Potensi Ekstrak Etanol Biji Alpukat (Persea Americana Mill.) sebagai Tabir Surya

Telah dilakukan penelitian potensi ekstrak etanol biji alpukat sebagai tabir surya. Tujuan dari penelitian ini untuk menentukan nilai Sun Protection Factor (SPF) ekstrak etanol biji alpukat (Persea americana Mill.). Simplisia biji diekstraksi dengan metode maserasi menggunakan larutan penyari etanol 96%, kemudian dibuat larutan sampel dengan seri konsentrasi 200, 400, 600, 800 dan 1000 ppm. Selanjutnya larutan sampel diukur absorbansinya panjang gelombang 290-320 nm dengan interval 5 nm. Hasil penelitian menunjukkan ekstrak etanol biji alpukat 1000 ppm memiliki nilai SPF tertinggi yaitu 8,02, yang terkategori proteksi maksimal

Effect of Casting and Mould Cooling Temperatures on the Warping Phenomenon of Aluminium at High Pressure Die- Casting

Abstract. The effect of molten aluminium pouring temperature and hot oiltemperature for mould heating and cooling on the warping phenomenon ofthick-thin section aluminium high-pressure die-casting process was investigatedon a four cavities hard disk drive mould. Nine combinations of moltenaluminium A380 pouring temperature of 660ºC, 690ºC and 720ºC and hot oiltemperature of 150ºC, 200ºC and 250ºC were being studied. Magmasoftsimulation software was used to simulate the molten aluminium flow in themould and distortion to understand the die-casting cooling pattern in responseto different molten aluminium temperature and mould cooling parameterssettings. Actual casting was carried out to produce the parts according tosimulation settings. Warping data was collected and analysed using Minitab 17.It was found that each mould cavity had different cooling pattern resulting indifferent warping magnitude. Pouring temperature at 660ºC and 720ºC both hadhigher warping distortion then 690ºC. Hot oil temperature at 150ºC had higherwarping distortion than 200ºC and 250ºC. The lowest warping distortion wasestablish at molten aluminium pouring and hot oil temperature of 690ºC and200ºC respectively

LIQUORICE BEVERAGE EFFECT ON THE PHARMACOKINETIC PARAMETERS OF ATORVASTATIN, SIMVASTATIN, AND LOVASTATIN BY LIQUID CHROMATOGRAPHY-MASS SPECTROSCOPY/MASS SPECTROSCOPY

ABSTRACTObjective: The objective of this study is to examine the effects of pre-consumption of freshly prepared liquorice beverage (4 ml/kg) on thepharmacokinetic (PK) parameters of (80 mg/kg) oral dose of atorvastatin, simvastatin, and lovastatin in healthy rats plasma.Methods: A simple, rapid, and applicable analytical method was developed for the determination of each statin in rats' plasma. This method usesliquid chromatography-mass spectroscopy/mass spectroscopy. The mobile phase composed of methanol and formic acid in water and glimepiride asan internal standard. 108 rats were used in this study. Liquorice juice was given, and then each of the statins was given to test groups and liquoriceonly to the control groups, and then plasma samples were withdrawn on specific time schedule then PK analysis was performed.Results: The analytical method showed acceptable linearity, recovery, precision, and accuracy. Administration of liquorice resulted in a significantincrease in maximum concentration in plasma (C) of the three statins, also the area under plasma level-time curves (area under curve) was increasedsignificantly. Moreover, the bioavailability of the drugs. On the other hand, the elimination of the three drugs showed no great changes, which suggestsan interaction between liquorice and the transporting system of statins on the gut and biliary wall.maxConclusion: Consumption of liquorice results in increase bioavailability of atorvastatin, simvastatin, and lovastatin.Keywords: Liquorice, Atorvastatin, Liquid chromatography-mass spectroscopy/mass spectroscopy, Simvastatin, Lovastatin, Pharmacokineticparameters

