Repair Work Research Articles

The work of repair: Capacity after colonialism in the timber plantations of South Africa By ThomasCousins, New York: Fordham University Press. 2023. 320 pp.

The work of repair: Capacity after colonialism in the timber plantations of South Africa By ThomasCousins, New York: Fordham University Press. 2023. 320 pp.

Prospects for reducing resistance of ash collecting apparatus

Various variations of reducing the aerodynamic resistance of devices with a complex flow-through configuration are considered. About 50% of power plants in the Russian Federation operate on coal, with two-stage cleaning used in the ash collection process. Modern coarse ash collectors allow achieving an efficiency of 55 – 80% depending on their service life. It is advisable to reduce the number of cleaning stages by upgrading them with modern cleaning devices that allow achieving high efficiency of cleaning the dusty flow and subjecting this cleaning complex to less repair work. IVACis an inertial-vacuum ash collector, which can achieve the capture of a wide range of studied particles (1 – 100 μm) with an efficiency of up to 99%. This device was tested at the Omsk CHP Plant, but it was found to feature an increased aerodynamic resistance, as well as high efficiency. The objective of this work is to keep an aerodynamic resistance to 660 Pa (the resistance of the cyclone apparatus so that the apparatus can be used as the first and, consequently, as two stages of purification) while maintaining the efficiency of the apparatus. The results of changing the configuration of the flow part of the IVAC are analyzed, the model submitted for patenting after numerous is considered. The research methodology is the analysis of a numerical experiment in ANSYS CFX using the k-ε mathematical model (ash mass content of 70 g / kg; One-Way Coupling). In conclusion, recommendations are proposed for further prospects of IVAC research.

Diagnosis of ring cracks on the shafting line of a turbo unit

Due to the growing number of accidents associated with damage to turbine unit shafts, there is a pressing need to diagnose the occurrence and growth of ring cracks not only during planned repair work on the turbine unit, but also directly during its operation to prevent emergency failures and costly repairs of the machine. Ring cracks that develop in the shafting do not lead to an increase in the level of vibration of the rotor or its support bearings and, therefore, cannot be detected by standard operational vibrodiagnostic systems. In this paper we propose a method that allows for the diagnosis of the occurrence and growth of ring cracks on the turbine unit shafting. The method is based on the influence of the depth of an annular crack in the shaft on the angle of its twist during machine operation. The presence of this relationship is determined through calculations based on the parameters of the experimental low-pressure turbine 2, used by the Central Boiler and Turbine Institute named after I. I. Polzunov. The practical implementation of this method is proposed to be carried out using the twist angle determination technique developed based on the discrete-phase method by means of measuring and analyzing changes in the shaft twist angle during turbine unit operation. Technically, this is achieved by employing a system consisting of inductors and sensors fixed to the stator and rotor parts of the machine. The proposed method can be used as a supplement to existing methods of operational control of the actual condition of the shafting, as well as, in the future, to assess the actual efficiency of the turbomachinery cylinders.

ANALYSIS OF THE CAUSES OF ACCIDENTS IN THE OIL AND GAS INDUSTRY

In the modern world, the oil and gas industry plays a key role in ensuring the energy security of countries. An important problem of this industry is the high level of accidents on main pipelines. The importance of issues of ensuring the safety of production processes and working conditions of personnel is obvious: accidents that occur at enterprises can paralyze work for a long time, attracting the attention of the media and regulatory authorities, causing not only financial but also significant image damage. In connection with the above, the analysis and statistical study of accidents in this area have become relevant in recent years. Occupational safety measures include risk assessment at workplaces, briefings, medical examinations, provision of personnel with personal protective equipment, special assessment of workplaces, occupational safety days, etc. In order to restore the technical and economic indicators of the oil and gas industry, increase reliability and trouble-free operation, complexes of measures are carried out to repair, reconstruct and modernize the components of the main gas pipeline. Ensuring industrial safety during repair work depends on both the reliability of the process equipment and the reliability of the personnel, since a significant number of accidents and incidents occur due to reasons related to the influence of the human factor. Many studies have been devoted to the problem of management in the field of labor protection and ensuring safety at work. Despite the significant number of works, a practical lack of developments on the issues of managing the processes of ensuring safety and labor protection at enterprises in the oil and gas industry has been discovered, which indicates the need for a more in-depth study of this topic.

