Concrete corrosion induced by sulfuric acid

Concrete sewer pipes are known to suffer from a process of hydrogen sulfide gas induced sulfuric acid corrosion. This leads to premature pipe degradation, performance failure and collapses which in turn may lead to property and health damage. To change the existing post-reactive attitude of managing companies, easy to use and robust models are required to be developed which currently lack reliable data to be correctly calibrated. This paper focuses on laboratory experiments of establishing concrete pipe corrosion rate by submerging samples into sulphuric acid solution for a duration of up to 120 days under 10-30ºC temperature regimes. The results showed that some samples at very early stage of the corrosion process gained overall mass and density with reverse process over time. Overall, in lab conditions the corrosion rates of 5-25mm/year were observed

Corrosion induced by sulfuric acid – method of concrete material properties upgrade?

Sulphuric acid induced concrete corrosion is an acknowledged problem in water and by large waste water industry, where sewer pipes are most at risk due to early failure. Currently, there are very little studies of concrete behaviour due to sulfuric attack. This paper tries to fill some of the knowledge gaps in the field and reports on experimental results of concrete samples being emerged into acidic environment for a length of three months under different temperatures and pH conditions. In this study, it was revealed that apart from the predicted corrosion rates concrete samples gained overall mass in the first weeks, which had a positive impact on their density and hence compressive strength

Hands-on delivery of group business project

The delivery of Business Project module to Applied Engineering & Management students across different programmes is carried over two terms in two years. During this time students are exposed to a variety of subjects and topics covering all aspects of business from basic theoretical principles to real life application. Students are expected to obtain ‘HANDS-ON’ experience and become exposed to Group Business Project (GBP), where second year students form a company and employ first year students, to work collaboratively on a real project offered by external business-client local to London and/or Kent

Evaluating the Effects of Standardized Patient Care Pathways on Clinical Outcomes

The main focus of this study is to create a standardized approach to evaluating the impact of the patient care pathways across all major disease categories and key outcome measures in a hospital setting when randomized clinical trials are not feasible. Toward this goal I identify statistical methods, control factors, and adjustments that can correct for potential confounding in observational studies. I investigate the efficiency of existing bias correction methods under varying conditions of imbalanced samples through a Monte Carlo simulation. The simulation results are then utilized in a case study for one of the largest primary diagnosis areas, chronic obstructive pulmonary disease (COPD) at the University of Tennessee Medical Center. The analysis of the COPD pathway effects on the readmission rates showed a significant positive impact, with reduction in the probability of readmissions between 12% and 16%. The reduction in the length of stay was reported across all the models with historical controls, but the effect was not statistically significant

Monitoring CO2 and H2S emission in live Austrian and UK concrete sewer pipes

Corrosion of concrete sewer pipes induced by sulfuric acid is an acknowledged problem and a ticking time-bomb to sewer operators. Whilst the chemical reaction of the corrosion process is well-understood, the indirect roles of other parameters in the corrosion process which are found in sewer environment are not highly reflected on. This paper reports on a field studies undertaken in Austria and United Kingdom, where the parameters of temperature, pH, H2S and CO2 were monitored over a period of time. The study establishes that (i) effluent temperature and pH have similar daily pattern and peak times, When examined in minutes scale, (ii) H2S and CO2 have an identical hourly pattern, (iii) H2S instant or shifted relation to effluent temperature is governed by the root mean square value of CO2

ZASTOSOWANIE METOD STEGANOGRAFICZNYCH DO ATAKÓW W SYSTEMACH INFORMACYJNO-KOMUNIKACYJNYCH

An analysis of steganography methods that are can be potentially used as instruments in attacks on information and communication systems is presented. The possible solutions to ensure resilience to such attacks are presented.W artykułe został przedstawiony przegląd istniejących i potencjalnie dostępnych technik steganograficznych, które mogą zostać użyte jako narzędzia do ataków na systemy informacyjne i komunikacyjne. Podano możliwe sposoby zapewnienia ochrony przed takimi atakami

An application of a parametric transducer to measure the acoustical properties of a living green wall