Energy efficiency of permeate gap and novel conductive gap membrane distillation

This work presents numerical modeling results and flux experiments for a novel membrane distillation configuration called conductive gap membrane distillation (CGMD), as well as permeate gap membrane distillation (PGMD). CGMD has a conductive spacer in the gap between the membrane and condensing surface rather than more commonly used insulating materials. Flux measurements with two experimental systems are used to validate the numerical models for PGMD and CGMD. PGMD has 20% higher GOR (energy efficiency) than an air gap membrane distillation (AGMD) system of the same size, whereas CGMD can have two times higher GOR than even PGMD. Increasing gap effective thermal conductivity in CGMD has negligible benefits beyond View the MathML source under the conditions of this study. The direction of pure water flow in the gap has a significant influence on overall system energy efficiency, especially in the case of CGMD. Using a countercurrent configuration for the pure water flow in the gap relative to the cold stream leads to 40% higher GOR than flow cocurrent with the cold water stream.MIT & Masdar Institute Cooperative Program (Reference no. 02/MI/MI/CP/11/07633/ GEN/G/00

Shell mould strength of rice husk ash (RHA) and bentonite clays in investment casting

Investment casting process (IC) plays a major role in the modern manufacturing process in providing an economical means of mass production components with intricate shape and complex geometry as demand in various crucial applications including aerospace, automotive, military, biomedical and others. This casting technique, develop shell mould fabrication by coating the required pattern with a refractory mixture which offers the complex geometrical shape and sizes parts to be cast. However, the modern IC approach in shell mould production suffers from zircon's cost and supply instability as it is the main material to be used. Zircon uses as refractory filler for slurry production, and also in the form of sand used as stucco particles, is favoured by the investment casting facilities and industries as it exhibits the most versatile properties such as low thermal expansion and low reactivity to the metal to be cast. During the period of zircon supply shortage, many facilities introduce several alternatives. Currently, the step taken to reduce the cost of primary slurry material is by using some alternate refractory material like, alumina, silica, to be used with zircon for shell mould production. In relation to that, several researches continue to search for alternatives approach for shell mould materials. This research introduces the alternative method in fabricating investment casting shell mould as recognized from investment casting industry located in Sungai Puar of Bukittingi Padang Indonesia. This industry employs several local resources to fabricate the shell mould. These materials consist of rice husk ash (RHA), and two types of bentonite clays. The bentonite clays were obtained nearly from Kota Payakumbuh in the western provinces. However, this industry suffers from weak shell mould strength and need to be investigated and consulted. In this paper, the investigation on shell mould strength made from rice husk ash (RHA), and bentonite clays were conducted. The strength was measured by its modulus of rupture (MOR) performed in 3 points flexural bending test. The green and fired shell mould strength was determined from five type of slurry composition. The results revealed that the highest green and fired strength obtained were 0.157 MPa and 0.361 MPa from shell mould sample C of RHA (46%) and bentonite (54%) of its composition

Dynamics of fish diversity across an environmental gradient in the Seribu Islands reefs off Jakarta

Madduppa HH, Subhan B, Suparyani E, Siregar AM, Arafat D, Tarigan SA, Alimuddin, Khairudi D, Rahmawati F, Bramandito A. 2013. Dynamics of fish diversity across an environmental gradient in the Seribu Islands reefs off Jakarta. Biodiversitas 14: 17-24. The reefs of Seribu Islands have been affected by multitude of anthropogenic pressures. However, the biodiversity of reef fishes across the archipelago linked to environmental condition is poorly known. This study aimed to investigate the biodiversity and the trophic level of fish communities across the archipelago. The study on reef fish communities was conducted on 33 reef sites associated with islands or shoal randomly chosen from each zone along environmental gradients from the inshore water nearest of Jakarta Bay to the offshore water of the outer islands. The study sites represented each sub-districts within the archipelago, namely Pari, Tidung, Panggang, Kelapa, and Harapan. A total of 46,263 individual fishes were counted, belonging to 216 species and 29 families. The multivariate analysis of fish abundance using the Bray Curtis similarity index and non-metric multidimensional scaling (MDS) clearly showed the clustering of sub-districts, near and far from Jakarta Bay. The results showed that the sub-districts can be clustered into three groups. Group one consists of one sub-district (Pari) located in the southern part of the Seribu Islands near Jakarta Bay. Group two consists of three sub-districts (Tidung, Panggang, Kelapa) located in mid of the archipelago. The third group consists of one sub-district (Harapan) located in the northern part of the Seribu Islands. Based on species richness and fish diversity indices, the sub-districts can be clustered into two groups (1 = Pari and Tidung, 2 = Panggang Kelapa, Harapan). However, levels of similarities among sub-districts varied. The fish community in sub-district of Pari was dominated by carnivorous, omnivorous and herbivorous fishes, while those in the rest of sub-districts were dominated by omnivorous and carnivorous fishes. The present study results showed that the biodiversity of reef fishes across the Seribu Islands seemed to be linked to the environmental conditions

