bluuebunny/crossref_metadata_2025 huggingface dataset:
Parametric architecture: the second international style
Authors: Al-Azzawi T , Al-Majidi Z
Published: March 2021

Parametric architecture (parametric design) emerged as a concept or theoretical idea in the world of architecture around 2008, in parallel with the development of digital design tools and the rise of the new communication technologies that have spread widely in recent years, supported by the digital revolution. Many research attempts have thus been made to deal with parametric design, with interest focusing both on defining it as a philosophical and theoretical concept in contemporary architecture and as a new architectural style with specific characteristics; it may also be considered an architectural movement, or a set of techniques for the production of form at the design and implementation levels. Many attempts have also been made to define it in order to promote teamwork through collaboration between architects and other engineering specialists during the design process. This paper discusses the possibility of achieving multiple such goals by defining the notion of parametric architecture; the research problem is thus the lack of clarity of the concept or the idea of the style in terms of formal characteristics as a result of over-rapid adoption of the methods and techniques of parametric design. The research aim is to discover and explain this idea more fully, demonstrating its difference from conventional concepts of style, by comparing it with the concept of the international style that emerged based on modern architecture theories, techniques and methods during the first half of the twentieth century. To achieve this, the paper presents a set of global experiences illustrating the use of digital design technologies in different stages of production, highlighting the final characteristics of the products and what they have in common. Schumacher’s dogmas and the taboo principles were thus adopted in an attempt to develop this comparison with the international style that emerged from the theories and implementations of modern architecture, and to investigate the role of modern technologies in producing its forms. The paper ends with a general conclusion that demonstrates the possibility of presenting parametric architecture and its products globally as a second international style, though currently in the stage of formation, as its fundamental principles are based on the idea of renewal and revolutionary rejection of all that has preceded it; thus, the repetition of these attempts results from dealing with the same theoretical principles and standards imposed by the techniques that produced the contemporary architectural form.
An investigation of the relationship between surface albedo and urban cover types in a semi-arid region
Authors: Hamoodi Mustafa N , Mahdi Zainab R
Published: March 2021

Surface albedo, is a key parameter controlling the local energy budget, which in turn plays an important role in mitigating the effect of urban heat islands. This paper aimed to examine the relationship of surface albedo to major land cover categories, which include built-up areas, green covers, water bodies, and bare land. This study provides a new approach by using a 30 m spatial resolution of Landsat data over the study area, Baghdad, and relating surface albedo to the metrics of four biophysical parameters: Normalised Difference Vegetation Index (NDVI), Modified Normalised Difference Water Index (MNDWI), Normalised Difference Build-up Index (NDBI) and Normalised Difference Barren Index (NDBaI). A linear regression was generated to assess the correlation of surface albedo with these four biophysical parameters, and the results showed a strong positive correlation between surface albedo and both NDBI, and the NDBal (r = 0.62 and r = 0.95, respectively), and a moderate correlation with NDVI (r = 0.4). There was also a strong negative correlation of surface albedo with MNDWI (r = – 0.81).
Utilisation of Dune Sand and Clay Brick Waste in the Production of Sustainable Concrete
Authors: Zemam Sajid Kamil , Abed Musab Sabah , Resan Sa’ad Fahad
Published: March 2021

