2,528 research outputs found

    Pengaruh Hydraulic Retention TIME (Hrt) Dan Konsentrasi Influen Terhadap Penyisihan Parameter Bod Dan Cod Pada Pengolahan Limbah Domestik Greywater Artificial Menggunakan Reaktor Uasb

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    In urban areas domestic wastewater pollution reaches 60 % and about 75 % of the total volume of domestic wastewater is greywater . As an alternative wastewater treatment, UASB ( Upflow Anaerobic Sludge Blanket ) is an effective waste processing because it has many advantages . Several factors affect the performance of UASB reactors is Hydraulic Retention Time ( HRT ) and influent concentration. In the COD removal and BOD , reactors with HRT 4 hours having the smallest removal efficiency , i.e. by 36 % and 20 % . Reactor reaches the optimum point processing when operated at HRT 12 hours , where COD removal efficiency of 73% and BOD removal efficiency of 66% . In the reactor with medium concentration range ( S ) with an influent COD of 760 - 880mg / L of COD and BOD removal efficiency reached a maximum of 77 % and 75 % . While the smallest efficiency reactor obtained at low concentrations ( R ) with the organic content of the feed ( influent ) of 133-160 mg / L with a COD removal efficiency of 48% and BOD by 44 %

    The Cerebellar Fastigial Nucleus Contributes to CO\u3csub\u3e2\u3c/sub\u3e-H\u3csup\u3e+\u3c/sup\u3e Ventilatory Sensitivity in Awake Goats

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    The purpose of this study was to test the hypothesis that an intact cerebellar fastigial nucleus (CFN) is an important determinant of CO2-H+ sensitivity during wakefulness. Bilateral, stainless steel microtubules were implanted into the CFN (N = 9) for injection (0.5–10 ÎŒl) of the neurotoxin ibotenic acid. Two or more weeks after implantation of the microtubules, eupneic breathing and CO2-H+ sensitivity did not differ significantly (P \u3e 0.10) from pre-implantation conditions. Injection of ibotenic acid (50 mM) did not significantly alter eupneic PaCO2 (P \u3e 0.10). The coefficient of variation of eupneic PaCO2 was 4.0 ± 0.6 and 3.7 ± 0.4% over the 2 weeks before and after the lesion, respectively. CO2-H+ sensitivity expressed as inspired ventilation/PaCO2 decreased from 2.15 ± 0.17 pre-lesion to 1.58 ± 0.26 l/(min mmHg) 3–6 days post-lesion (P \u3c 0.02, −27%). There was no significant (P \u3e 0.10) recovery of sensitivity between 7 and 10 days post-lesion. The lesion also increased (P \u3c 0.05) the day-to-day variability of this index by nearly 100%. When CO2 sensitivity was expressed as elevated inspired CO2/room air VI, values at 7%, but not 3 and 5% inspired CO2, were reduced and more variable (P \u3c 0.05) after the ibotenic acid injections. We conclude that during wakefulness, the CFN contributes relatively more to overall ventilatory drive at high relative to low levels of hypercapnia

    Ultrasensitive Displacement Noise Measurement of Carbon Nanotube Mechanical Resonators

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    Mechanical resonators based on a single carbon nanotube are exceptional sensors of mass and force. The force sensitivity in these ultra-light resonators is often limited by the noise in the detection of the vibrations. Here, we report on an ultra-sensitive scheme based on a RLC resonator and a low-temperature amplifier to detect nanotube vibrations. We also show a new fabrication process of electromechanical nanotube resonators to reduce the separation between the suspended nanotube and the gate electrode down to ∌150\sim 150~nm. These advances in detection and fabrication allow us to reach 0.5 pm/Hz0.5~\mathrm{pm}/\sqrt{\mathrm{Hz}} displacement sensitivity. Thermal vibrations cooled cryogenically at 300~mK are detected with a signal-to-noise ratio as high as 17~dB. We demonstrate 4.3 zN/Hz4.3~\mathrm{zN}/\sqrt{\mathrm{Hz}} force sensitivity, which is the best force sensitivity achieved thus far with a mechanical resonator. Our work is an important step towards imaging individual nuclear spins and studying the coupling between mechanical vibrations and electrons in different quantum electron transport regimes.Comment: 9 pages, 5 figure

    The Effects of Lesions in the Dorsolateral Pons on the Coordination of Swallowing and Breathing in Awake Goats

