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

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

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

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

Evaluación del rendimiento de los métodos de iteración de listas en Java: un estudio empírico

Introduction: Lists are used in various software applications including web applications, desktop applications, and Internet ofThings (IoT) applications to store different types of items (e.g.country name, product model, and device category). Users can select one or more of these items to perform specific tasks such asfilling forms, ordering products, reading device data, etc. In somesoftware applications, lists store a huge number of items to be iterated over in order to know what users have selected. From a software development perspective, there are a number of methods toiterate over list items. Materials and Methods: In this paper, fivelist iteration methods: Classic For, Enhanced For, Iterator, List Iterator, and For Each have been compared experimentally with eachother with regard to their performance (execution time required toiterate over list items). Thus, a number of experimental test scenarios have been conducted to obtain the comparison results. Resultsand Discussion: The experimental results of this study have beenpresented in Table 4. Conclusions: Overall performance evaluation showed that Iterator and List Iterator methods outperformedother list iteration methods in all test scenarios. However, List Iterator outperformed Iterator when the list size was small. On theother hand, Iterator outperformed List Iterator when the list sizewas large

Turmeric dyeing and chitosan/titanium dioxide nanoparticle colloid finishing of cotton fabric

The possibility of combining the finishing and natural dyeing of cotton fabric has been studied using a single-stage, paddry-cure technique, by treating it with chitosan/titanium dioxide nanoparticle colloids and turmeric dye. Differentparameters have been studied to optimise the process, such as the chitosan/TiO2 nanoparticle colloid concentration, citricacid crosslinker concentration, sodium pyrophosphate catalyst concentration, dye concentration, pH, curing time, andtemperature. To investigate the effects of combined treatment on the dyeing and functional properties of the treated cottonfabric, its ultraviolet protection factor, antibacterial activity, self-cleaning properties, rigidity, colour strength (K/S), fastnessbehaviour, nitrogen content, and wettability are determined. In addition, the cotton fabric surface is characterised usingscanning electron microscopy. The samples treated with chitosan/TiO2 in the presence of citric acid exhibit excellentprotection against ultraviolet radiation as well as antibacterial activity. The optimum conditions are 0.75% TiO2 (w/v), 10% dye (w/v), 2.5% chitosan (w/v), 30 g/L citric acid, 4 g/L sodium pyrophosphate, 70°C drying temp. and 5 min drying time,180°C curing temp. and 2 min curing time. The results also indicate the efficiency of the treatment in improving the selfcleaningproperties of the fabric. A significant improvement in the colour fastness is observed for the treated fabrics

Statistical Analysis of VoDSL Technology for the Efficiency of Listening Quality of 640k/640k

Next-generation Internet technology will offer high performance and high capacity traffic aggregation and scalability. Voice over Digital Subscriber Line (VoDSL) technology allows service providers to offer multiple telephone lines over a single subscriber line in addition to high speed data transmission services. This article provides a baseline test for the Listening Quality (LQ) using VoDSL access technology by using Voice/Listening Quality (V/LQ) transmission with voice compression while countinously downloading files. The result will be to enable the efficiency of the LQ and its statistical analysis based on a Digital Subscriber Line (DSL) service at level 640K/640K for each American National Standards Institute (ANSI) and Carrier Serving Area (CSA) loops

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