Evaluation of brick kiln performances using computational fluid dynamics (CFD)

Modern history of civilization is concurrent to the use of brick and its manufacturing. Nowadays tunnel kiln is the most widely used technology for brick production. This paper tries to provide an idea of the brick making process in tunnel kiln. The computational fluid dynamics (CFD) software, ANSYS CFX is being used to evaluate kiln performances using gas as its fuel. Simplified geometry was drawn and meshed using appropriate tools of ANSYS CFX. Several pertinent assumptions were made to reduce the complication of the simulation. Turbulence, combustion, radiation and NO models were adopted for simulation of a realistic tunnel kiln environment. Simulated temperature profile almost replicates industrial kiln situation as found in existing literature. CFD analysis helps to simulate the temperature profile of the brick kilns, the mass flow fractions of CO2 and NO emissions at outlet, and also the air velocity profile inside the kiln. The simulated temperature generated in a tunnel kiln is found to be between 1300 K and 300 K. CO2 and NOx volume generated inside the kiln is estimated as 1.01 m3/s and 0.108 m3/s respectively

Evaluation of brick kiln performances using computational fluid dynamics (CFD)

Modern history of civilization is concurrent to the use of brick and its manufacturing. Brick kiln is the most important component in the manufacturing of clay-burnt bricks. Poorly operated brick kilns are considered as the major sources of greenhouse gas (GHG) emission nowadays. Various types of brick kilns are in operation throughout the world. Tunnel kiln is the most widely used technology in developed countries as it is highly automated. Other technologies which are quite popular in developing countries are: Hoffman kiln, Vertical Shaft kiln, Fixed Chimney kiln, Zigzag kiln, etc. Computational Fluid Dynamics (CFD) software, ANSYS CFX is being applied to evaluate performance of Tunnel kiln using natural gas as its fuel. The idea of a typical Tunnel kiln layout geometry has been envisaged from local brick industries. The length, width and height of the Tunnel kiln geometry are taken as 100 m × 3.24 m × 1.48 m. The length and width of the brick stack is taken as 920 mm × 440 mm. With a gap of 400 mm and 100 mm between two brick stacks longitudinally and laterally respectively, a total of 450 (6 × 75) stacks can be accommodated inside the kiln at a time. Brick stack height including the kiln car height is taken as 1.38 m. There is a clearance of 100 mm between the stack and the kiln roof. To produce certain quality bricks/ceramics, a particular temperature distribution throughout the kiln needs to be maintained. This temperature distribution with respect to the kiln length is known as Tunnel kiln curve. To achieve the Tunnel kiln curve obtained from industry for ordinary brick type, some design parameters need to be optimized for a given geometry. Selection of these optimized design parameters are obtained through a series of trial and error runs of the CFD model. The total length of the tunnel can be divided into pre-heating, firing and cooling zones. Green bricks pass through the pre-heating, then firing and finally the cooling zones, while fresh air flows in opposite direction of the brick stack move. It is to be noted that brick industries are very reluctant to disclose any of those technical secrets related to their brick kiln design. In this regard, this design is based on initial guesses of those parameters and slowly come up with best performing scenario with respect to considered Tunnel kiln curve. To achieve the Tunnel kiln curve, the design parameters that need to be played around are gas and air flow rates, flow directions, their inlet-outlet number, spacing and placements at different locations of the kiln are considered very crucial. Other important parameters that are varied include brick stack placement with respect to air and gas inlet-outlets, gaps between iv kiln roof and stacks and gaps between two consecutive stacks. To supply adequate air, a large rectangular air inlet with an area of 0.8 m2 is placed at the roof of the exit end of the kiln. To maintain the air temperature distribution as given in Tunnel kiln curve, one intermediate size air outlet with an area of 0.4 m2 and a series of 13 rows × 12 columns small air inlet-outlets (openings) are also placed at the roof of the kiln in the cooling zone. All these heated air has been transferred to dryer to dry the green bricks. A series of 12 rows × 12 columns of gas inlets are placed in the roof of the firing zone. At the entry end of the tunnel, a flue gas outlet with an area of 0.8 m2 is placed in the roof. Due to three dimensional nature of the kiln geometry, the CFD simulation of the whole system would be very time consuming. A close look of the geometry dictates that, a one-sixth slit of the total geometry (100 m × 3.24 61 × m) containing 1 row × 75 stacks of bricks is enough to simulate the whole geometry of the kiln. This modelled geometry is meshed and mesh independency is checked using ANSYS Mesh. Turbulence, combustion and radiation models are adopted to simulate a realistic Tunnel kiln environment using ANSYS CFX Pre. Several model runs are performed until the simulated temperature distributions obtained closely replicate the Tunnel kiln curve of the industry. From these simulations, the optimum Tunnel kiln design is suggested. The resulting CO2 and NO emissions are also obtained from these simulations. Gas inlet velocity is proposed to be 6 m/s with an inlet diameter of 25 mm. Gas velocity direction is suggested to be normal to the kiln roof. Air flow direction should be at 14o with kiln roof towards firing zone. Gaps between brick stacks and the kiln roof should be about 200 mm. To get a uniform distribution of heated gases, positions of the brick stacks are such that on each occasion of its changed position it would be just directly below the inlet jets. Gaps between two consecutive brick stacks should also be reduced to 200 mm instead of the initially assumed 400 mm spacing. Hence additional number of bricks could be accommodated inside the kiln at a time which will result higher production of bricks with the same amount of fuel