Mending the Fabric: the Contentious, Collaborative Work of Repairing Broadband Maps

In 2011, the United Nations declared Internet access to be a basic human right. Achieving universal Internet access has been a longstanding goal of governments around the world. In the United States (US), provision depends primarily on decisions made by Internet Service Providers (ISPs) driven essentially by commercial market concerns. To encourage deployment in underserved regions, the US federal government has recently allocated unprecedented funding, with distributions guided by the information in broadband maps, spatial representations of current Internet access and quality published by the Federal Communication Commission. Yet, these maps are known to be inaccurate, especially for populations that are marginalized, such as tribal and rural residents. We are interested in the collaborative and contentious efforts to repair the data contained in broadband maps, and particularly by the efforts of citizen groups and local government to counter claims made by ISPs. In this paper, we study these efforts via interviews of 14 individuals involved in various local and regional roles, in policy, IT, advocacy, and research. We draw upon frameworks of repair and of data activism to ask who does this work and why; what tangible and intangible tools are brought to bear; and how the structural context simultaneously empowers and burdens repair workers. In doing so, we make three contributions: (i) we critique the process and system for broadband map repair for the burdens it places on historically marginalized groups to demonstrate how they have been left out of expansion and how their experiences are otherwise silent in official records; (ii) we bring together analytical concepts from repair and data arenas to examine repair work that is substantially shaped by socio, political, and economic context; and (iii) we illustrate how viewing broadband data workers as activists reveals the inadequacy of current tools and the opportunity for better support for their long-term, contextualized, and mediated efforts.

Features of Providing Air Temperature and Humidity Parameters in the Engine Room Working Area at Sewage Pumping Stations

Statement of the problem. There is an important task for engineers to improve the working conditions of workers in industrial facilities. The waste water system includes a large number of structures with different temperature and humidity microclimate characteristics. The possibility has been discussed to improve these characteristics by redistributing air flows in the engine room of a city sewage pumping station with PLI panel. Results. There are the results of the temperature and humidity microclimate parameters research in the working area of the engine room at a high-voltage sewage pumping station which is located in Moscow. The author has proved the possibility of use the cooled air from the machine room lower level in a high-voltage pumping station at the machine room main working area. It has been described the calculation features of the heat transfer coefficients in the proposed model for local ventilation at the main technological working area. It has been described the results of temperature and humidity parameters instrumental study in the main working area and the lower level. Conclusion. Thelocal ventilation systems could be used for the working area, where an employee performs repair work of the main technical equipment in a sewage pumping station. The balanced mathematical thermal model includes PLI panel’s potential location.

Self-centering rocking steel frame with column mid-height uplift: Experimental and numerical investigation

