Effect of Leachate Circulation on Biogas Production from Market Waste and Rice Straw

The production of biogas from animal waste has been studied and technologies are beingused for the management of animal wastes as well as for the generation of renewable energy.The organic fraction of the market garbage as well as agricultural wastes (organic fraction)can properly be affected for the biogas production through proper physiochemical treatmentsof raw materials.In this study it was attempted to find out the effect of leachate circulation on biogasproduction from reactors fed with organic fraction of market waste (MW) and rice straw(RS).The laboratory reactor model (20 L) was fabricated using plastic cans. The provisions atthe bottom and top of the reactor were made to circulate the leachate produced duringanaerobic digestion. The leachate circulation was performed using a peristaltic pump. Thereactor was fed with MW & RS (< 1mm particle size) in the ratio of 1:3. The total rawmaterials fed to the digester were 3 kg (dry matter) and total solid level was adjusted to 20%by adding water. Before starting the experiment inoculums (digested material from a biogasdigester running biogas) was added. The experiment was conducted ~ 3 months under once aday circulation. Biogas production, temperature and pressure were measured daily. pH &Chemical Oxygen Demand of leachate were determined once a week. At the middle of theexperiment CH4 was also determined. The C: N ratio of the mixture of raw materials fed forthe study was ~25:1. The consistence biogas production was noted after one week of start ofstudy. Biogas production rate was gradually increased up to ~45 days and it was decreased atthe end of three months period. The total biogas production was ~36 m3/kg and its methanecontent was ~50%. At the beginning of the study pH was neutral and it was reduced to ~4during 6 weeks. Then it has gradually increased due to produced volatile fatty acid bymethanogenic bacteria. COD determined in leachate during the study period graduallydecreased with the increased biogas production. It was concluded that the biogas productionwith leachate circulation was very high than without leachate circulation based on theprevious trials.

Electron Cloud Measurements in Fermilab Booster

Fermilab Booster synchrotron requires an intensity upgrade from 4.5x1012 to 6.5x1012 protons per pulse as a part of Fermilab's Proton Improvement Plan-II (PIP-II). One of the factors which may limit the high-intensity performance is the fast transverse instabilities caused by electron cloud effects. According to the experience in the Recycler, the electron cloud gradually builds up over multiple turns inside the combined function magnets and can reach final intensities orders of magnitude greater than in a pure dipole. Since the Booster synchrotron also incorporates combined function magnets, it is important to measure the presence of electron cloud. The presence or apparent absence of the electron cloud was investigated using two different methods: measuring bunch-by-bunch tune shift by changing the bunch train structure at different intensities and propagating a microwave carrier signal through the beampipe and analyzing the phase modulation of the signal. This paper presents the results of the two methods and corresponding simulation results conducted using PyECLOUD software.Comment: International Particle Accelerator Conference 202

Online Job Search: A Study on Optimizing Online Platforms to Facilitate Effective Job Search

Technological advancement along with the expanding number of users and internet-based businesses have created a worldwide market for both job recruiters and job seekers. This has drastically changed areas of job searching and job recruiting. Traditional methods of recruiting and job hunting have been obsoleting since the introduction of digitalized platforms to perform these tasks, leading to better results when matching the intents of job recruiters to job seekers. There are numerous online job search platforms but everyone one of them contains some major issues. We have examined the related studies and identified that these issues exist in the areas of screening job applications, optimizing job search queries, and demographic inequity in candidate selection. Although these topics have been researched independently, there is a lack of implementational solutions available to address all these issues together. As a result of our study on this deficiency, we have come up with a practical solution implemented as a web application addressing these issues and providing job seekers and job recruiters with an online platform with enhanced accuracy and user experience

Species Composition and Diversity in two Selected Lowland Tropical Rainforests in Sri Lanka and their Relationships to Temperature and Precipitation

Tropical rainforests are characterised by high species diversity, which may be due to a range of factors such as climate, topography, soil properties and the level of disturbance, both natural and anthropogenic. This study focused on investigating the species composition, richness, diversity and their conservation status in lowland tropical rainforests at two selected locations in Sri Lanka and determining their relationships to temperature and precipitation. Two permanent one-hectare sampling plots each were established at the Kanneliya (KDN1 and KDN2) and Pitadeniya-Sinharaja (PTD1 and PTD2) Forest Reserves. All trees with dbh≥10 cm were enumerated. A total of 3,303 trees were recorded, representing 158 species from 91 genera and 53 families, with a total basal area of 196.26 m2. Most abundant plant species were Alstonia macrophylla in KDN1 (11.7% of trees with dbh≥10 cm), Syzygium grande in KDN2 (9.8%), Shorea affinis in PTD1 (15.8%) Mesua thwaitesii in PTD2 (17.5%). Cullenia rosayroana (7.2%) is the most abundant species within the whole study area. While 25 species were recorded in all four plots, 70 species were found in only one location. Genus Shorea (18.6%) is the most common including 12 different species and Dipterocarpaceae (21.9%) is the most common family including 19 species. KDN1 recorded 1,011 plants from 108 species, with 74.3% endemic, 12.8% native and 11.9% exotic species. Other study sites recorded only endemic (88% at KDN2, 83.7% at PTD1 and 82.3% at PTD2) and native species. In comparison to PTD, KDN recorded higher numbers of trees with dbh≥10 cm (Chi-square p<0.0001), species (p<0.0001) and genera (p=0.0091). KDN also recorded a higher number of families but the difference was not significant (p=0.358). All indices of species diversity (Shannon index, H and Simpson index, D), evenness (J) and richness (R) are higher at KDN. However, only the difference in D was statistically-significant at p=0.05. Multiple regression analysis using the stepwise procedure showed that the number of trees with dbh≥10 cm and the species number increased with increasing average annual air temperature (T) but decreased with annual total precipitation (P). On the other hand, the numbers of genera and families increased with decreasing P with T not having a significant influence. The two diversity indices, H and D, increased with decreasing P and increasing T. In contrast, increasing P decreased J and R whereas variation in T did not have a significant influence. These findings provide important insights in to dynamics plant diversity in response to environmental changes.Keywords: Species composition, Species diversity, Tropical rainforest