The massive growth of the construction sector has increased demand for sustainable concrete that meets the requirements of modern eco-friendly policies; this in turn has made it necessary to reuse abundant and recycled materials to achieve this end. In this study, crushed clay brick (CCB) as a coarse aggregate and dune sand (DS) as a fine aggregate were used to produce a sustainable concrete. An experimental programme was accomplished by performing partial replacement by DS of conventional sand (CS) at various percentages (25%, 35%, and 50%), with a similar procedure used for crushed clay brick (CCB) and conventional coarse aggregate (CA). The impact of this dual aggregate replacement on workability, density, tensile splitting, and compressive strength was then studied, and the experimental results showed that the density decreased by 12.3% as the dual replacement of aggregates increased to 50%. The workability of the sustainable concrete was within the standard limits, while the results of the slump tests ranged between 120 mm for control concrete and 80 mm as the dual replacement of aggregates increased to 50%. Both the splitting and compressive strengths of the produced concretes were systematically decreased as the dual replacement of aggregates increased under 7- and 28-days curing. The produced concrete was thus deemed to be generally affordable though suitable only for general small works or non-structural uses.
Experimental and Numerical Investigation of Composite Girders with Thin Corrugated Webs
Authors: Dhafer M. H. , Muteb Haitham H. , Kadhim Mustafa Amoori
Published: March 2021

The capacity of composite girders may depend on their web stability; thus, webs could be reinforced with stiffeners or corrugated shapes adopted to increase such stability. Developing on two previous techniques, a corrugated shape was used in a new pattern, similar to a transverse stiffener, to increase the flexural rigidity of the plate, causing the shear stability of the webs to increase. Three composite girders were manufactured using the new pattern of corrugated web and tested under static loading. The results showed that the girders with corrugated shapes had different behaviours to girders with flat webs. The examination of a composite girder with a deck slab of UHPC also revealed that the deck slab worked with the web to resist the shear stress, suggesting that the corrugated technique could be used as an alternative to reinforcing the web, especially in composite girders. This technique increased the shear strength capacity by about 44% over that of flat web composite girders. All composites failed due to the web buckling, without crushing or cracking of the UHPC deck, where the normalised shear reached 0.7 of the yield shear stress for the corrugated web. Finite element analysis using ABAQUS software was performed, which showed reasonable agreement between results and enabled the study of additional parameters without combination factors.
Behaviours of reinforced concrete slabs under static loads and high-mass low velocity impact loads
Authors: Said A I , Mouwainea E M
Published: March 2021

This paper examines a progression of experimental studies designed to investigate the response of reinforced concrete slabs subjected to static and high-mass low-velocity impact loads. A total of ten reinforced concrete slabs were tested: three specimens were tested under static load by loading the specimens at their mid-point, and seven specimens were tested under impact load to research the high-mass, low-velocity impact behaviours of reinforced concrete slabs using a drop-weight facility. Measurements methods included a load cell, acceleration, strain in the reinforcement steel and a laser sensor to measure deflection in the centre and various quarters of the slabs (LVDT). The experimental variables included in this study focused mainly on the thickness of slab under static and impact loads, the mass of the striking object, and the height of the striking object for impact loads.

The results showed that under static loads, the mean of the thickness of the slab increased by 33 to 100%, the maximum deflection at the central point decreased by 45 to 63 %, and the load capacity of the slabs increased by 77 to 265%. With respect to high-mass low-velocity impact loads, as the slab thickness increase by 33to 100%, the maximum deflection at the centre of the slabs decreased by 47.7 to 84 % and the impact force increased by 37.5 to 102%. When the height of the striking object was increased by 33 to 66%, the maximum central deflection of the slabs also increased by 24 to 72.3%, and the impact loads increased by 11 to 23.3%. Increases in the mass of the striking object by 50 to 100% led to the maximum central deflection of the slabs increasing by about 54 to 122% and to the impact loads increasing by 13 to 18.6%.
The effectiveness of ARIMAX model for prediction of summer rainfall in northwest Western Australia
Authors: Islam F , Imteaz M A
Published: March 2021

