Analysis of complex ventilation networks in multiple fan coal mines

Coal mines require very effective and proper ventilation systems not only to keep the levels of explosive, harmful gases and dust to a safe level but also to deliver enough fresh air for miners to breathe. Depending upon the size of the mine and the quantity of gases and dust in this mine, it could be ventilated by using a single fan or several fans. There are two types of fans used in mines: vane axial and centrifugal.;In multiple-fan systems, each individual fan influences the performance of the whole system, including the other fans. Each fan in the system has its own mine characteristic curve or subsystem curve. Thus the present of an axial flow fan or fans inside each subsystem turns the resistance factor of the subsystem into a variable. Thus the relationship between the airflow and the pressure consumed through the subsystem does not strictly follow Atkinson equation. The shape of the subsystem curve and the number of the operating points in the system depend on the number and type of fans inside the subsystem. The shape of this subsystem characteristic curve could have sharp turning points and its shape may not be fixed as in the single fan system.;Both the implemented Hardy Cross method and damped Newton-Raphson method using switching parameters are found to be good tools to trace these subsystem characteristic curves. The modified Hardy Cross method is faster and more flexible than the modified damped Newton-Raphson method, especially when solving large networks

Dosimetric Efficacy of Voluntary Deep Inspiration Breath-Hold in the Radiotherapy of Left Breast Cancer Patients Using the UK START Trial

Introduction: Deep inspiration breath-hold (DIBH) technique is widely administered to left breast cancer (LBC) patients to reduce the cardiopulmonary radiation doses. The UK standardization of breast cancer radiotherapy (UK START) dose prescription was found comparable to the conventional schedule. The current study compared voluntary DIBH and free-breathing (FB) methods in the cardiopulmonary radiation doses of LBC patients with supraclavicular irradiation treated with the UK START trial.Material and Methods: Computed tomography (CT) scans were acquired for a group of 50 LBC patients in DIBH and FB and a radiotherapy plan was created on each scan. The dose-volume histogram parameters of the heart and lung were analyzed against their relevant first clinical acceptance criteria using one-sample t-test. Additionally, the correlation between the ipsilateral lung volume expansion and the cardiopulmonary dosimetric benefits was assessed.Results: The cardiopulmonary radiation doses were significantly reduced in DIBH compared with FB. For DIBH, the mean difference between the mean heart dose (MHD), Heart V16Gy, and Lung V16Gy and their first acceptance criteria was -62.6 cGy, -0.63%, and -2.18% (p < 0.001), respectively. In contrast, the first acceptance criteria of the cardiopulmonary dosimetric parameters were not accomplished with the FB method. In addition, the difference in MHD and heart V20Gy between DIBH and FB plans showed a moderate correlation with ipsilateral lung volume expansion (r = 0.51 and 0.5, respectively).Conclusion: DIBH technique should be served to all locally advanced LBC patients, and the ipsilateral lung volume expansion could be a predictor for the cardiac-sparing radiotherapy in LBC

Enhancement of alpha amylase production by Aspergillus flavus AUMC 11685 on mandarin (Citrus reticulata) peel using submerged fermentation

Mandarin peel as submerged fermentation (SmF) source was tested for the production of alpha amylase enzyme by strain of Aspergillus flavus AUMC 11685. Incubation period, concentration of substrate, temperature, pH and size of inoculum were optimized to achieve the maximum production of alpha amylase enzyme by Aspergillus flavus using mandarin peel. The maximum production of alpha amylase enzyme by Aspergillus flavus&nbsp;was recorded at 4-5 days of incubation, 3% substrate concentration, inoculum concentration 10%, temperature 28-40°C and pH 4-5.5. DOI: http://dx.doi.org/10.5281/zenodo.81827

Performance of Radiation Dosimeters in Gradient Regions at Different Dose Rates of Linear Accelerators

Introduction: This work aimed to evaluate the accuracy of using parallel plane against thimble chambers in beam data commissioning of the high dose gradients region for versa HD linear accelerator performing clinical advanced modulated radiation treatment techniques.Material and Methods: All clinical commissioning data were collected from Elekta Versa HD for energies of 6 MV, 10 MV, 6 MV FFF, and 10 MV FFF for different field sizes using thimble ionization chamber CC13, some from the pool of the measured data were rescanned using parallel plate chamber PPC05 and Gafchromic films and compared to those collected using the thimble ionization chamber.Results: The skin doses differences measured by thimble chamber against reference films were (0.8%, 0.5%, 1.2% 4.7%) and for the parallel plane chamber against films were (8.4%, 9.7%, 9%, 12%) for 6 MV, 10 MV, 6 MV FFF, 10 MV FFF, respectively. The parried test-test showed a highly significant difference (p> 0.001) between the two chambers in measurements of penumbra regions taking over all the investigated field sizes and depths in both inline and crossline datasets. The parallel plate showed a wider and broader penumbra than the thimble chamber and films.Conclusion: Robust and consistent scans were obtained for the thimble chamber compared to the parallel plane chamber in the highest dose gradient of buildup and penumbra regions. Using a parallel plane chamber might bring dosimetric clinical uncertainties affecting the modeling of the gradient regions in the treatment planning system