DETC2005-85376 MODELING THE TRANSIENT AND STEADY-STATE FLOW OVER A STATIONARY CYLINDER

ABSTRACT

Optimization, Purification and Physicochemical Characterization of Curdlan Produced by Paenibacillus sp. Strain NBR-10

In recent years, significant progress has been done to discover a novel microbial exopolysaccharides that possess novel and highly functional properties. During our screening program for curdlan producing bacteria, 35 bacterial strains were isolated from 15 sandy soils collected from Rafha governorate, Northern Border region, Saudi Arabia. Among them isolate, NBR-10 was selected for its promising ability for curdlan production. The selected isolate was identified based on methods or results mentioned in this paper as Paenibacillus sp. For enhancing the curdlan yield produced by Paenibacillus sp. NBR-10, different culture conditions and medium compositions were optimized. It was found that, the maximum yield was obtained at 35 °C, initial pH 7 after 48 h of incubation. Also different carbon and nitrogen sources were used to improve the curdlan yield, it was indicated that sucrose and yeast extract were the best carbon and nitrogen sources respectively. Generally, optimization of the different parameters was approximately duplicated the curdlan yield from 2.34 g/l to 4.82 g/l. The precipitated curdlan dissolved in 2M NaOH exhibited high affinity to gel formation. Analysis of FT-IR, 1 H NMR and 13 C NMR spectra proved that the produced polymer by Paenibacillus sp. NBR-10 has β β β β β-(1-3)-D-glucan (curdlan) structure

The effects of iCVD film thickness and conformality on the permeability and wetting of MD membranes

Membranes possessing high permeability to water vapor and high liquid entry pressure (LEP) are necessary for efficient membrane distillation (MD) desalination. A common technique to prepare specialized MD membranes consists of coating a hydrophilic or hydrophobic base membrane with a low surface-energy material. This increases its liquid entry pressure, making the membrane suitable for MD. However, in addition to increasing LEP, the surface-coating may also decrease permeability of the membrane by reducing its average pore size. In this study, we quantify the effects of initiated chemical vapor deposition (iCVD) polymer coatings on membrane permeability and LEP. We consider whether the iCVD films should have minimized thickness or maximized non-conformality, in order to maximize the permeability achieved for a given value of LEP. We determined theoretically that permeability of a single pore is maximized with a highly non-conformal iCVD coating. However, the overall permeability of a membrane consisting of many pores is maximized when iCVD film thickness is minimized. We applied the findings experimentally, preparing an iCVD-treated track-etched polycarbonate (PCTE) membrane and testing it in a permeate gap membrane distillation (PCMD) system. This study focuses on membranes with clearly defined, cylindrical pores. However, we believe that the principles we discuss will extend to membranes with more complex pore architectures. Overall, this work indicates that the focus of surface-coating development should be on minimizing film thickness, not on increasing their non-conformality.MIT & Masdar Institute Cooperative Program (02/MI/MI/CP/11/07633/GEN/G/00)Massachusetts Institute of Technology. Institute for Soldier Nanotechnologies (W911NF-13-d-0001