698 research outputs found
Monetising human impacts. CLeMM: Customer Led Monetising Method
Executive Summary:
This study has developed a Customer Led Monetising Method (CLeMM) to assess the monetary value of the human impacts of Highways England's operational services. CLeMM is simple in concept, easy to use and adaptable to a wide variety of situations enabling Highways England to use it in surveys, focus groups and other customer consultations for the widest range of stakeholders. The method for using CLeMM is described in the CLeMM Guide
Effect of Gravel Size and Weir Height on Flow Properties of Gabions
لقد تم دراست العلاقة بين عمق الماء المتجمع امام السداد الحجرية والتصريف القادم من اعالي المجاري المائية في قناة مختبرية. حيث تم دراسة السطح الحر للماء في حالة التدفق الانتقالي وفي حالة الفيضان فوقه. تضمنت الدراسة تأثير ارتفاع جسم السداد الحجرية وخشونة المواد المستخدمه في الانشاء على عمق تدفق المنبع عن طريق اختبار أربعة ارتفاعات مختلفة من الهدارات وأربعة أحجام مختلفة من الحصى. أظهر تحليل النتائج المختبرية أن الانخفاض النسبي في عمق الماء المتجمع امام الهدارات يتراوح ما بين 38٪ و17٪ لنوع الجريان " التدفق خلال " عندما يزداد كل من خشونة المادة والتصريف، وفي نظام "التدفق الانتقالي"، تؤدي زيادة خشونة المواد والتصريف إلى انخفاض متوسط في عمق التدفق النسبي بين 7.6٪ و4.4٪ لارتفاع الهدارات الحجرية 15 سم و30 سم، على التوالي. يبدأ السداد الجرية في العمل كهدار يفيض الماء من فوقه عندما يكون متوسط عمق الماء إلى ارتفاع السداد (H / P) هو 1.19، في حين أن متوسط الزيادة الإجمالية في التصريف نسبة إلى تصريف السد الصلب هو 15 ٪. كما تم أقتراح علاقات تجريبية للتنبؤ بعمق الماء المتجمع أمام السداد الحجرية لكل من أنظمة التدفق الثلاثة. كما تم اقتراح علاقة تجريبية عديمة الابعاد للتنبؤ بمعامل التصريف لهذة السداد وبدقة جيدة.The variation between flow depth generated in front of gabion barrier and flow rate has been studied in open laboratory flume. Flow profiles have been observed for each of "Transition Flow" and "Overflow" regimes. Effects of gabion height and material coarseness on the upstream flow depth are studied by testing four different gabion heights and four different medium aggregate sizes. The analysis of experimental results showed that the relative decrease in flow depth varies between 38% and 17% for "Through Flow" type when material coarseness and discharge increase. In "Transition Flow" regime, increasing material coarseness and discharge causes an average decreases in relative flow depth of 7.6% and 4.4% for gabion heights 15cm and 30cm, respectively. Gabion begins to operate as an overflow weir when the average water depth to the gabion height (H/P) is 1.19. While the overall average increase in discharge relative to solid weir is 15%. Prediction relationships for flow depth upstream the gabion for each of the three flow regimes is suggested. Also, dimensionless relation to predict discharge coefficient are proposed with good accuracy
Properties of Flow through and over Gravel Basket Weir
يؤدي إنشاء هدارات من سلال الحصى في المجاري المائية إلى تراكم المياه أمام هذه المشأت المسامية، ويكون فيها منسوب المياه أقل من تلك التي تتجمع مقدمة الهدارات الصلبة. تتضمن هذه الدراسة، تقديرعمق الماء المتجمع امام هذه الهدارات مع قياس شكل السطح الحر للجريان والتنبؤ بقيمة معامل التصريف من خلال التجارب المختبرية. كما تمت دراسة أربعة أطوال مختلفة من الهدارات (15 ، 20 ، 25 و 30 سم) وأربع خشونات مختلفة من الحصى (1.13 ، 1.58 ، 2.19 و 2.27). وفقًا لذلك، فقد تم اختبارستة عشر نموذجاً في ظروف مختلفة من التدفق الحر. أظهرتحليل نتائج نظام الجريان "التدفق النافذ" أن الزيادة في عرض السد تسبب في زيادة عمق الماء المتجمع امام الهدارات ولجميع درجات الخشونة بنسبة 30٪ بينما تقلل الخشونة من العمق بنسبة 28٪. وفي "التدفق الانتقالي"، يؤدي مضاعفة الطول إلى زيادة عمق التدفق بنسبة 7٪، بينما تؤدي زيادة الخشونة من 1.13 إلى 2.72 سم في انخفاض عمق الجريان بنسبة 7٪. يبدأ نظام "التدفق الفائض" بالظهورعندما تساوي نسبة عمق الماء إلى عرض السد حوالي 0.75 للعرض الكبير و1.54 للعرض القليل. تشير المقارنة بين هدارات سلال الحصى والهدارات الصلبة إلى أن متوسط تقليل عمق الماء هو 7.5٪ للصلابة البالغة 1.13 سم و9٪ للصلابة البالغة 2.72 سم. تم اقتراح نماذج رياضية للتنبؤ بعمق المياه لأنظمة التدفق الثلاثة، أما بالنسبة لنظام "التدفق الفائض"، فقد اقتُرِحَت صيغة تجريبية لتقدير معامل التصريف بدقة مقبولة.Construction of gravel basket weir in waterways causes water accumulation in front of this porous structure less than solid weir. In the present study the upstream flow depth, water surface profile and discharge coefficient are investigated through laboratory experiments. Four different weir lengths (15, 20, 25 and 30 cm) and four different degrees of gravel coarseness (1.13, 1.58, 2.19 and 2.27) are studied. Accordingly, sixteen models are tested under different free flow conditions. Analysis of the results show that in "through flow" regime the increase in weir length raises the generated upstream depth for all coarseness degrees by 30% while coarseness lowers the depth by 28%. In "transition flow", however, doubling the length increases the flow depth by 7%, but increasing coarseness from 1.13 to 2.72 cm mean diameter causes 7% reduction in flow depth. The "overflow" regime begins to appear when the depth to length ratio equals 0.75 for long weir, and about 1.54 for shortest weir. A comparison between gravel basket weir and corresponding solid weir indicates that average depth reduction is 7.5% for coarseness of 1.13 cm and 9% for coarseness of 2.72 cm. Mathematical models for water depth prediction for the three flow regimes are presented. For "overflow" an empirical formula is proposed to estimate the coefficient of discharge with acceptable accuracy