Greening of urban spaces provides a number of environmental benefits. Green living walls (GLW) is a most typical example of greening which is also known for its ability to absorb unwanted noise. However, this ability of GLW to absorb noise is rather hard to quantify, because there is a lack of reliable experimental methods to measure it in-situ. This work reports on a new method to measure the absorption coefficient of LGW which makes use of a highly directional parametric transducer and acoustic intensity method. This method is tested in under controlled laboratory conditions and in a typical street environment. The results of these experiments demonstrate the ability of the method to measure the absorption of a LGW. It also enables us to quantify the effects of the plant type and moisture content in the soil on the ability of the LGW to absorb sound. The proposed method has certain benefits over ISO354-2003 and CEN/TS 1793-5:2003 standard methods

'Pro' and 'hands-on' approach in business project delivery

The delivery of Business Project module to Applied Engineering & Management students across different programmes is carried over two terms in two years. During this time students are exposed to a variety of subjects and topics covering all aspects of business from basic theoretical principles to real life application including Economics, Entrepreneurship, Product Development, Innovation, Law, Social & Corporate Responsibility, Marketing, Finance, Accounting, etc. The delivery of such a multi-content module by a single person would mean: (i) a stale delivery by-the-book and/or (ii) that the students do not get the best experience in all offered topics. Considering the above and following reflection into enhancing and flavouring students’ experience it was decided to utilise ‘PRO’ approach in delivering Business Project module, which meant that each week the lecture on a specific topic was delivered by a specialist in the field. Additionally, students were expected to obtain ‘HANDS-ON’ experience and become exposed to Group Business Project (GBP), where second year students formed a company and employed first year students, to work collaboratively for a real client and the business project they offered to students. The client would effectively be an external company or organisation, which in many cases was an SME based in Kent or London, and keen to collaborate with local students who potentially can become their interns and employees. Students have found these changes ‘beneficial and encouraging’, lectures ‘much more interesting’ and agreed that GBP is providing them with ‘confidence of securing graduate employment in their area of interest’

In-situ acoustic absorption of a living green wall

Data on the ability of a living green wall to absorb sound in-situ is scarce. In this work a directional parametric transducer was used to project sound on the centre of a living green wall to minimise the ground reflection and scattering from it edges. The sound pressure and particle velocity in the incident and reflected sound waves were measured with an intensity probe and used to estimate the acoustic absorption coefficient. These data were also used to estimate the ability of a living wall to scatter the incident sound. It was found that a living wall system that consists of several rectangular cells with plants can support acoustic resonances at frequencies which are controlled by the cell dimension and wall thickness. Some of these resonances are reduced or disappear when the wall is treated with a plant with a relatively high leaf area density. There is evidence that in some cases plants can scatter sound coherently resulting in an apparent decrease in the absorption coefficient. These effects need to be accounted for by a refined numerical model which is yet to be developed

Acoustic monitoring of hydraulic resistance in partially full pipes.

Hydraulic losses in sewer pipes are caused by wall roughness, blockages and in-pipe sedimentation. Hydraulic resistance is a key parameter that is used to account for the hydraulic energy losses and predict the sewer system propensity to flood. Unfortunately, there are no objective methods to measure the hydraulic resistance in live sewers. A common method to estimate the hydraulic resistance of a sewer is to analyse collected CCTV images and then to compare them against a number of suggested hydraulic roughness values published in the Sewer Rehabilitation Manual. This thesis reports on the development of a novel, non-invasive acoustic method and instrumentation to measure the hydraulic roughness in partially filled pipes under various structural and operational conditions objectively. This research presents systematic laboratory and field studies of the hydraulic and surface water wave characteristics, of shallow water flows in a sewer pipes with the presence of local and distributed roughness, in order to relate them to some fundamental properties of the acoustic field measured in the vicinity of the flow surface. The results of this thesis indicate that for the local roughness the energy content of the reflected acoustic signal is an indicator of the pipe head loss and hydraulic roughness. In the case of the distributed roughness, the variation in the temporal and frequency characteristics of the propagated sound wave can be related empirically to the mean flow depth, mean velocity, wave standard deviation and hydraulic roughness