10,68 mg NO3- limbah/g kkn4. Erapan maksimum kkn3 dan kkn4 terhadap P dan nitrat limbah lebih rendah daripada P dan nitrat inorganik. Penurunan P limbah dari 23,63 ke 1,00 mg P/L agar sesuai baku mutu perairan kelas III PP No. 82/2001 membutuhkan 2,776 g kkn3/L atau 2,09 g kkn4/ L. Hal yang sama untuk nitrat tidak dapat ditetapkan karena kadar nitrat limbah (30,85 mg NO3-/L) sudah lebih rendah dari baku mutunya (88,57 mg NO3-/L).
Keyword: clay+nanoclay fraction, industrial waste water, nitrate, phosphate, sorption

Judul: Erapan Fraksi Klei+kleinano Tuf Volkan Gunung Salak terhadap Fosfat dan Nitrat dalam Air Limbah Industri
Abstrak: In the previous researches, it could be extracted from volcanic tuff of M. Salak clay (c, diameter <2 μm) and nanoclay (nc, diameter <200 nm) fractions with the dominant positive charge so that it could be used as an anionic flocculent. Sorption of phosphate (PO43-) and nitrate (NO3-) on cn was reported to be higher than those on c but their separation processes took a long time. This research aimed at to evaluate sorption of PO43- and NO3- in industrial wastewater (ww) on the combined clay+nanoclay (cnc) fractions of M. Salak volcanic tuff. From the 3rd and 4th layer of M. Salak volcanic tuff profile (tv), it was extracted 4.8428 mg cnc3/g tv (45.38% c and 54.62% nc) and 8.3125 mg cnc4/g tv (35.91% c and 64.09% nc). Maximum sorption of cnc3 and cnc4 were respectively 14.27 mg ww-P/g cnc3 and 26.60 mg ww-NO3-/g cnc3 and 6.78 mg ww-P/g cnc4 and 10.68 mg ww-NO3-/g cnc4. Maximum sorption of ww-P and -nitrate on cnc3 and cnc4 were lower than those of inorganic-P and -nitrate. Reduction in ww-P from 23.63 to 1.00 mg P/L as to comply with the quality standard of water class III according to the GOI Regulation No. 82/2001 required 2.776 g cnc3/L or 2.09 g cnc4/L. The same thing for nitrate could not be determined because ww-NO3- (30.85 mg/L) was already lower than its quality standard (88.57 mg NO3-/L).
Keyword: sorption, phosphate, nitrate, industrial waste water, clay+nanoclay fraction

Judul: Comparison of HIV Model with and without Time Delay
Abstrak: Acquired immunodeficiency syndrome (AIDS) is the reduction of the human immune system. AIDS is caused by human immunodeficiency virus (HIV). No medicine has been found for this desease until recently. An AIDS therapy is usually performed with highly active antiretroviral therapy, namely reverse transcriptase inhibitors, protease inhibitors and combination of both. Various models have been developed to explain the immune system of patients with AIDS, namely the HIV, response and the time delay model. This paper discusses the comparison between the dynamics of the HIV virus, the dynamic response of protease inhibitors and dynamics of time delay. The dynamics model of HIV is influenced by the level of white blood cells produced and the rate of its death. Dynamics of protease inhibitors on the response and the time delay model is influenced by the death rate of infected white blood cells and the failure rate of treatment.
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