This paper proposes a self-centering rocking steel frame with column mid-height uplift (SCRSF-CMU) that exhibits high post-yield stiffness and energy dissipation capacity. The hysteretic performance of the SCRSF-CMU was investigated through cyclic loading tests. A numerical model of the SCRSF-CMU was established and validated against experimental results. Subsequently, the seismic performance of the SCRSF-CMU was compared with that of the self-centering rocking steel frame with column base uplift (SCRSF-CBU) using nonlinear time history analysis. Finally, the seismic responses of the SCRSF-CMU and SCRSF-CBU under varying earthquake intensities were analyzed using the endurance time analysis. The results indicate that the designed SCRSF-CMU demonstrates excellent lateral force resistance, energy dissipation, and self-centering capabilities. The rocking effect and the restoring force of the post-tensioned steel strands effectively controlled the residual lateral displacement of the specimens. The multi-scale numerical model of the SCRSF-CMU accurately captured its hysteretic behavior and deformation patterns. Compared to the SCRSF-CBU, the SCRSF-CMU exhibited superior rocking deformation capacity, post-yield stiffness, and hysteretic energy dissipation. Under MCE excitation, both SCRSF-CMU and SCRSF-CBU showed uniform inter-story drift distribution with minimal residual deformation, creating a satisfactory condition for the post-earthquake repair work if necessary. The high post-yield stiffness of the SCRSF-CMU was more effective in reducing both maximum and residual displacements. Endurance time analysis revealed that SCRSF-CMU and SCRSF-CBU exhibited relatively uniform inter-story drift distribution under SLE, DBE, and MCE earthquakes. Under FE excitation, the inter-story drift ratio of both structures were nearly identical; however, under DBE and MCE excitations, the maximum roof drift ratio and inter-story drift ratio of the SCRSF-CBU were larger, indicating that the SCRSF-CBU had higher deformation demands than the SCRSF-CMU.

Changes in the peel strength between the painting and first lining papers in Japanese scroll model samples

To maintain the permanence of a painting in a hanging scroll until subsequent repairs are made, inhibiting not only the deterioration of the painting and lining papers but also inhibiting decrease in the adhesiveness between them is important because the first lining process significantly influences the mechanical support to the painting paper by attachment. Several studies have been conducted on the deterioration attributed to each component of the lining system. This study evaluated the adhesiveness behaviour by peel strength in the lined complex depending on the painting and lining materials with varied concentrations, as well as the fibre type of the lining paper. The lined complex consisting of the untreated painting paper showed the highest initial peel strength owing to the significant cohesiveness of the wheat starch paste layer, which was attributed to the paper's higher wettability and permeability, even though substrate failure occurred with longer ageing times. Degradative materials such as Cu2+ attributed to pigments in the painting paper decomposed starch and decreased adhesiveness the fastest. Lined complexes coated with animal glue containing alum or Cu2+ in the painting paper maintained the lowest peel strength during ageing owing to lower wettability and permeability, resulting in interfacial failure between the animal glue and the wheat starch paste layer. In addition, adhesiveness varied with different fibre types of the lining paper, depending on combined factors such as fibre length, surface roughness, shape, and intensity of hydroxyl groups. Thus, variable conditions attributed to fibre characteristics, materials used for lining, and degradative products in the painting paper influenced the changes in adhesion and adhesiveness. This variation contributed to different lining effects that influenced the life expectancy of the hanging scroll and determined the efficiency of the subsequent repair work.

Digital indicator for evaluating the hydraulic control system of the tractor gearbox

The effi ciency of using energy-saturated tractors in agriculture largely depends on the level of preparation for fi eld work, which in turn depends on an objective assessment of the general technical condition of components and assemblies to justify the repair and maintenance work carried out. Various diagnostic tools are widely used for a non-selective assessment of the general technical condition of the internal combustion engine: motor testers, crankcase gas fl ow meters, etc. However, there are no such means to assess the technical condition of the transmission (gearbox) of energy-saturated equipment of domestic production. In conditions of logistical remoteness from service centers, there is a need to develop digital indicators to assess the general technical condition of a hydraulically controlled gearbox according to the time of the transition process, allowing the end user to contact the dealer’s service company in a timely manner (The purpose of the study) to study the status of the issue, analyze the NTD and search experiments and develop an experimental digital indicator for monitoring the general technical condition of boxes transmission changes of energy-saturated tractors of domestic production according to the transition process in the hydraulic control system. (Materials and methods) Conducted an analysis, studied the NTD, as well as methodological guidelines for diagnosing and managing the reliability of agricultural machinery, previously produced control and diagnostic equipment, KI-112383 was chosen as an analog for the development of a digital indicator. It has been established that the method of transient characteristics is widely used to diagnose rapidly changing processes. Monitoring the time of the transition process in the hydraulic control system is a necessary diagnostic procedure that allows you to indiscriminately assess the overall technical condition of the KP of operated energysaturated tractors. (Results and discussion) the results of staged experiments using the E-14-140M ADC when running in the gearbox of the K-744R tractor on the stand showed the possibility of a comparative assessment of the general technical condition according to the transient characteristics of pressure recovery in the control system during gear shifting. To develop a prototype of the digital indicator, a virtual simulation was carried out with simulation of the algorithms of operation, and test tests were carried out on the developed laboratory installation. The developed experimental digital indicator can be used as an integrated monitoring tool to automatically determine the general technical condition of the gearbox, as well as inform the operator to minimize the infl uence of the «human» factor when changing gears. (Conclusions) For eff ective management of the general technical condition of tractors, it is necessary to pilot the implementation of the developed digital indicator, which will allow assessing the dynamics of changes in the transient pressure recovery process as a diagnostic parameter during the repair of the gearbox and under operating conditions of tractors without making changes to the design.

