Analisis Jalur Terhadap Faktor-faktor Yang Mempengaruhi Indeks Prestasi Kumulatif (Ipk) Mahasiswa Statistika Undip

Education is a priority thing everyone today. Education is implemented in learning, by learning humans can develop all the potential there is in him. Learning is always related to the achievement of learning, because learning is a process while learning achievement is the result of the learning process. In the course of learning achievement levels measured by GPA (Grade Point Average). Factors that influence GPA among allowance, age, value of the UN Senior High School, many organizations, the internet long, long time to learn. Path analysis is the development of multiple regression which the independent variables affect the dependent variable not only directly but also indirectly affect. Based on the results of the discussion of the factors that affect the GPA is concluded that the allowance has indirect effect of -0,211, age has direct effect of age at 0,1901, the UN has direct effect of 0,258, many organizations have a direct effect of -0,3582 and has indirect effect of -0,132, the internet long direct effect of -0,2376 and has indirect effect of -0,038, long learning has a direct effect of 0,2344

Co-occurrence of pectenotoxins and Dinophysis miles in an Indonesian semi-enclosed bay

The study aims to unravel the variability of Dinophysis spp. and their alleged toxins in conjunction with environmental drivers in Ambon Bay. Phytoplankton samples, lipophilic toxins and physiochemical water properties were analysed during a 1.5-year period. Three Dinophysis species (D. miles, D. caudata, and D. acuminata) were found in plankton samples, of which D. miles was the most abundant and persistently occurring species. Pectenotoxin-2 (PTX2) and its secoacid (PTX2sa) were detected throughout, and PTX2sa levels strongly correlated with D. miles cell abundance. The toxin showed a positive correlation with temperature, which may suggest that D. miles cells contain rather constant PTX2sa during warmer months. Dissolved nitrate concentrations were found to play a major role in regulating cell abundances and toxin levels. This study adds adequate information regarding marine biotoxins and potentially toxic species for future Harmful Algal Bloom management in Ambon and Indonesia at large

Prestasi pembakaran biodiesel berasaskan minyak bunga matahari ke atas pembakar berbahan api cecair

Kajian ini menyiasat mengenai prestasi pembakaran adunan bahan api biodiesel berasaskan minyak bunga matahari dengan diesel pada nisbah B10 (biodiesel 10%, diesel 90%), B15 (biodiesel 15%, diesel 85%), B25 (biodiesel 25%, diesel 75%) dan B50 (biodiesel 50%, diesel 50%). Prestasi pembakaran bahan api ini dinilai berdasarkan kepada nilai suhu dinding kebuk pembakar, kecekapan terma pembakar serta kepekatan gas emisi yang dibebaskan seperti oksida nitrogen (NOx), sulfur dioksida (SO2), dan karbon monoksida (CO). Bahan api adunan biodiesel berasaskan minyak bunga matahari diukur dan dibandingkan dengan diesel. Semua bahan api yang diuji dibakar menggunakan kebuk pembakaran terbuka pada lima nisbah kesetaraan yang berbeza, iaitu, keadaan cair bahan api (Ф = 0.8 dan 0.9), stoikiometri (Ф = 1.0), dan kaya bahan api (Ф = 1.1 dan 1.2). Hasil kajian menunjukkan bahawa bahan api biodiesel berasaskan minyak bunga matahari terbakar pada suhu yang lebih rendah. Ini menghasilkan tenaga terma bahan api dan kecekapan terma pembakar yang lebih rendah dari diesel. Selain itu, emisi yang dihasilkan adalah lebih rendah (kecuali NOx) berbanding dengan diesel untuk semua nisbah kesetaraan. Hasilnya juga menunjukkan bahawa penggunaan biodiesel adalah berguna untuk aplikasi moden yang berbeza, khususnya di sektor industri kerana ia lebih mesra alam dan boleh dijadikan sebagai pilihan alternatif kepada bahan api petroleum. The current study investigated the combustion performance of sunflower oil-based biodiesel fuel blends with diesel at the ratio of B10 (10% biodiesel, 90% diesel), B15 (15% biodiesel, 85% diesel), B25 (25% biodiesel, 75% diesel) and B50 (50% biodiesel, 50% diesel). The combustion performance of this fuel is evaluated based on the value of the combustion chamber wall temperature, the thermal efficiency of the burner as well as the concentration of emission gases released such as nitrogen oxides (NOx), sulfur dioxide (SO2), and carbon monoxide (CO). Sunflower oil-based biodiesel blend fuel was measured and compared to diesel. All fuels tested were burned using a combustion chamber with one of its ends open, at five different equivalence ratios, namely, fuellean condition (Ф = 0.8 and 0.9), stoichiometry (Ф = 1.0), and fuel-rich (Ф = 1.1 and 1.2). The results show that sunflower oil-based biodiesel fuels burn at lower temperatures. This results in lower fuel thermal energy, and thus, lower thermal efficiency of the burner compared to diesel. Moreover, the emissions produced are lower (except for NOx) compared to diesel for all equivalence ratios. The results also show that the use of biodiesel is useful for different modern applications, especially in the industrial sector as it is more environmentally friendly and can be used as an alternative to petroleum fuels

Hydrodynamic resistance analysis of new hull design for multipurpose amphibious vehicle applying with finite volume method