New Simulations for Ion-Production and Back-Bombardment in GaAs Photo-guns

GaAs-based DC high voltage photo-guns used at accelerators with extensive user programs must exhibit long photocathode operating lifetime. Achieving this goal represents a significant challenge for proposed high average current facilities that must operate at tens of milliamperes or more. Specifically, the operating lifetime is dominated by ion back-bombardment of the photocathode from ionized residual gas. While numerous experiments have been performed to characterize the operating lifetime under various conditions, detailed simulations of the ion back-bombardment mechanism that explains these experiments are lacking. Recently, a new user routine was implemented using the code General Particle Tracer (GPT) to simulate electron impact ionization of residual beam line gas and simultaneously track the incident electron, the ejected electron, and the newly formed ion. This new routine was benchmarked against analytical calculations and then applied to experiments performed at the CEBAF injector at the Thomas Jefferson National Accelerator Facility to study the effectiveness of limiting ions from entering the cathode-anode gap using a positively biased anode. These simulations were performed using detailed 3D field maps produced with CST Microwave Studio describing the photo-gun electrostatics. Discussion of the experiment and the application of this new GPT routine to model the experiments will be presented at the workshop

Simulation Study of the Magnetized Electron Beam

Electron cooling of the ion beam plays an important role in electron ion colliders to obtain the required high luminosity. This cooling efficiency can be enhanced by using a magnetized electron beam, where the cooling process occurs inside a solenoid field. This paper compares the predictions of ASTRA and GPT simulations to measurements made using a DC high voltage photogun producing magnetized electron beam, related to beam size and rotation angles as a function of the photogun magnetizing solenoid and other parameters

Space Charge Study of the Jefferson Lab Magnetized Electron Beam

Magnetized electron cooling could result in high luminosity at the proposed Jefferson Lab Electron-Ion Collider (JLEIC). In order to increase the cooling efficiency, a bunched electron beam with high bunch charge and high repetition rate is required. We generated magnetized electron beams with high bunch charge using a new compact DC high voltage photo-gun biased at -300 kV with alkali-antimonide photocathode and a commercial ultrafast laser. This contribution explores how magnetization affects space charge dominated beams as a function of magnetic field strength, gun high voltage, laser pulse width, and laser spot size

Thermal Emittance and Lifetime of Alkali-Antimonide Photocathodes Grown On GaAs and Molybdenum Substrates Evaluated in a -300 kV dc Photogun

CsxKySb photocathodes grown on GaAs and molybdenum substrates were evaluated using a –300 kV dc high voltage photogun and diagnostic beam line. Photocathodes grown on GaAs substrates, with varying antimony layer thickness (estimated range from \u3c 20 nm to \u3e 1 um), yielded similar thermal emittance per rms laser spot size values (~0.4 mm mrad / mm) but very different operating lifetime. Similar thermal emittance was obtained for a photocathode grown on a molybdenum substrate but with markedly improved lifetime. For this photocathode, no decay in quantum efficiency was measured at 4.5 mA average current and with peak current 0.55 A at the photocathode

Simulation Study of the Emittance Measurements in Magnetized Electron Beam

Electron cooling of the ion beam is key to obtaining the required high luminosity of proposed electron-ion colliders. For the Jefferson Lab Electron Ion Collider, the expected luminosity of 10³⁴ 〖 cm〗⁻² s⁻¹ will be achieved through so-called ’magnetized electron cooling’, where the cooling process occurs inside a solenoid field, which will be part of the collider ring and facilitated using a circulator ring and Energy Recovery Linac (ERL). As an initial step, we generated magnetized electron beam using a new compact DC high voltage photogun biased at -300 kV employing an alkali-antimonide photocathode. This contribution presents the characterization of the magnetized electron beam (emittance variations with the magnetic field strength for different laser spot sizes) and a comparison to GPT simulations

Generation and Characterization of Magnetized Electron Beam From a DC High Voltage Photogun for Electron Beam Cooling Application

One of the most challenging requirements for the proposed Electron–Ion Collider is the strong cooling of the proton beam, which is key to achieving the collider’s desired luminosity of order 1033–1034cm−2s−1. Magnetized bunched-beam electron cooling could be a means to achieve the required high luminosity, where strong cooling is accomplished inside a cooling solenoid where the ions co-propagate with an electron beam generated from a source immersed in a magnetic field. To increase the cooling efficiency, a bunched electron beam with high bunch charge and high repetition rate is required. This work describes the production and characterization of magnetized electron beam using a compact 300 kV DC high voltage photogun and bi-alkali antimonide photocathode. Beam magnetization was studied using a diagnostic beamline that includes viewer screens for measuring the shearing angle of the electron beamlet passing through a narrow upstream slit. Simulations and corresponding measurements of beam magnetization are presented as a function of laser spot size and magnetic field strength. Correlated beam emittance with magnetic field (0–0.15T) at the photocathode was measured for various laser spot sizes. Measurements of photocathode lifetime were carried out at different magnetized electron beam currents up to 28 mA, and bunch charge up to 0.7 nC (not simultaneously)