117,565 research outputs found
A spatially explicit capture-recapture estimator for single-catch traps
No full textThis work was part-funded by EPSRC grant EP/I000917/1.1. Single-catch traps are frequently used in live-trapping studies of small mammals. Thus far a likelihood for single-catch traps has proven elusive and usually the likelihood for multi-catch traps is used for spatially explicit capture-recapture (SECR) analyses of such data. Previous work found the multi-catch likelihood to provide a robust estimator of average density. 2. We build on a recently developed continuous-time model for SECR to derive a likelihood for single-catch traps. We use this to develop an estimator based on observed capture times and compare its performance by simulation to that of the multi-catch estimator for various scenarios with non-constant density surfaces. 3. While the multi-catch estimator is found to be a surprisingly robust estimator of average density, its performance deteriorates with high trap saturation and increasing density gradients. Moreover, it is found to be a poor estimator of the height (but not range) of the detection function. By contrast, the single catch estimators of density, distribution and detection function parameters are found to be unbiased or nearly unbiased in all scenarios considered. This gain comes at the cost of higher variance, so that despite the lower bias of the single-catch estimator of the density surface over space, its root mean squared error is similar to that of the multi-catch estimator. 4. If there is no interest in interpreting the detection function parameters themselves, and if density is expected to be fairly constantover the survey region, then the multi-catch estimator performs well with single-catch traps. However if accurate estimation of the detection function is of interest, or if density is expected to vary substantially in space, then there is merit in using the single-catch estimator when trap saturation is above about 60%. The estimator’s performance is improved if care is taken to place traps so as to span the range of variables that affect animal distribution. As a single-catch likelihood with unknown capture times remains intractable for now, researchers using single-catch traps should aim to incorporate timing devices with their traps.Peer reviewe
Diagnostic of Water Purity by Using Solar Distiller
No full textIn Present research ,the validity of a solar distiller which is made of two parts ( a solar tank and a solar distiller ) has been tested and distillered the water of one water- trench in Baghdad was treated using this equipment which produced pure water with an average of ( 1106 ml/m2 .h) during the day and (222 ml/m2 .h ) at night .The total water produced is thus ( 1324 ml/m2 . h ) . The laboratorial tests of the samples water before distillation showed that the stream water contained T.P.C/ 1ml =2900 ( Total Content Of Bacteria ) , T.C/100ml >1600 T.C (Total coli form) , F.C /100 ml>1600 (Fecal Coli Formand ) and E. coli /100ml>1600 . The total percentage of salt in water trench before distillation was T.D.S mg/l 1886 \ After water treatment and distillation , the Total Content of Bacteria ( T.P.C) was decreased to T.P.C / 1ml = 210 , (Total coli form) T.C /100 ml = Zero , ( Fecal Coli Formand) F.C/100ml= Zero and E.coli /100ml = Zero . In and, the total percentage of salt after distillation T.D.S was decreased to 105 mg/l . The results of this research show that water distillation using solar distiller is a successful and efficient process led to decreasing T.C.P 93.8% and killing all types of harmful T.C , F.C. and E. coli bacteria. )By analyzing the samples of sterile water using the solar distiller in the laboratories of the Ministry of Health and Environment- Central Environmental Laboratory as shown in Table (6))
RANCANG BANGUN ALAT PEMBUATAN AQUADES DAN AQUABIDES DENGAN METODE PENGUAPAN (TinjauanKinerjaWater Distiller)
No full textKebutuhan aquades di sejumlah sektor akademik maupun non akademik seperti medis dan farmasi di Kota Palembang terbilang besar. Hal itu disebabkan oleh banyaknya kegunaan aquades dalam praktiknya di sektor-sektor tersebut. Akan tetapi, kebutuhan akan bahan pelarut utama itu tidak didukung dengan pengadaan yang sama oleh penyedia. Inilah yang mendorong peneliti untuk melakukan penelitian pembuatan aquades dengan mengolah air kran menggunakan kombinasi proses filtrasi bertahap dan penguapan. Air kran dialirkan ke mikrofilter berpori 0,3 μm dan 0,1 μm kemudian diteruskan ke ultrafilter berukuran pori 0,01 μm. Setelah melalui proses tersebut, air ditampung di dalam tangki berkapasitas ± 100 L yang selanjutnya akan diumpankan ke water distiller sebagai unit penguapan. Kinerja dari water distiller dapat