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    The purpose of this retrospective study was to gain insight into the contribution of the dorsolateral pons to the coordination of swallowing and breathing in awake goats. In 4 goats, cannulas were chronically implanted bilaterally through the lateral (LPBN) and medial (MPBN) parabrachial nuclei just dorsal to the Kölliker–Fuse nucleus (KFN). After \u3e2 weeks recovery from this surgery, the goats were studied for 5Âœ h on a control day, and on separate days after receiving 1 and 10 ÎŒl injections of ibotenic acid (IA) separated by 1 week. The frequency of swallows did not change during the control and 1 ÎŒl IA studies, but after injection of 10 ÎŒl IA, there was a transient 65% increase in frequency of swallows (P \u3c 0.05). Under control conditions swallows occurred throughout the respiratory cycle, where late-E swallows accounted for 67.6% of swallows. The distribution of swallow occurrence throughout the respiratory cycle was unaffected by IA injections. Consistent with the concept that swallowing is dominant over breathing, we found that swallows increased inspiratory (TI) and expiratory (TE) time and decreased tidal volume (VT) of the breath of the swallow (n) and/or the subsequent (n + 1) breath. Injections of 10 ÎŒl IA attenuated the normal increases in TI and TE and further attenuated VT of the n breath. Additionally, E and I swallows reset respiratory rhythm, but injection of 1 or 10 ÎŒl IA progressively attenuated this resetting, suggesting a decreased dominance over respiratory motor output with increasing IA injections. Post mortem histological analysis revealed about 50% fewer (P \u3c 0.05) neurons remained in the KFN, LPBN, and MPBN in lesioned compared to control goats. We conclude that dorsolateral pontine nuclei have a modulatory role in a hypothesized holarchical neural network regulating swallowing and breathing particularly contributing to the normal dominance of swallowing over breathing in both rhythm and motor pattern generation

    High performance bilayer-graphene Terahertz detectors

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    We report bilayer-graphene field effect transistors operating as THz broadband photodetectors based on plasma-waves excitation. By employing wide-gate geometries or buried gate configurations, we achieve a responsivity ∌1.2V/W(1.3mA/W)\sim 1.2V/W (1.3 mA/W) and a noise equivalent power ∌2×10−9W/Hz−1/2\sim 2\times 10^{-9} W/Hz^{-1/2} in the 0.29-0.38 THz range, in photovoltage and photocurrent mode. The potential of this technology for scalability to higher frequencies and the development of flexible devices makes our approach competitive for a future generation of THz detection systems.Comment: 8 pages, 5 figures. Submitted to Applied Physics Letter

    Superselectors: Efficient Constructions and Applications

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    We introduce a new combinatorial structure: the superselector. We show that superselectors subsume several important combinatorial structures used in the past few years to solve problems in group testing, compressed sensing, multi-channel conflict resolution and data security. We prove close upper and lower bounds on the size of superselectors and we provide efficient algorithms for their constructions. Albeit our bounds are very general, when they are instantiated on the combinatorial structures that are particular cases of superselectors (e.g., (p,k,n)-selectors, (d,\ell)-list-disjunct matrices, MUT_k(r)-families, FUT(k, a)-families, etc.) they match the best known bounds in terms of size of the structures (the relevant parameter in the applications). For appropriate values of parameters, our results also provide the first efficient deterministic algorithms for the construction of such structures

    Umbilical Cord Knots: Is the Number Related to Fetal Risk?

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    True knots of the umbilical cord (UC) are a rare occurrence and are reported in 0.4–1.2% of deliveries. The compression of true knot of the UC can cause obstruction of the fetal circulation, leading to intra‐uterine growth retardation or fetal death. Predisposing factors for the genesis of the true UC knot are numerous and include all the conditions, which lead to a relatively large uterine volume. This situation may predispose to free and excessive fetal movements. Although not all true knots lead to perinatal complications, they have been associated with adverse pregnancy outcomes, including fetal distress, fetal hypoxia, intra‐uterine growth restriction (IUGR), long‐term neurological damage, caesarean delivery and stillbirth. We present a rare case of operative delivery with vacuum in a multiparous woman at term of pregnancy with a double true knot of the UC. As in most cases, the diagnosis was made after delivery, as there were no fetal symptoms during pregnancy. Some authors assume that 3D power sonography may be useful in the diagnosis of true UC knots. However, 3D power Doppler cannot be considered as a definitive method. There are no specific prenatal indications to induce the physician to look for ultrasound signs suggestive of umbilical true knot. Some studies argue that cases of fetal death and fetal risk are directly related to the number of knots. We also support this thesis, even if further observational and retrospective studies are needed to demonstrate it
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