Inherent climate mechanism plays a large role in Australian rainfall events, while most interestingly, such influence of climate drivers on rainfall generation depends largely on a place’s geographical location and the season it has been passing through. For Northwest Western Australia (NWWA), summer has been the main rainfall season; therefore, it became necessary to develop a seasonal forecast model several months ahead of the event. This study involves the selection of potential climate drivers for NWWA and using them to forecast and model long-term seasonal summer rainfall (Dec to Feb) several months advance. Two rainfall stations (Bidyadanga and Gogo) were selected considering the availability of continuous monthly rainfall data (from 1915 to 2015) with a minimal missing value. Simple multiple linear regression (MLR) and ARIMAX have been performed on acquired rainfall data and lagged climate indices. It has been observed that the Southern Oscillation Index (SOI) and the Western Indian Ocean Index (WIO) has a great influence on NWWA rainfall. As such, the WIO-SOI model (4 months advance) shows a significantly higher correlation in the ARIMAX model (0.68 and 0.65 for Bidyadanga and Gogo station, respectively) compared to the MLR model (0.35 and 0.36) and confirms its effectiveness to be used for rainfall prediction in the region. It is believed that the simple but effective nature of the developed models can produce optimum benefit on stakeholder’s decision making to tackle future socio-economic challenges.
Application of wavelet artificial neural networks in forecasting seasonal rainfall time series in Queensland, Australia
Authors: Ghamariadyan M , Imteaz M A
Published: March 2021

Predicting accurate future rainfall plays an essential role in managing the water resources as well as controlling the unforeseen phenomena like flooding or drought. In this study, an Artificial Intelligence (AI) method called wavelet artificial neural network is used to predict one-year ahead seasonal rainfall of Queensland, Australia. The technique used in this study is based on wavelet transform and artificial neural networks (ANN). Over the wavelet transforms analysis, the primary signal is split into some sub-time series called approximation and detail. The outcome of this process is some meticulous and valuable information that cannot be easily captured in the main time series. To assessment the skillfulness of the proposed method, five input sets combined of rainfall and three climate indices are defined. The comparisons showed that the wavelet-ANN (WANN) presented the lower root-mean-square-error (RMSE) with 64.8mm compared to ANN with 88.9mm, and it outperforms the ANN forecast with respect to statistical measures. Since fewer data in predicting seasonal rainfall is available compared to monthly rainfall data, the application of WANN provides promising insights into using this AI method for predicting seasonal rainfall one year in advance in Australia.
Nanotechnology use to preserve the durability of archaeological brick buildings in Al-Najaf city
Authors: Alhilo E A , Kuba S A , Dirweesh A F
Published: March 2021

Archaeological buildings constitute the urban core of historical cities, supporting both private identity and urban life in society. Old Najaf city may be the most important city in Iraq due to its religious and spiritual value in the Islamic world; its archaeologic buildings thus represent the features of both collective memory and the private reality of cultural heritage. This research aims to achieve examine the use of nanomaterials in terms of contributing to the preservation of archaeological buildings built with bricks in Najaf City in particular, and Iraq in general, helping determine how to use these to prolong the life of these buildings based on the assumption that certain nanomaterials can prevent harmful environmental factors from affecting such buildings or causing further damage. This would allow a high level of environmental efficiency and help to perpetuate these historic buildings, as such treatments do not cause any changes in the original physical or chemical properties of heritage buildings. The study results suggest that Nano-treated bricks can effectively be used as a new building material for additive parts used to support archaeological buildings, thus offering access to buildings with high environmental efficiency.
Performance of Lime-Treated Sandy Soils after Sustainable Reinforcement Using Waste Plastic Fibre
Authors: Hameed Amjaad , Shaban Alaa M. , Almuhanna Raid R.
Published: March 2021