ditinjau melalui perhitungan efisiensi. Tujuan dari penelitian ini adalah untuk mengetahui pengaruh laju alir umpan ke water distiller terhadap laju kenaikan suhu yang optimal bagi proses pemanasan, pendidihan, dan penguapan yang terjadi dalam unit tersebut serta untuk mengetahui pengaruh lama waktu operasi terhadap jumlah bentukan produk atau volume aquades yang dihasilkan. Variasi laju alir umpan diukur secara manual yaitu berdasarkan putaran katup inlet water distiller. Laju alir umpan yang aman dan tidak mengganggu jalannya proses yang terjadi di dalam water distiller adalah sebesar 0,0255 L/menit dengan laju kenaikan suhu yang dipengaruhinya sebesar 0,8 ℃/detik. Dengan laju alir umpan tersebut, maka peneliti mengoperasikan water distiller dan mengamati lama waktu operasi 5, 10, 15, 20, dan 25 menit yang mempengaruhi banyaknya hasil aquades yang didapatkan
Design and construction of a fresnel linear distiller
No full textIt was designed a Fresnel linear distiller based on optical calculations obtained from taking into account Lima’s latitude value, Earth inclination angle and heat absorber cavity’s dimensions. The 5.6 m2 reflective surface concentrator of the distiller was constructed with 32 plane rectangular mirrors; the heat absorber cavity was made with a rectangular blackened aluminum tube 1 m long and installed 2.5 m over the plane of mirrors. The Fresnel linear distiller was installed at the University of Lima and experimental tests were performed during no cloudy summer days. There were measured ambient temperature, heat absorber cavity temperature, radiant flux and fresh water volume. From this, it was obtained a production of 0.89 liters/hour and 0.79 L/m2, and it was calculated a total performance of 34.5% in desalting sea water. Finally, it is presented a comparison between Fresnel linear distiller (FLD) and parabolic trough distiller (PTD) with similar dimensions and characteristics. It is obtained that the last one produced almost 32% more fresh water than the former, but at the same time, the FLD is almost 20% cheaper than PTD. However, water cost production with both distillers using is almost the same
Hemispherical Solar Distiller Performance Utilizing Hybrid Storage Media, Paraffin Wax with Nanoparticles: An Experimental Study
No full textThe traditional method of obtaining fresh water for drinking is by burning fossil fuels, emitting greenhouse gases into the atmosphere. However, renewable energy is gaining more traction since it is available free of cost for producing fresh water. In this study, Al2O3 nanoparticles were distributed in a phase change material (paraffin wax) that had been fixed at a hemispherical distiller water basin. Three scenarios with three hemispherical distillers were examined. A conventional hemispherical distiller (CHD), a conventional hemispherical distiller with paraffin wax as a phase change material (CHD-PCM), and a conventional hemispherical distiller with PCM partially filled with Al2O3 nanoparticles (CHD-N-PCM) were tested under the same climatic conditions. The experimental results showed that CHD gave a daily yield of 4.85 L/m2/day, while CHD-PCM increased the yield to up to 6.2 L/m2/day with a 27.84% daily yield enhancement. The addition of Al2O3 nanoparticles to paraffin wax CHD-N-PCM improved hemispherical distillate yield up to 8.3 L/m2/day with a 71.13% increase over CHD yield
Modelling distillate output of a solar distiller with eco-friendly wood-based steam generation basin using machine learning model and starling murmuration optimizer
No full textYield augmentation of solar distiller (SD) using low-cost modifications with minimum environmental impacts is highly desirable. In this study, we developed an eco-friendly steam generation device made of carbonized Ficus sycomorus wood to boost the yield of the conventional single-basin solar distiller. Moreover, a hybrid model composed of a long short-term memory (LSTM) network and a Starling murmuration optimizer (SMO) was developed to predict the yield of the established SD. To verify the accuracy of the model, three other models were employed and the distillate yield was predicted. The predicted data of all models was evaluated using different error measures. These models were standalone LSTM and LSTM optimized by an artificial hummingbird algorithm (AHA) or manta ray foraging optimizer (MRFO). Real field data were employed during the training and testing of all models. The thermal performance of the distiller with the steam generation device was compared with that of a traditional distiller based on exergy output, exergy efficiency, and energy efficiency. The distillate yield, exergy efficiency, and energy efficiency of the modified SD were enhanced by 34 %, 49 %, and 40 %, respectively, compared with that of the traditional distiller. Moreover, the total amount of produced drinkable water using the modified SD could reach a high value of 6.1 L/day with a low cost of 0.014 $/L
