Calibration 7" – Cutthroat Flume as New Size for Discharge Measurement at Free Flow Condition

This paper aims to conduct a series of laboratory experiments in case of steady-state flow for the new size 7 ̋ throat width (not presented before) of the cutthroat flume. For this size, five different lengths were adopted 0.535, 0.46, 0.40, 0.325 and 0.27m these lengths were adopted based on the limitations of the available flume. The experimental program has been followed to investigate the hydraulic characteristic and introducing the calibrated formula for free flow application within the discharge ranged between 0.006 and 0.025 m3/s. The calibration result showed that, under suitable operation conditions, the suggested empirical formulas can accurately predict the values of discharge within an error ± 3%

Field and Satellite Images-Based Investigation of Rivers Morphological Aspects

Worldwide and especially in less developed regions, process-based evaluations and/or geomorphological information on large-scale rivers are still scarce. Such investigation become of ‎urgent ‎need due to the climate change and expected occurrence of extreme floods and drought which ‎may ‎threaten the safety of nearby and downstream cities, especially in regions that are highly sensitive and ‎affected by climatic changes. The Tigris River, in Iraq, is one such river that has undergone significant alteration to its flow and morphologic aspects due to climate change and the construction of many dams. However, morphology and its change for many reaches of this river are still uninvestigated. To this end, field and satellite-based investigations into the morphology of a reach located between Makhool District and Tikrit City have been conducted. In addition to the cross-sectional survey-based determination of the reach geometrical aspects, a sinuosity indices-based evaluation of the reach planform was implemented, utilizing a satellite indices-based approach. Furthermore, the characteristics of bed material were identified through field sampling. Investigation results show that the reach has a steep bed slope and many islands of low altitude with an elongated shape. The reach has a mild sinuosity with alternating bars. The dominant particle sizes of the bed material are coarse and medium gravel with a dominant particle shape of disc particles. Moreover, the satellite-based change detection indicated the fading out and disappearance of some secondary channels, the growth of many islands, and the movement of some bends downstream. The percentage of changing parts for the period 1975–2021 is 14%. Most of this change, 11%, occurred after the construction of the Mosul Dam. This reveals the sensitivity of reach morphology to flow change due to the construction of dams. The conducted fieldwork and the applied methodology contribute to supporting efforts to add knowledge worldwide about uninvestigated rivers. Doi: 10.28991/CEJ-2022-08-07-03 Full Text: PD

Monitoring and Modelling Morphological Changes in Rivers Using RS and GIS Techniques

River geomorphological investigation issues have received little attention in most countries of the world. Such processes become a pressing necessity due to climate change and anticipated events of extraordinary surges and dry seasons, which may debilitate the security of adjacent and downstream cities, particularly in locales that are exceedingly delicate and influenced by climatic changes. Al-Abbasia reach is a river that runs through the middle of the Euphrates River and is known for its numerous bends and meanders. The study of hydraulic structures such as barrages can provide important information about their influences on morphological processes in river reaches near the barrage upstream and downstream. Hydraulic analysis is made of the river behavior in u/s and d/s of hydraulic structures like barrages as a result of sediment deposition and erosion in u/s and d/s. A study, i.e., research on the impacts of the Abbassia barrage on the river system, has been conducted to address this issue using multi-temporal Landsat satellite data from 1976 to 2022 provided by the USGS. The study reach is located 5 kilometres upstream and 5 kilometres downstream of the Abbassia reach. Following the construction of the barrage, which had an impact on the sedimentation and geometry of the river, morphological variations took place in this part of the Al Abbassia reach. In this study, morphological changes throughout 49 years between 1976 and 2022 were investigated utilising remote sensing (RS) and geographic information system (GIS) approaches. Additionally, four image groups from three separate decades were used to perform change detection (1990–2000, 2000–2010, and 2010–2022). In this study, a monitoring system using Landsat-3 MSS: 1985, Landsat-5 TM: 1990, 1995, 2000, 2005, and Landsat-8 OLI: 2010, 2011, 2015, 2021, 2022 were employed to map river planform changes. The long-term comparison of this series of satellite images and historical maps for the period 1976–2022 indicates a continuation of change in the reach study with a rate of approximately 56, 33, 97, and 55% for upstream and 19%, 26%, 3%, and 45% for downstream for the width, area, deposition, and erosion, respectively. Furthermore, it is observed that there is a shift in river course within 200 m downstream of the barrage for the period of 1985–1990. The findings of this study, which monitor river morphological change at finer temporal and spatial resolutions, are crucial for promoting sustainable river management. They also aid in the investigation of river behaviour, which is necessary for providing the best management possible and overcoming the difficulties posed by this important research issue. Doi: 10.28991/CEJ-2023-09-03-03 Full Text: PD

Hydraulic Performance of Abrupt Expansion Transition with a Semi-Circular Dispenser

The eddies that result from the flow separation in abrupt expansion transition structures lead to serious problems in the bed and sides of the downstream channel. The head loss produced through expansion, on the other hand, is important as it affects the downstream stage. This study aimed to develop the hydraulic performance of an abrupt outlet transition at subcritical flow. Keeping the head losses at lower stages, and achieving near-uniform velocity distribution in the transverse direction by spreading the flow laterally, are the aims of this study. A new baffle column model that has not been previously investigated was adopted and installed into a sudden transition to work as a dispenser of extrusion inside the transition. This model is semi-circular in shape with the convex against the flow, by which the flow spreads and distributes across the width with increased uniformity. At the same time, this shape keeps the head losses at a minimum. The results of this attempt prove that it has considerable advantages both hydraulically and economically over using a flared wall transition. The results indicated increased uniform distribution of local velocity across the width, shorter length, and no more head loss than occurs at plain abrupt transition