A Qualitative Study on Development of Enriching Performance Management System at a Pharma-Company

This case study aimed to develop a sample of enriching the performance management system using qualitative method. The job post of Import Executive in a pharma company has been selected as a sample. After taking consent from the management, a semi-structured interview approach with all related employees was undertaken. A comparison of existing performance management system was done with three other organizations of the same industry to provide a more comprehensive approach. Firstly, a systematic job evaluation was performed to transform traditional job description into competency based job description and implement job specific performance appraisal. This resulted in enrichment of performance management system. Peer evaluation and appraisal training for the supervisors have been suggested for a more comprehensive insight and a greater employee satisfaction with the performance management process

Paying health workers for performance in Battagram district, Pakistan

<p>Abstract</p> <p>Background</p> <p>There is a growing interest in using pay-for-performance mechanisms in low and middle-income countries in order to improve the performance of health care providers. However, at present there is a dearth of independent evaluations of such approaches which can guide understanding of their potential and risks in differing contexts. This article presents the results of an evaluation of a project managed by an international non-governmental organisation in one district of Pakistan. It aims to contribute to learning about the design and implementation of pay-for-performance systems and their impact on health worker motivation.</p> <p>Methods</p> <p>Quantitative analysis was conducted of health management information system (HMIS) data, financial records, and project documents covering the period 2007-2010. Key informant interviews were carried out with stakeholders at all levels. At facility level, in-depth interviews were held, as were focus group discussions with staff and community members.</p> <p>Results</p> <p>The wider project in Battagram had contributed to rebuilding district health services at a cost of less than US$4.5 per capita and achieved growth in outputs. Staff, managers and clients were appreciative of the gains in availability and quality of services. However, the role that the performance-based incentive (PBI) component played was less clear--PBI formed a relatively small component of pay, and did not increase in line with outputs. There was little evidence from interviews and data that the conditional element of the PBIs influenced behaviour. They were appreciated as a top-up to pay, but remained low in relative terms, and only slightly and indirectly related to individual performance. Moreover, they were implemented independently of the wider health system and presented a clear challenge for longer term integration and sustainability.</p> <p>Conclusions</p> <p>Challenges for performance-based pay approaches include the balance of rewarding individual versus team efforts; reflecting process and outcome indicators; judging the right level of incentives; allowing for very different starting points and situations; designing a system which is simple enough for participants to comprehend; and the tension between independent monitoring and integration in a national system. Further documentation of process and cost-effectiveness, and careful examination of the wider impacts of paying for performance, are still needed.</p