Design, Construction and Performance Evaluation of a Small Scale Biofuel Distiller
No full textA biofuel distiller of 20 L feed capacity was designed fabricated and used to distill bioethanol from a biomass broth. The distiller consists of a 40 L volume boiler unit integrated to the combustion chamber as a cylindrical column; and a counter current cylindrical condenser of length, tube and shell internal diameter of 88 cm, 0.0191/0.15 m, inclined at 450. The reactor is a Top Lit Updraft (T-LUD) type fired with charcoal of moderate lump. Its performance evaluation was conducted using 20 L palm bunch broth as the distiller feed. The palm bunch collected from Siat Nigeria Ltd, Ubima, Rivers State, Nigeria, was physically pretreated by grinding to powder, hydrolyzed with 1.2 % dilute H2SO4, at 160°C for 30 min and fermented for 72 h with S.cerevisiae separated from palm wine. The broth was then separated from the slurry by filtering before distillation. The result of the machine evaluation showed that 817 ml bioethanol was obtained per batch at 20 min from the bubble point which took 95 min. Actual combustion efficiency was found to be 55 % with reactor power rating of 12.2 kW. The machine vaporized bioethanol fuel from the boiler feed fed at 27°C, and released the distillate at 28.3°C. Distillation efficiency was found to be greater than 90 % while the maximum productivity occurred at 10 min from the bubble point. The machine is economical, reliable, convenient to use and can stand diverse environmental conditions. It can be integrated as a waste management step in the downstream end of palm mill operations
SOLAR DISTILLER IN A PYRAMIDAL COVERING AND ISOLATION WITH COMPOSITE MATERIAL
No full textTo demonstrate the thermal calorific and economic viability of the material, compared to the others conventional distiller, here is presented a solar distiller of simple stage, witch has as main differential characteristics the geometry of the covering and the material used to make its coating. The model built has an area of 0.25 m² and pyramidal covering, witch allows the collection of the distillate water in the four faces, different of just two like is found in the conventional distiller, besides promote the absorption of the radiation because of its versatility about the positioning of the sun. Not despite, its built is favored for the low cost associated and the agility in the process because it is made with a mix of gypsum, EPS ground and water, witch also attributes to the distiller thermal properties more favorable to the process of distillation
Comparative Study of Experimental and Theoretical Convective, Evaporative for Two Model Distiller
No full textThe purification of brackish seawater becomes a necessity and not a choice against demographic and industrial growth especially in third world countries. Two models can be used in this work: simple solar still and simple solar still coupled with a heat pump. In this research, the productivity of water by Simple Solar Distiller (SSD) and Simple Solar Distiller Hybrid Heat Pump (SSDHP) was determined by the orientation, the use of heat pump, the simple or double glass cover. The productivity can exceed 1.2 L/m²h for the SSDHP and 0.5 L/m²h for SSD model. The result of the global efficiency is determined for two models SSD and SSDHP give respectively 30%, 50%. The internal efficiency attained 35% for SSD and 60% of the SSDHP models. Convective heat coefficient can be determined by attained 2.5 W/m²°C and 0.5 W/m²°C respectively for SSDHP and SSD models
Evaluation of a Solar Water Distiller Coupled with Solar Evacuated Tubes
No full textThe scarcity of fresh water is a primary problem in remote regions. Thus, an economical and related water distillation solar still coupled with a solar collector was designed and studied experimentally. This study aims to investigate and evaluate the performance of an active single-slope solar still (ASSSS) coupled with a solar evacuated tube collector (ETC) as the water heater. The results showed that the average distillate productivity of ASSSS combined with U pipe solar (ETC) was 1.085 l/m2 in December 2020, but 3.12 l/m2 in August 2021. These quantities of the water distiller were higher than those of a passive solar distiller with a single slope (PSSSS). The average value of the water temperature increased using the ASSSS coupled with ETC in August 2021 at 79.1°C, whereas it was 71°C in August 2021 for PSSSS. These results indicate that the ASSSS is more effective than the PSSSS
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