The concept of 'institutional waste within the construction industry': a potential theoretical framework
Question: Do imperfect institutional forces contribute to the generation and persistence of waste in construction projects?
Purpose: The ultimate purposes of this paper are to: (1) Contribute to the understanding of waste in construction by suggesting a new perspective on the generation and persistence of waste in construction projects; and (2) Shed light on a number of regulations, norms and routines, which are taken for granted and impede efficiency and improvement efforts in construction.
Research Method: The analysis of this paper is based on a critical literature review of theories of lean thinking, waste in construction and organizational sociology, in addition to industry experience and observation of co-authors.
Findings: This paper establishes the significance of considering the influence of the institutional context on the generation and persistence of waste in construction.
Research Limitations: This paper is conceptual and makes a case for further empirical research using neo-institutional theory – a branch of organisational sociology.
Originality/Implications: The concept of 'institutional waste within construction' offered within this study is novel and has the potential to deliver a theoretical framework that can be used for the prescriptive causal analysis of waste in construction, existing at the organisational, commercial and institutional levels.
Value to practitioners: The institutional perspective offered within this study highlights to practitioners the importance of thinking systemically and structurally. It could also enable clients and decision makers to consider the impact of institutional factors on the way they procure construction projects, and thus their desired project outcomes
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Exploring the implementation of the Last Planner® System through IGLC community: twenty one years of experience
The construction industry has, over a long period, been criticised for its short term “hit-and-run” relationships which are focused on win-lose situations and poor
performance. Despite the wide recognition of these problems the industry persistently resists the radical change demanded of it. This paper attempts to investigate why this
might be the case by reviewing prevailing safeguarding practices within the current commercial systems and structures through literature review and industry observation. Findings reveal that clients and decision makers often tend to safeguard their project specific
assets, against opportunism and exploitation, through the deployment of formal contractual arrangements and governance structures. These arrangements and
structures typically dominate the management of the project delivery often to the detriment of the project itself; but because there is a belief that interests are safeguarded, clients and decision makers feel they have taken the best course of action. This goes a long way to explaining the coherence of the current construction model and provides the basic information for preparing a route to the radical change required to move to lean methodologies
Finite Element Approach of Shielded, Suspended and Inverted Microstrip Lines
In this paper, we present finite element method (FEM) to investigate the electromagnetic analysis of two-dimensional (2D) shielded, suspended and inverted microstrip lines for microwave applications. In the proposed method, we specifically determine the values of capacitance per unit length, inductance per unit length, and characteristic impedance of the microstrip lines. Extensive simulation results are presented and some comparative results are given with other methods and found them to be in excellent agreement. We extend the analysis by designing our new model of shielded, inverted microstrip lines and compared it with shielded, suspended microstrip lines; we found them to be very close. Also, we determine the quasi-TEM spectral for the potential distribution of these microstrip lines
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Institutional waste within the UK construction industry: an exploratory study
The construction industry is often criticised for being wasteful compared to other industries, confrontational, and for lacking capacity for learning and improvement. Numerous industry reports have been commissioned by the United Kingdom (UK) Government and industry organisations, over the past eighty years, with the aim of highlighting concerns and calling for industry reform. In 2013, the UK Government challenged construction to achieve 50% faster delivery and a 33% reduction of clients' capital costs by 2025. In 2016, the Government Construction Strategy 2016-20 was produced with an ambition of achieving efficiency savings of £1.7 billion over the course of the current Parliament. It is however suggested that prevailing business models are unlikely to meet these targets.