Operation of brick kilns in Bangladesh-a comparative study

This paper presents an investigation on current use of brick kiln technologies in Bangladesh. There are around five thousand established and numerous make-shift brickfields of various capacities all over the country. Most of the kilns in Bangladesh are fixed chimney (FCK) type, which are somewhat old technology and sources of pounding pollutions. Recently the Department of Environment (DoE) of the Bangladesh Government has directed brickfield owners to switch to comparatively better environment friendly technologies like Zigzag, Hybrid Hoffman (HHK) and Vertical Shaft (VSK) kilns. Most of brickfield owners are not familiar with these kilns and thus reluctant to make over due to lack of industrial knowledge and financial support. However few companies have implemented these technologies on pilot-scale and are yet to demonstrate their full financial viability. As such, broad range technical information along with financial analysis of these technologies is presented here. A set of recommendations are prepared in relation to these technologies suited to their investment opportunity, land accessibility, energy and raw-material supply, labour availability and other requirements. Amongst the three technologies, HHK is the most suitable one for large-scale production whereas FCK if modified and converted into Zigzag kiln will be relatively fuel efficient and less polluting. On the other hand VSK, which are comparatively smaller in capacity, can be made popular in rural Bangladesh. The payback periods of these three kilns are 3.14, 3.27 and 2.62 years respectively, whereas CO2 emission potentials are 22.20, 15.86 and 28.54 tCO2e, respectively compared to 38.06 tCO2e for FCK

A Qualitative Study on Development of Enriching Performance Management System at a Pharma-Company

This case study aimed to develop a sample of enriching the performance management system using qualitative method. The job post of Import Executive in a pharma company has been selected as a sample. After taking consent from the management, a semi-structured interview approach with all related employees was undertaken. A comparison of existing performance management system was done with three other organizations of the same industry to provide a more comprehensive approach. Firstly, a systematic job evaluation was performed to transform traditional job description into competency based job description and implement job specific performance appraisal. This resulted in enrichment of performance management system. Peer evaluation and appraisal training for the supervisors have been suggested for a more comprehensive insight and a greater employee satisfaction with the performance management process

A Qualitative Study on Development of Enriching Performance Management System at a Pharma-Company

This case study aimed to develop a sample of enriching the performance management system using qualitative method. The job post of Import Executive in a pharma company has been selected as a sample. After taking consent from the management, a semi-structured interview approach with all related employees was undertaken. A comparison of existing performance management system was done with three other organizations of the same industry to provide a more comprehensive approach. Firstly, a systematic job evaluation was performed to transform traditional job description into competency based job description and implement job specific performance appraisal. This resulted in enrichment of performance management system. Peer evaluation and appraisal training for the supervisors have been suggested for a more comprehensive insight and a greater employee satisfaction with the performance management process

Computational and theoretical chemistry of newly synthesized and characterized 2,2’-(5,5’-(1,4-phenylene)bis(1H-tetrazole-5,1-diyl))bis-N-acetamides

Abstract Energetic heterocycles, including pyridines, triazoles, and tetrazoles, exhibit greater density, heats of formation, and oxygen balance compared to their carbocyclic counterparts, making them a promising approach for synthesizing novel bis-tetrazole acetamides. Synthesized compounds A-F, some of which feature a chlorine atom attached to the phenyl ring, serve as valuable synthons for aryl coupling reactions. Analysis via 1H-NMR and 13C-NMR spectroscopy, as well as density functional considerations through B3LYP functional correlation with 6-311 +  + G(d) and 6-31G(d) basis set, revealed the observed LUMO/HOMO energies and charge transfer within the molecule. Additionally, the dipole moment, chemical hardness, softness, ionization potential, local reactivity potential via Fukui indices and thermodynamic properties (entropy, enthalpy, and Gibbs free energy) of the molecule were calculated through density functional theory studies. In addition, Molecular Docking studies were conducted to investigate the anti-cancer potential of synthesized heterocyclic compounds against caspase 3, NF-KAPPA-B and P53 protein. Molecular docking analysis demonstrated a potent interaction between 2,2’-(5,5’-(1,4-phenylene)bis(1H-tetrazole-5,1-diyl))bis-N-(2,4-dinitrophenyl) acetamides (6d) and TP53 and NF-KAPPA-B with binding energies of − 11.8 kJ/mol and − 10.9 kJ/mol for TP53 and NF-KAPPA-B, respectively. Similarly, 2,2’-(5,5’–(1,4-phenylene)bis(1H-tetrazole-5,1-diyl))bis-N-(2-chlorophenyl) acetamides (6f) exhibited a strong interaction with caspase-3 with binding energy of -10.0 kJ/mol, indicating their potential as therapeutic agents against these proteins. Furthermore, the findings of current study was further strengthen by 100 ns molecular dynamics (MD) simulations. Finally, theoretical studies of oxygen balance and nitrogen percentage suggest that these molecules can be utilized as energetic materials. Graphical Abstrac