This paper numerically investigated the hydrodynamic resistance of Multipurpose Amphibious Vehicles (MAV) in three bow shapes to approach the better hull bow shape design. This type of vehicle and other blunt-shaped floating vehicles encounter the problem of a large bow wave forming at high speeds. This wave formation is accompanied by higher resistance and at a critical speed results in bow submergence or swamping. Three new shapes of hull bow design for the multipurpose amphibious vehicle were conducted at several speeds to investigate the hydrodynamic phenomena using Computational Fluid Dynamics (CFD, RANS code) which is applied by Ansys-CFX14.0 and Maxsurf. The vehicle’s hydrodynamic bow shapes were able to break up induced waves and avoid swamping. Comparative results with the vehicle fitted with U-shape, V-shape and Flat-shape of hull bow, showed that the U-shape of the hull bow has reduced the total resistance to 20.3% and 13.6% compared with the V-shape and flat shape respectively. Though, the U-shape of hull bow is capable to increase the amphibious operating life and speed of vehicle in calm water. Also it has ability to reduce the vehicle’s required power, fossil fuel consumption and wetted hull surfac

First record of the dynamics of domoic acid producing Pseudo-nitzschia spp. in Indonesian waters as a function of environmental variability

Within the past few decades, harmful algal blooms (HABs) have occurred frequently in Indonesian waters, resulting in environmental degradation, economic loss and human health problems. So far, HAB related studies mainly addressed ecological traits and species distribution, yet toxin measurements were virtually absent for Indonesian waters. The aim of the present study was to explore variability of the potentially toxic marine diatom genus Pseudo-nitzschia, as well as its neurotoxin domoic acid as a function of environmental conditions in Ambon Bay, eastern Indonesia. Weekly phytoplankton samples, oceanographic (CTD, nutrients) and meteorological (precipitation, wind) parameters were analyzed at 5 stations in the bay during the dry and wet seasons of 2018. Liquid chromatography – tandem mass spectrometry (LC–MS/MS) was used to detect particulate DA (pDA). Vegetative cells of Pseudo-nitzschia spp. and pDA were found in 98.6% and 51.4% of the samples, respectively. pDA levels were low, yet detected throughout the campaign, implying that Ambon Bay might potentially be subject to amnesic shellfish poisoning. The highest levels of both Pseudo-nitzschia spp. cell abundance and pDA were found in the wet season, showing a strong positive correlation between both parameters, compared to the dry season, (r = 0.87 and r = 0.66 (p < 0.01), respectively). Statistical analyses revealed that temperature and mixed layer depth positively correlated with Pseudo-nitzschia spp. and pDA during the dry season, while ammonium showed positive correlations in both seasons. This study represents the first successful investigation of the presence and variability of Pseudo-nitzschia spp. and its neurotoxin DA in Indonesian waters

The first complete mitochondrial genome data of hippocampus kuda originating from Malaysia

The spotted seahorse, Hippocampus kuda population is exponentially decreasing globally due to habitat loss contributed by massive coastal urbanization as well as its large exploitation for Chinese herbal medicine. Genomic data would be highly useful to improve biomonitoring of seahorse populations in Malaysia via the usage of non-invasive approaches such as water environmental DNA. Here we report the first complete mitogenome of two H. kuda individuals originating from Malaysia, generated using BGISEQ-500RS sequencer. The lengths of both mitogenomes are 16,529bp, consisting of 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and a control region. The overall base composition was 32.46% for A, 29.40% for T, 14.73% for G and 23.41% for C with AT rich features (61.86%). The gene organization of Malaysian H. kuda were similar to that of most teleost species. A phylogenetic analysis of the genome against mtDNA data from other Hippocampus species showed that Malaysian H. kuda samples clustered with H. capensis, H. reidi and H. kuda. Notably however, analysis of the data using BLASTn revealed they had 99.18% similarity to H. capensis, and only 97.66% to H. kuda and H. reidi, which are all part of the unresolved H. kuda complex. The mitogenomes are deposited in Genbank under the accession number MT221436 (HK1) and MT221436 (HK2)

Combustion study of waste cooking oil biodiesel in an oil burner

Depletion of fossil fuels, concerns on environment, and fuel price fluctuation have become the major drives in searching for sustainable alternative fuel. In that regard, a study was conducted to evaluate the combustion performance of Waste Cooking Oil (WCO) converted into biodiesel and blended with Conventional Diesel Fuel (CDF) as a mean of sustainable replacement for diesel fuel. In this study, the production of biodiesel fuel from waste cooking oil was done via transesterification process, using the single step approach. The properties of the WCO biodiesel was characterized. The combustion performance of the produced fuels has been studied for B10 and B30 biodiesel from WCO and CDF (as baseline) based on their wall temperature profiles and gaseous emissions generated such as nitrogen oxides (NOx), carbon monoxide (CO) and sulphur dioxide (SO2). It was found that the B30 WCO biodiesel emits lower emission compared to CDF but at the same time generates a lower temperature profile

Design and analysis of a microstrip patch antenna at 7.5 GHz for X-band VSAT application

In this paper, a microstrip patch antenna is designed to be used for X-band VSAT application at 7.5 GHz. The antenna is proposed to replace the massive and commonly used parabolic reflector antennas (46.0 inch × 29.3 inch × 13.5 inch (116.84 cm × 74.42 cm × 34.29 cm) with weight of 66.2 kg) in terms of portability due to its compact and lightweight features, with overall dimensions of 19.00 mm × 30.55 mm. The 7.5 GHz frequency is chosen based on the X-band frequency used in Malaysia, as reported by STRIDE. The microstrip patch antenna is first designed and simulated using CST Microwave Studio (CST MWS) and exhibits a good return loss (S11) of -42.09 dB, a bandwidth of 399 MHz, directivity of 7.63 dB and gain of 7.18 dB. The antenna is then fabricated using RT/duroid ® High Frequency 5880 substrate with a dielectric constant of εr = 2.2, loss tangent of δ = 0.0009 and thickness of t = 1.574 mm. Next, the return loss and radiation pattern measurements are carried out to confirm the simulated results. The measurement of the antenna prototype provides a return loss S11 of -30.53 dB, bandwidth of 455 MHz, directivity of 5.51 dB and gain of 3.88 dB