Barrel rifling node offset detection and subsequent optimization based on thin film in-mold decoration characteristics of the Johnson–Cook model

In this paper, a nodal detection method for the detection and optimization of barrel helix offsets is proposed. The barrel used in this experiment is a 6-helix barrel. Moreover, the special properties of the film of Polyetheretherketone (PEEK) material are used to cover the surface of the barrel helix with a virtual in-mold decoration (IMD) film, and the unique nature of the film die offset in the IMD is utilized to detect the position of the barrel helix. The area with a large die index is the area with a large helix offset in the barrel, and the IMD die index is introduced to quantify the data. The IMD die index is used to determine the helix offset of the damaged barrel. The novelty of this work is that each node can use the die index to efficiently detect the position of the barrel helix deviation, carry out subsequent optimization and repair work through the optimization of the injection molding parameters and the design optimization of the barrel and verify the experiment by comparing the results. Through the steady-state simulation research mode, different permutations and combinations of the two process parameters are simulated to study their effects. Quantitative reference indicators include but are not limited to dependent variables such as the fluid flow velocity, shear rate, temperature distribution and phase transition, and the shear heating process of the injection screw is taken into account in the mold flow analysis to ensure that the die index value is more accurate. It can be seen from the analysis results that the temperature of the barrel changes after the groove depth and groove width are changed, and the effect ratio of the groove depth is lower than that of the groove width in the same degree of size change.

Brickwork in Norway: tradition encounters a new age of industrial construction, 1905–1912

During the first decades of the twentieth century, construction technology experienced rapid developments, which also affected industrial buildings. This paper demonstrates this evolution between 1905 and 1912 through the case of the Rjukan and Notodden UNESCO World Heritage site in central southern Norway. The site was established for the purpose of producing synthetic nitrogen fertiliser by the company Hydro. There, building systems changed from timber frames with brick infill to pure brick bearing walls and finally to more sophisticated wall-braced cage buildings where steel was incorporated. Increasing the structural capacity was the answer to the growing demand for higher and larger industrial buildings. This case study presents the characteristics and establishes an initial account of the types of construction systems. Embedded steel that is concealed within brickwork can be subject to corrosion and compromise structural integrity. Studying these systems and materials in greater detail and identifying conservation issues will support future repair work. The studied buildings reveal also that used systems were not unique to this remote mountain area, but the technology used was in line with developments in leading industrial nations around the world. This places the site also in an international context of architecture and engineering history.