Subgrade soil is a natural formation utilised as a foundation for pavement layers, which means that it must be strong enough to support the pavement system. Subgrades such as loose sand, clay and silt soils thus need to be stabilised in order to improve in-situ performance. Several different geotechnical techniques have been utilised for soil stabilisation, and in this research, experimental work was carried out to examine the use of hydrated lime and waste plastic fibre as sustainable additives to enhance the characteristics of loose subgrade sand. The hydrated lime was added at several different percentages (4, 6, 8, and 10% by dry weight of soil), and the laboratory tests results revealed that adding 8% lime to the soil provided the best strength characteristics. The optimum lime-treated sandy soil was then reinforced by the addition of waste plastic fibre with lengths ranging from 5 to 20 cm added at three percentages (1, 2 and 3% by dry weight of soil). The dynamic behaviours of the reinforced stabilised soil in terms of surface deflection and dynamic modulus were evaluated using a light weight deflectometer test (LWD). The results illustrated that adding 10 cm waste plastic fibre at 3 wt.% content led to an increase in the dynamic modulus of 28.12% and a decrease in the surface deflection of 21.35% as compared to natural subgrade soil.
Numerical Study for Steel Arch Beams of Compact Section with Circular Web Openings
Authors: Hemzah Sadjad A , Abdul Rasoul Zainab M R , Naser Zahraa A
Published: March 2021

This study presents a numerical simulation of the behaviours of compact steel arch beams, with and without openings, using the commercial finite element software ABAQUS. Numerical model was firstly validated against under-publishing research to verify the accuracy of FEA results and then used to conduct a parametric study to investigate the effects of several parameters on the load - deflection curve of the arch steel beams with openings such as opening area, opening shape, openings number, yielding stress of steel material, radius of arch beam and effect of adding steel stiffeners. The results from the numerical investigation showed that the FEA results gave a good agreement with the experimental results in terms of ultimate strength, maximum deflection, load-deflection curves, and failure mode. The parametric study further showed that the ultimate failure loads for arch beams with openings decreased with the increase in the opening diameter from nearly 2 to 21% for openings of diameters 50mm and 125 mm, respectively, located at the centre of the web, while the ultimate load capacity of steel arch beams with edge openings decreased by about 26% in comparison with the control beam when the diameter increased to 125 mm. Also, the increase in the radius of the arch beam using radii of (537.3, 797.5, and ∞) mm resulted a decrease in ultimate load capacity about 17% and 40% for radii (797.5 and ∞ mm) respectively, compared with the control beam of radius 537.3 mm.
An experimental study of the load carrying capacity of straight shaft and underreamed piles in expansive soil
Authors: Ziyara H M , Albusoda B S
Published: March 2021

This research aimed to determine and evaluate the load carrying capacity of underreamed piles embedded in expansive soils. Eight models of concrete piles were developed to examine the influence of piles’ bulb number and length on ultimate load carrying capacity. The piles used in this work had 20 mm stem diameters and 40 mm bulb diameters, and multi-layer soils (expansive soil above dense sand) were used. The piles used in the experiments were divided into two groups, each with four piles. The first group with l/d=14 had all piles embedded in the expansive soil layer and the pile’s tip set on dense sand while the other group, with l/d=24, had the pile stems embedded in the expansive soil and all bulbs in the dense sand. Experiments were then done under two conditions: optimum moisture content and soil completely saturated with water, with results that showed that the percentage of ultimate load carrying capacity increased in proportion to the l/d ratio on adding one bulb to a straight shaft pile and then increased slowly for piles with 2 or 3 bulbs in saturation conditions. The percentage of ultimate load carrying capacity increased similarly in optimum moisture content conditions. The results also showed a decrease in ultimate load carrying capacity between the two conditions of tests for piles with the same l/d and the same number of bulbs, however.
Analysis and evaluation of a sewage network during heavy rains using the SSOAP toolbox
Authors: Nile Basim K , Mohammed Hussein Ali , Htif Khawlah A
Published: March 2021

