Segment-based resilience response and intervention evaluation of water distribution systems

The consideration of isolation valves and segments is essential for evaluating the water service and resilience of water distribution systems when shutdowns are required under pipe failure. However, little work has been done on assessing the resilience response and intervention based on segments. This study investigates the impact of intervention (valve density and protection of critical segment) and response (recovery time and recovery sequence) on system resilience taking valve layout into consideration. An algorithm to identify segments based on the graph theory is proposed. Resilience is quantified using the satisfactory rate of the water supply demand. Critical segments are ranked based on resilience analysis. The resilience evaluation method is applied to a case study network. It is found that valve optimization can significantly reduce the number of valves without considerably decreasing the resilience performance. Valve density and the protection of critical segment can reduce the severity of pipe failure, while efficient recovery response can reduce the severity and shorten the duration of pipe failure simultaneously. The criticality of segments depends on the segment location and hydraulic interdependency among segments.

Adaptive restart scheme based on active injection current ratio for half-bridge MMC-HVDC with overhead transmission lines

Modular multilevel converter for high voltage DC system has great potential as the key role in global energy interconnection. Adaptive reclosing or restarting after suffering from short-circuit faults is a critical segment to realize safe and stable operation. An adaptive restart scheme for the half-bridge sub-module transmission system is proposed, which is based on the active current injection of the auxiliary fault discriminate module. Combined with the engineering experience, the transient characteristics of the line current during the fault restart stage are analyzed. The ratio of the current peaks at both ends of the fault point is used as the criterion. Moreover, the restart current suppression strategy is introduced into the adaptive restart scheme. It provides a decision-making basis for discriminate the property of the fault and improves the success rate of fault restart. The simulation results show that after the external auxiliary module is introduced into the adaptive restart stage, the restart current does not exceed the rated value. Finally, The permanent fault and the transient fault can be successfully distinguished, providing a reliable guarantee for the subsequent action decision of the protection devices.

Private labels – customer profile and changes in trade during pandemic

Purpose: This article focuses on private labels, which play a crucial role in the retail market.This article aims to examine the market of private labels in the Czech Republic and reveal the customer profile of private labels in the Czech market. Design/methodology/approach: This article incorporates the results of the author's research devoted to various aspects of private labels and trade. The author used an online questionnaire for the research. This questionnaire was divided into several parts and prepared based on the literature search of statistics, reports, papers, and scientific studies. Findings: Large retail chains can achieve more than 30% of sales from private labels. The nature of the private label market is changing significantly. Therefore, the customer profile is changing too. The author's research revealed that the most critical segment for private labels is women, specifically single women with an income of up to 20,000 CZK, aged under 27-36, who live in medium-sized cities with up to 100,000 inhabitants. Research limitations/implications: In the current Covid-19 pandemic, the results can contribute to more effective collaboration with customers. In the future, it is intended to develop research on other aspects that affect the operation of private labels. Practical implications: It is clear from the research results that large retail chains should focus on certain specific segments, especially women with the above profile. According to research, this segment is the most crucial segment for retail chains and should focus on it. Originality/value: The article focuses on the changes during the Covid-19 pandemic. At this time, there were changes in shopping behavior, which are listed in the article.

Improving Water Distribution Systems Robustness through Optimal Valve Installation

This study proposes a framework for improving the robustness of water distribution systems using the optimal valve installation approach with regard to system reinforcement. To improve the robustness in valve design, this study introduces critical segment selection technique and optimal valve location determination within the concept of segment. Using the segment finding algorithm, the segment and the unintentional isolation can be identified. To select the critical segment, a multicriteria decision technique is applied by considering the hydraulic, social and economic effect. Finally, the optimal valve locations and the number of additional valves is determined by pipe failure analysis through the trade-off relationship with the number of additional valves and the maximum damage under pipe failure situations. To verify the proposed technique, the real-world water distribution systems are applied and compared with the original design.

Identification of Barrier for Development of the Sri Lankan Small- and Medium-scale Gem Mining Enterprises: A Case Study Based on Ratnapura District

Small- and medium-scale enterprises (SMEs) have been recognized as a critical segment and lifeline to push development and social improvement in Sri Lanka. Several studies have pointed out that people involved in some informal sector SME activities are opposing to develop that sector due to many reasons. Further, it will be same for the gem mining sector too. Along these lines, this examination may be directed towards recognizing those essential trademarks of gem mining SMEs. This study discusses the primary issues which thwart those improvements in this industry and will suggest necessary arrangements. Methodology should also overcome these imperatives. This study is composed of an investigation in Ratnapura locale with organized questionnaire surveys and meetings with magic stakeholders. Furthermore, this creates far-reaching expositive expression audit. The vicious cycle of the SME model may be utilized to study the prevailing barriers in this industry. Discoveries of the exploration demonstrate that this business is male-dominated. Different ages are also included. Marketing, technology, data and administration and administrative issues are identified as main barriers and basic problems in gem mining industry. Furthermore, gems prices are kept at falsely low level toward those purchasers who come for repeat buys. This is the major barrier in the development of lifestyle of the gem mining people who spend a miserable life, while cunning gem buyers are living a luxurious life on the shoulders of poor. This research endeavour will be directed towards a situational examination.

Forensic Engineering Analysis Of loading Dock Traffic Patterns

An Efficient Transportation System Includes The Safe And Efficient Movement Of Goods For Distribution to Consumers. Trucking Transport Is A Major Component Of The Transportation System Which Delivers goods To Consumers. The Flexibility Of Door-To-Door Deliveries That Is Not Available Through Other Modes of Transportation Such As Rail Or Ship, Makes Trucking Transport The Final Critical Segment Of The Goods transport Process. Distribution And Terminal Facilities For Truck Transport Are Generally Designed To Allow trucks To Back Into Loading Dock Areas. In Addition To Providing Proper Dock Heights And Bay Widths, The infrastructure Of These Facilities Must Provide Adequate And Proper Traffic Circulation Patterns Which In turn Allow For Safe And Proper Backing Of Trucks To The Loading Docks. This Paper Will Detail The Analysis of Two Facilities Where Road Widening Projects Created A Disruptive Change In The Traffic Circulation Pattern, which In One Case Required The Reconstruction Of The Site To Accommodate Trucking Deliveries, And in The Other Required The Change In Use Of The Property To One That No Longer Relied On Trucking Deliveries.

Design and Development of Hydrodynamic Lubricating System of Large-Scale Mill Oil-Film Bearing Test Rig

The lubricating system is the critical segment to ensure the good operation of bearing subsystem and the whole mill system. To keep pace with the advanced domestic and outdoors technologies, it is emergent to design and develop the mechatronic test rig of mill oil-film bearing. According to the detailed design parameters and design principles of lubricating system, its main modules and the lubricating mechanism are designed and implemented. The according 2D drawings and 3D solid models are successfully established. Consequently, the prototype is developed, and runs well in practical tests on mechanical parameters of mill bearing. Moreover, some further improvements are also made to better the performances of lubricating system.