Eliminating (process and physical) waste from construction design and delivery is a necessary step towards achieving the aforementioned targets. However, waste-reduction understood simply as the improvement of current processes rather than fundamental system redesign is insufficient. Obtaining a wider understanding and conceptualisation of waste in construction is crucial, in order to prepare the industry for the radical change demanded of it. This research was, thus, undertaken to explore the institutional, procurement and commercial environments surrounding the design and delivery of construction projects, and reveal the consequential wastes. A reflexive grounded-theory methodology was adopted to explore the institutional factors influencing construction procurement, and to facilitate an in-depth understanding of the impact of prevailing construction procurement arrangements on project performance and outcomes. Data were primarily collected through in-depth and iterative interviews with 24 senior professionals withinthe UK construction industry, including a review of supporting documentations provided by the interviewees.
Consequently, a conceptual model of 'institutional waste in construction' was developed by the author of this study, which was then evaluated by various UK industry experts to assess its quality and rigour. This model is a novel contribution to knowledge providing innovative perspectives to the generation and persistence of waste in construction projects. The model also provides novel explanations as to why wasteful procurement practices prevail in the construction industry. It is concluded by stressing that any industrywide initiatives for improvement (e.g. BIM and Partnering) will stall or at least fail, to achieve its full potential, unless the prevailing institutional factors, identified within this study, are addressed
Are Tier-one contractors making their money out of wasteful procurement arrangements?
The UK Government challenged construction to achieve 50% faster delivery and a 33% reduction of clients' capital costs by 2025 – prevailing business models won't meet these targets. Eliminating waste from construction design and delivery as advocated by lean ideals is therefore a necessary step towards these goals. However, waste understood simply as the improvement of current processes rather than fundamental system redesign will not be enough. Obtaining a better understanding and conceptualisation of waste in construction is therefore becoming more crucial. One aspect of this is to challenge the apparent coherence of prevailing procurement practices generated by the institutional, organisational, and commercial environments that surround the design and delivery of construction projects. This paper contributes to this by examining Tier 1 contractors and presents examples of practices that open debate on how to challenge prevailing procurement models for construction. Through literature review and interviews, the study discusses the factors influencing the ‘Principal-Agent’ relationship demonstrating how procurement arrangements often mirror institutional forces. These forces do not necessarily guarantee better value services, they are more likely to serve the interests of large industry players with the bargaining power to create new rules (North, 1994). A radically different delivery model, where the client intends to eliminate the management fees and confrontational behaviours of their Tier 1 contractors is described
Effect of Prismatic Sill on the Performance of Free Flow under Sluice Gate
Sills under sluice gates is used in hydraulic structures; their effect on the head generated upstream gates for certain rate of flow is related to the height and length of sill. A study is held in laboratory flume on four different prismatic sill heights and one model without sill by changing the gate opening four times for each model. Statistical analyses on the dimensionless physical quantities are done. A positive effect of sill on the performance of flow is noted by increasing the flow rate up to 25% for some models. The coefficient of discharge decreases with increase of relative sill height to the head upstream and increases with three other dimensionless parameters. The relative sill height to the gate opening shows the highest correlation factor with the discharge coefficient and its positive effect on the flow phenomena is 55.4%. Within the experimental measures limitations, a linear equation for predicting the discharge coefficient is proposed with Adj. R2 0.923
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