One of the major problems facing urban areas is the recent increase in precipitation intensity over design standards due to global warming. This significantly increased precipitation depth directly influences sewage systems by causing increased flow and infiltration (RDII), which eventually leads to flooding of the systems. The aim of this study was to analyse and evaluate a sewage network during such severe rainfall, to determine the excess amount of rain entering the system. To achieve this, the Hay Al-Hurr region of Karbala was selected as a case study, and the Sanitary Sewer Overflow Analysis and Planning (SSOAP) toolbox was used to estimate the volumes of inflow and infiltration (RDII) entering the sewer network, while the stormwater management software (SWMM5) within the toolbox was used for hydraulic assessment of the sewage system. The sewage network of the main pipeline of the study area was analysed with regard to two rain events in 2016, one of which was a standard event of 25 mm, and the other a torrential event of 105 mm. The RDII was 2.29 mm for the first event and 2.58 mm for the second event; on calibrating these results with SWMM5, a display of flood areas for each event was created showing the percentage overflows for two events were 30% and 65%, respectively. These results were realistic and according to predictions, allowing the study to help improve engineering knowledge and decision-making capabilities with regard to designing sewage networks, as well as facilitating the development of appropriate solutions to rehabilitate those areas most vulnerable to standardised entry by developing specific strategies to reduce or eliminate the surplus runoff.
Experimental investigation into graphene’s effects on the mechanical properties of cement mortar under specific sonication parameters
Authors: Alagawani Besan , Ruan Dong
Published: March 2021

Graphene and its derivatives have been studied as nanomaterials in many different fields owing to their various interesting properties. Many researchers have investigated the mechanical properties of different graphene cementitious composites, and the current study investigates the effect on the mechanical properties of cement mortar of adding graphene with and without the use of an ultrasonic homogeniser. To examine this effect, all other testing conditions and requirements such as mix design content, mixing procedure, curing time, specimen size and sonication parameters were maintained at the same levels across tests. Cement mortar specimens containing different percentages of graphene (0, 0.003, 0.006, 0.009, 0.012 and 0.03% by weight of cement) were experimentally tested after 7 and 28 days to determine the effect of graphene dosage on their quasi-static strengths. The results showed an obvious enhancement in both compressive and flexural strengths after adding each graphene dosage to the mix without sonication; the compressive strength was increased by 12% with a 0.006% dose of graphene and the flexural strength was increased by 27% at a 0.009% dose of graphene. On using the sonicator at the specified parameters, the compressive strength increased by 33% for the 0.006% dose of graphene, offering an increment of 20% in strength due to the sonication effect; however, there was no noticeable effect on the flexural strength.
Impact behaviour of crushed-brick lightweight RC sandwich slabs
Authors: Abdul Sada Yasameen Azeez , Rasheed Laith Sh. , Al-Mahaidi Riadh
Published: March 2021

In recent construction practice, sandwich panels have been increasingly adopted due to the fact that they are lightweight, energy efficient, aesthetically attractive, and easy to handle and erect. This study examines the impact behaviour of lightweight reinforced concrete (RC) sandwich slabs produced from local lightweight coarse aggregate. The experimental program included testing two slabs produced with normal coarse aggregate (solid slab + sandwich slab) and six concrete sandwich slabs (CSSs) produced using crushed clay bricks as lightweight coarse aggregate with various shear connecter configurations and types and steel fibre volume fractions (VF%). The impact load was applied at the midpoint of each slab using an 8 kg drop-weight from a height of 2 m. The test results showed CSS behaviour variation with different VF% and the optimum layout and location of shear connectors.
Climate change risk assessment in Baghdad: examining population vulnerability
Authors: Abdulateef M F , Al-Alwan H A S
Published: March 2021

Studying climate change risks has acquired increased importance and attention around the world in recent years. Every city has its special points of strength and vulnerability that define its specific level of climate change risk. The assessment of this level offers multiple advantages by not just defining potentially impacted areas but also identifying the highest priority areas for the development of sustainable solutions. In Baghdad, surface urban heat island (SUHI) has been noted as one of the main climate change impacts, yet a review of the related literature suggested that few studies have previously assessed the risk level of SUHI, particularly in terms of population impacts in the Baghdad areas. Accordingly, this research aimed to classify the various Baghdad areas according to population exposure to SUHI risks, and to define the risk level as a result of the overlay and the intersection of two main factor layers, intensity of and vulnerability to climate change impact. The research results thus identified areas with the highest level of risk to populations, which thus represent the highest priority areas for any adaptation efforts. Conducting this assessment constitutes a basic step in defining sustainable future adaptation strategies, as well as identifying areas with lower levels of SUHI risk, where measures may be carefully taken to sustain and improve current environmental performance, allowing for a more long-term focus on environmental quality.
Punching shear strength of steel fibre reinforced concrete flat slabs: a literature review and design codes evaluation
Authors: Abbood Israa A. , Al-Bayati Ahmed Faleh
Published: March 2021