Experimental Study of Coupled Parabolic Weir over Flow and Gate under Flow Rate

A combined flow through composite hydraulic structure or device represents a very important problem as a result of the interaction between over flow rate and under flow rate. In the present study, many experiments were implemented in the hydraulic laboratory considering several variables such as hydraulic variables and geometrical variables to investigate the overlapping between weir and gate having a parabolic shape. It is found that the weir and gate cross sectional area of flow have significant effect on coefficient of discharge of combined hydraulic structure. It is also very necessary to take the effect of geometrical parameter and the parameter expressed in this study in terms of ratio (y/H). This ratio has a primary effect on discharge coefficient. This study indicates that the overlapping between flow velocity of weir and gate respectively is central to value of discharge coefficient. This study mentions the effect of viscosity on coefficient of discharge in terms of Reynold number. Also, this study proves that the parabolic shape more efficiency as compare with regular shape. Keyword: Parabolic weir, Parabolic gate, Composite hydraulic structure, Flume

Evaluation of the Hydraulic Performance Indicators for Al- Ibrahim Irrigation Canal in the South of Iraq

This study was concerned for steady flow in open canals of different flow conditions that may exist in irrigation system. To achieve this objective, AL-Ibrahim Canal Located South of Iraq has been selected from numerous irrigation systems having deficiencies between demand requirements and actual supply, due to a problematic of distribution and management. The field works consists the measurements of stages at outlets,at upstream, and at downstream head regulators .The study adopted nineteen actual cases of discharge along six months, two or more measurements at each month during the study period,between November 2013 to April 2014.The main objectives of the present study are; analysis the actual operation of irrigation canal and evaluated indicators then the HEC-RAS model was applied to achieve these objectives. Themax. stage and discharges measurements at head regulator during the study period was4.415 m3/sec at Jan.2014,where it less than a target discharge , so the outlets along canal should not be operated at the same time especially if the gate of the outlets are fully opened , because for entire operation numerous outlets will take discharge higher than the target.The study has shown that it doesn'toperatethe channel and access to the standard of performance but several scenarios have been prepared depending on the discharge at head regulator

Experimental Study of Hydraulic Response for Combined Weir-Gate Flow of Composite Shape

Composite hydraulic structures play a vital role in controlling the flow in the irrigation system because of the interaction between over flow velocity from weir and under flow velocity from gate and this interaction will reflect on hydraulic response of structure. In the present work, numerous experiments were carried out in the laboratory of hydraulic engineering considering many variables that have direct contact in flow interaction and these variables are divided into two parts: the first is non-dimensional variable such as coefficient of discharge, Reynolds number and Froude number. The second is dimensional variable flow-rate and water depth above weir. These variables are considered for both upstream and downstream of the flume respectively and for different tested models of composite device. This study reviews that the flow velocity and the flow depth of water above the weir have major effect on hydraulic response in upstream and downstream of the flume respectively. The hydraulic response express in term of non-dimensional variable and dimensional variable. Keywords: Composite hydraulic structure, Composite device, Froude number, Reynolds numbe

Relevant Problem of a Hydraulic Jump at Diyala Weir and the Proposed Remedy

This study aims to analyze the Diyala weir problems and compares it with the safe limit and proposes the treatment for these problems. One of the most influencing problems in the site of weir was the formation of the hydraulic jump, it was found that the scour occurs due to the position of the hydraulic jump and the sequence depth of the jump is higher than the tail water depth. Some treatment procedures are suggested, these treatments cover this problem by presenting a suitable stilling basin as well as recommended to use a low weir at end of basin to produce a back water curve that should be increase the stage of tail water and ensuring the stability of a hydraulic jump

Bioactive Constituents of Juniperus turbinata Gussone from La Maddalena Archipelago

A comprehensive phytochemical study of Juniperus turbinata (Cupressaceae) collected from La Maddalena Archipelago (Sardinia, Italy) is reported. Both the essential oil and the ethanolic extract obtained from the aerial parts were analyzed. The essential oil appears to belong to a new chemotype compared to other Mediterranean juniper accessions, as it was favored by geographic isolation of the isles. It showed a low content of monoterpene hydrocarbons and a-terpineol, entmanoyl oxide, 1,10-di-epi-cubenol as the major constituents. The ethanolic fraction contained mainly diterpenoids. Among these, 15-formyloxyimbricatolic acid (7) is a new natural product since it has hitherto been obtained only by synthetic route. The phenolic fraction contained biflavonoids: cupressuflavone (9), followed by minor amounts of amentoflavone (10) and hinokiflavone (11). The essential oil and six purified compounds (1 – 4, 8 and 9) were assessed for biological activities, namely antioxidant (assessed by DPPH·, ABTS· + and FRAP methods) and cytotoxic effects towards selected human tumor cell lines (MDA-MB 231, A375 and HCT116 cells). Compound 3 exhibited higher radical scavenging activity against ABTS·+ radical than the reference Trolox. Noteworthy, compound 8 showed powerful effects towards tumor cell lines, with IC50 values in the range of 0.060 – 0.201 lM, which make it a promising anticancer drug candidate

Terpenoid biotransformations by Mucor species

Terpenoids are natural products of great interest due to their widespread use in agrochemicals, drugs, fragrances, flavouring and pigments. Biocatalysts are increasingly being used in the search for new derivatives with improved properties especially to obtain structurally novel leads for new drugs which are difficult to obtain using conventional organic chemical methods. This review, covering up to the end of 2012, reports on the application of Mucor species as catalysts in terpenoid biotransformation to obtain new drug targets, enhance pharmacological activity or decrease the unwanted effects of starting material