From Reactive to Proactive Infrastructure Maintenance: Remote Sensing Data and Practical Resilience in the Management of Leaky Pipes

The introduction of remote sensing technologies, AI and big data analytics in the utility sector is warranted by the need to provide critical services with the least disruption to customers, but also to enable preventive maintenance, extend the life cycle of infrastructure components and reduce grid loss—or overall, to exhibit ‘durability’ and ‘resilience’ when faced with the certainty of breakage and decay. In this paper, we first explore the concept of ‘resilience’ and the nature of practice from a performativist perspective in order to set the scene for discussing the impact of ‘datafication’ on maintenance practices and infrastructure durability. We then describe an instance of introducing remote sensing technologies in district heating network surveillance and leak detection: drone-operated thermographic cameras and underground wire sensors. Based on insights from this case study, we discuss the specificity of data-driven infrastructure maintenance practices, and what it means to exhibit practical resilience in relation to how such practices unfold, interrelate and evolve over time. We reflect on how the use of remote sensing technologies and data analytics (1) potentially changes district heating workers’ epistemic worlds (i.e., how knowledge emerges, is negotiated and ordered in practice) and (2) provides opportunities for ‘messy’ pipe repair work to tacitly adopt proactive and preventive logics to meet continuously evolving organizational and societal needs.

Discussion

An archaeological watching brief was undertaken at the Jedburgh Abbey Rampart during repair and construction works to consolidate and secure the ‘rampart’ wall and its face, both of which had begun to deteriorate and fail. The watching brief followed on from earlier works to investigate the construction of the ‘rampart’, which had revealed the presence of disarticulated skeletal remains behind the wall. The excavations undertaken during the repair works have helped to infer the methods employed for the construction of the ‘rampart’, likely dating to the late 18th century. During construction several burials of the former Low Kirkyard were disturbed and displaced, with the disarticulated remains of several skeletons found within the construction deposits. The watching brief also revealed the remains of five burials that were partially disturbed during construction, with skeletal remains dating from the 15th century onwards. Disturbance to earlier graves, not disturbed by the construction, were also identified, the results of which indicate changing attitudes to skeletal remains through the post medieval and early modern periods.

Abstract

An archaeological watching brief was undertaken at the Jedburgh Abbey Rampart during repair and construction works to consolidate and secure the ‘rampart’ wall and its face, both of which had begun to deteriorate and fail. The watching brief followed on from earlier works to investigate the construction of the ‘rampart’, which had revealed the presence of disarticulated skeletal remains behind the wall. The excavations undertaken during the repair works have helped to infer the methods employed for the construction of the ‘rampart’, likely dating to the late 18th century. During construction several burials of the former Low Kirkyard were disturbed and displaced, with the disarticulated remains of several skeletons found within the construction deposits. The watching brief also revealed the remains of five burials that were partially disturbed during construction, with skeletal remains dating from the 15th century onwards. Disturbance to earlier graves, not disturbed by the construction, were also identified, the results of which indicate changing attitudes to skeletal remains through the post medieval and early modern periods.

Introduction

An archaeological watching brief was undertaken at the Jedburgh Abbey Rampart during repair and construction works to consolidate and secure the ‘rampart’ wall and its face, both of which had begun to deteriorate and fail. The watching brief followed on from earlier works to investigate the construction of the ‘rampart’, which had revealed the presence of disarticulated skeletal remains behind the wall. The excavations undertaken during the repair works have helped to infer the methods employed for the construction of the ‘rampart’, likely dating to the late 18th century. During construction several burials of the former Low Kirkyard were disturbed and displaced, with the disarticulated remains of several skeletons found within the construction deposits. The watching brief also revealed the remains of five burials that were partially disturbed during construction, with skeletal remains dating from the 15th century onwards. Disturbance to earlier graves, not disturbed by the construction, were also identified, the results of which indicate changing attitudes to skeletal remains through the post medieval and early modern periods.

The finds

An archaeological watching brief was undertaken at the Jedburgh Abbey Rampart during repair and construction works to consolidate and secure the ‘rampart’ wall and its face, both of which had begun to deteriorate and fail. The watching brief followed on from earlier works to investigate the construction of the ‘rampart’, which had revealed the presence of disarticulated skeletal remains behind the wall. The excavations undertaken during the repair works have helped to infer the methods employed for the construction of the ‘rampart’, likely dating to the late 18th century. During construction several burials of the former Low Kirkyard were disturbed and displaced, with the disarticulated remains of several skeletons found within the construction deposits. The watching brief also revealed the remains of five burials that were partially disturbed during construction, with skeletal remains dating from the 15th century onwards. Disturbance to earlier graves, not disturbed by the construction, were also identified, the results of which indicate changing attitudes to skeletal remains through the post medieval and early modern periods.