Update on the eradication of 'Helicobacter pylori' infection in adult and pediatric patients from the northern region of Pakistan

'Helicobacter pylori' infection is associated with different gastric diseases, notably gastric cancer. The present study is aimed at comparing the effectiveness of various 'H. pylori' eradication regimens among adult and pediatric patients. A total of 3178 (396 children) patients were recruited. 'H. pylori' infection was diagnosed by nuclear stable isotopic 13C urea breath test (UBT) and positive patients were randomly allocated first-line eradication regimens. The second or third-line regimens were assigned to those who had failed first-line treatment. A negative UBT at least 4 weeks after the completion of treatment indicated a successful eradication of 'H. pylori'. Eradication rates (ER) by per-protocol (PP) and intention-to-treat (ITT) analysis were recorded. The overall prevalence of 'H. pylori' infection was 61.2% and slightly higher in males as compared to females. The modified concomitant therapy showed higher PP (77.8%) and ITT (72.7%) ER as first-line treatment. Among second-line therapies, PP/ITT ER of 63.6% / 55.3% were observed for quadruple therapy in adults. Standard triple therapy with probiotic and modified concomitant therapy as first-line and quadruple therapy as a second line thus is the choice for 'H. pylori' eradication in adult gastric disease patients. In pediatric patients, standard triple therapy was more effective as a first-line with about 68.8% ER.Eine 'Helicobacter pylori'-Infection ist mit verschiedenen gastrischen Krankheiten assoziiert, insbesondere Magenkrebs. Diese Studie vergleicht die Effizienz verschiedener 'H. pylori'-Ausrottungs-Methoden bei erwachsenen Patienten und Kindern. Insgesamt wurden 3178 (396 Kinder) Patienten rekrutiert. Eine 'H. pylori'-Infection wurde mittels 13C-Harnstoff-Atemtest (UBT) diagnostiziert, und positive Patienten wurden nach dem Zufallsprinzip verschiedenen "first-line" Behandlungsverfahren zugeordnet. "Second" oder "third-line"-Behandlungen erhielten diejenigen, bei denen die erste Behandlung nicht erfolgreich war. Ein negativer UBT mindestens 4 Wochen nach der Beendigung der Behandlung indizierte die erfolgreiche Vernichtung von 'H. pylori'. Ausrottungsraten (ER) durch "per-protocol (PP)" und "intention-to-treat (ITT)"-Analysen wurden erfasst. Mit 61.2% waren etwas mehr Männer als Frauen infiziert. Die "modified concomitant"-Therapie zeigte höhere PP (77.8%) und ITT (72.7%) ER als erste Behandlung. Bei den "second-line"-Therapien wurden PP/ITT ER von 63.6% / 55.3% für die "quadruple"-Therapie in Erwachsenen beobachtet. Die "standard triple"-Therapie mit Probiotic und die "modified concomitant"-Therapie als "first" und die "quadruple"-Therapie als "second-line" ist daher die Wahl für eine 'H. pylori'-Vernichtung in erwachsenen Patienten mit gastrischen Krankheiten. In Kindern war die "standard triple"-Therapie effizienter als "first-line"-Behandlung mit ~68.8% ER