Studies on the Recovery of Cu (II) and U (VI) on Highly Adsorptive Modified Magnetic Amine Resins from Dolostone Leachate Solution

Magnetic chelating resin containing amine moiety was obtained by polymerization of chloromethyl styrene with both 5 % and 10% divinylbenzene as a crosslinking agent in the presence of Fe3O4 as magnetite particles, the yield was treated with malononitrile followed by reaction with hydrazine hydrate in the presence of absolute ethanol to get hydrazenyl amine polymer. The obtained resins were investigated by FT-IR, elemental analysis and SEM. The use of magnetite particles was used for increasing the surface of chelating active sites and easy collection from solution. The obtained resins were evaluated toward the uptake of Cu (II) and U (VI) from their aqueous synthetic solutions followed by application on acid leachate of dolostone ore materials from southwestern Sinai. Contact time, pH and initial concentration of the metal ions were investigated as factors affecting the uptake behavior. The modified resins display higher uptake capacity compared to the metal oxide-free resin also high regenerated efficiency

Proučavanje relativističke tvorbe hadrona prema naprijed i unatrag u sudarima 3he i 4he s jezgrama u emulziji na energiji ubrzivača u dubni

The experimental results on 3He- and 4He-emulsion interactions accompanied by relativistic (shower) hadrons flying into the backward (θlab ≤ 90◦ ) hemisphere at 4.5 AGeV/c are presented and analyzed. The dependence of the probabilities of these interactions on the different target sizes, impact parameter and projectile spectator charges is studied. An investigation of average values and multiplicity distributions of these hadrons for the interactions with light and heavy emulsion nuclei has been carried out. In addition, the correlations between the multiplicities of different types of the emitted particles are studied. The data show that backward shower particles are a sensitive target parameter. The values of impact parameters can be used as good indicators for selecting events which occured with light or heavy emulsion nuclei. A comparison with the modified cascade model shows a good performance in describing the data produced in the region having less cascading (i.e. interactions with light nuclei). As for the interactions with heavy nuclei, the model overestimates the experimental data.Predstavljamo eksperimentalne rezultate i analize mjerenja međudjelovanja 3He i 4He u emulziji na 4.5 AGeV/c, u kojima se opažaju relativistički pljuskovi hadrona koji lete unatrag (θlab ≤ 90◦ ). Proučavamo ovisnost vjerojatnosti tih međudjelovanja o veličini jezgre mete, sudarnom parametru i naboju projektila-promatrača. Istražili smo prosječne vrijednosti i raspodjele višestrukosti hadrona za lake i teške jezgre u emulziji. Nadalje, proučavali smo korelacije višestrukosti različitih izlaznih čestica. Podaci pokazuju da su pljuskovi čestica unatrag osjetljiv parametar jezgri mete. Vrijednosti parametara mogu poslužiti kao dobar pokazatelj sudara s lakim odnosno teškim jezgrama. Usporedba s promijenjenim kaskadnim modelom pokazuje dobro slaganje s podacima u kojima je manje kaskada (tj. Manje sudara s lakim jezgrama). Rezultati tog modela za teške jezgre veći su od eksperimentalnih podataka

Prospects for SIMPLE 2000: A large-mass, low-background Superheated Droplet Detector for WIMP searches

SIMPLE 2000 (Superheated Instrument for Massive ParticLE searches) will consist of an array of eight to sixteen large active mass ($\sim15$ g) Superheated Droplet Detectors(SDDs) to be installed in the new underground laboratory of Rustrel-Pays d'Apt. Several factors make of SDDs an attractive approach for the detection of Weakly Interacting Massive Particles (WIMPs), namely their intrinsic insensitivity to minimum ionizing particles, high fluorine content, low cost and operation near ambient pressure and temperature. We comment here on the fabrication, calibration and already-competitive first limits from SIMPLE prototype SDDs, as well as on the expected immediate increase in sensitivity of the program, which aims at an exposure of $>$25 kg-day during the year 2000. The ability of modest-mass fluorine-rich detectors to explore regions of neutralino parameter space beyond the reach of the most ambitious cryogenic projects is pointed out.Comment: 19 pages, 10 figures included. New Journal of Physics, in pres

First Dark Matter Limits from a Large-Mass, Low-Background Superheated Droplet Detector

We report on the fabrication aspects and calibration of the first large active mass ($\sim15$ g) modules of SIMPLE, a search for particle dark matter using Superheated Droplet Detectors (SDDs). While still limited by the statistical uncertainty of the small data sample on hand, the first weeks of operation in the new underground laboratory of Rustrel-Pays d'Apt already provide a sensitivity to axially-coupled Weakly Interacting Massive Particles (WIMPs) competitive with leading experiments, confirming SDDs as a convenient, low-cost alternative for WIMP detection.Comment: Final version, Phys. Rev. Lett. (in press