Acknowledgements

An archaeological watching brief was undertaken at the Jedburgh Abbey Rampart during repair and construction works to consolidate and secure the ‘rampart’ wall and its face, both of which had begun to deteriorate and fail. The watching brief followed on from earlier works to investigate the construction of the ‘rampart’, which had revealed the presence of disarticulated skeletal remains behind the wall. The excavations undertaken during the repair works have helped to infer the methods employed for the construction of the ‘rampart’, likely dating to the late 18th century. During construction several burials of the former Low Kirkyard were disturbed and displaced, with the disarticulated remains of several skeletons found within the construction deposits. The watching brief also revealed the remains of five burials that were partially disturbed during construction, with skeletal remains dating from the 15th century onwards. Disturbance to earlier graves, not disturbed by the construction, were also identified, the results of which indicate changing attitudes to skeletal remains through the post medieval and early modern periods.

References

An archaeological watching brief was undertaken at the Jedburgh Abbey Rampart during repair and construction works to consolidate and secure the ‘rampart’ wall and its face, both of which had begun to deteriorate and fail. The watching brief followed on from earlier works to investigate the construction of the ‘rampart’, which had revealed the presence of disarticulated skeletal remains behind the wall. The excavations undertaken during the repair works have helped to infer the methods employed for the construction of the ‘rampart’, likely dating to the late 18th century. During construction several burials of the former Low Kirkyard were disturbed and displaced, with the disarticulated remains of several skeletons found within the construction deposits. The watching brief also revealed the remains of five burials that were partially disturbed during construction, with skeletal remains dating from the 15th century onwards. Disturbance to earlier graves, not disturbed by the construction, were also identified, the results of which indicate changing attitudes to skeletal remains through the post medieval and early modern periods.

Archaeological results

An archaeological watching brief was undertaken at the Jedburgh Abbey Rampart during repair and construction works to consolidate and secure the ‘rampart’ wall and its face, both of which had begun to deteriorate and fail. The watching brief followed on from earlier works to investigate the construction of the ‘rampart’, which had revealed the presence of disarticulated skeletal remains behind the wall. The excavations undertaken during the repair works have helped to infer the methods employed for the construction of the ‘rampart’, likely dating to the late 18th century. During construction several burials of the former Low Kirkyard were disturbed and displaced, with the disarticulated remains of several skeletons found within the construction deposits. The watching brief also revealed the remains of five burials that were partially disturbed during construction, with skeletal remains dating from the 15th century onwards. Disturbance to earlier graves, not disturbed by the construction, were also identified, the results of which indicate changing attitudes to skeletal remains through the post medieval and early modern periods.

Environmental analysis

An archaeological watching brief was undertaken at the Jedburgh Abbey Rampart during repair and construction works to consolidate and secure the ‘rampart’ wall and its face, both of which had begun to deteriorate and fail. The watching brief followed on from earlier works to investigate the construction of the ‘rampart’, which had revealed the presence of disarticulated skeletal remains behind the wall. The excavations undertaken during the repair works have helped to infer the methods employed for the construction of the ‘rampart’, likely dating to the late 18th century. During construction several burials of the former Low Kirkyard were disturbed and displaced, with the disarticulated remains of several skeletons found within the construction deposits. The watching brief also revealed the remains of five burials that were partially disturbed during construction, with skeletal remains dating from the 15th century onwards. Disturbance to earlier graves, not disturbed by the construction, were also identified, the results of which indicate changing attitudes to skeletal remains through the post medieval and early modern periods.