The design of reinforced concrete flat slabs is usually governed by their punching shear strength, and various methods have thus been suggested to increase the punching shear strength of flat slabs. Of these methods, the addition of steel fibre has proven to be among the most effective, not only in terms of enhancing punching shear capacity but also with regard to improving the ductility of flat slabs. This paper presents a comprehensive literature review of experimental investigations conducted to study the behaviour of steel fibre reinforced concrete (SFRC) flat slabs. In addition, the punching shear calculations of the ACI-318-19, the EC2, and the BS8110 codes were evaluated using the test results for SFRC flat slabs reported in the literature to determine their applicability in practice. These codes do not consider the strength contribution of steel fibres, and thus these comparisons with the test results revealed that the punching shear calculations of the above codes consistently underestimate the shear capacity of SFRC flat slabs.
Quantifying sustainability for two types of pavement based on life cycle cost and environmental impact
Authors: Al-Humeidawi Basim H , Chafat Osamah H
Published: March 2021

Several types of highway pavement have been adopted by various highway agencies, and each type has both advantages and disadvantages. Estimations of the life cycle cost and environmental impacts of pavement types have thus become major components of roadway planning, as the economic and environmental sustainability of pavements depends on both the project characteristics and the maintenance programme applied during the pavement life span. This article focuses on making a comparison of environmental impact in terms of Life Cycle Assessment (LCA) and Life Cycle Cost Analysis (LCCA) of two arterial streets in Al-Diwaniyah city centre. The first street utilises flexible pavement, while the second street is constructed with composite pavement layers, with a Hot Mix Asphalt (HMA) wearing layer implemented over a Portland Concrete Cement (PCC) pavement. The comparison between the streets was conducted using Athena Pavement LCA software, and the resulting analysis clarified the impact of pavement type, construction process and maintenance conditions on the environment in each case, taking into in consideration all related parameters such as material, construction processes, and the maintenance and rehabilitation programmes applied to the pavements during their life cycle. The results showed that the environmental impact in terms of gas emissions for the street implemented with flexible pavement was 48% higher than that of street implemented with a composite structure; further, the initial cost for the flexible structure was 17% higher that of pavement constructed with composite PCC and HMA. The LCCA for the street with flexible pavement was also 78% higher than that of composite structure due to the additional maintenance activities required during its service life.
Experimental and numerical analysis of axially loaded slender piles implementing a hypoplastic model
Authors: Subair A H , Aljorany A N
Published: March 2021

Multiple studies have been carried out to estimate uplift pile capacity, within three main categories: i) the experimental method, which is very costly; ii) a simpler method using load transfer mechanisms; and iii) the numerical finite element method (FEM). The predictive capacity of numerical simulation depends mainly on the constitutive model used to model the soil-structure interface at which the load transfers from the pile to the surrounding soil. A reliable constitutive model capable of capturing the main features of soil behaviour based on easily obtained parameters is thus required. The hypoplasticity model is a promising constitutive model in this respect, offering a particular class of rate non-linear constitutive model in which the stress increment is expressed in a tensorial equation as a function of strain increment, actual stress, and void ratio. The hypoplastic model thus requires only eight material parameters (critical friction angle φc
, e

c0, e

i0, e

d0 (critical, maximum, and minimum void ratios, respectively), granular stiffness hs, and the model constants n, α, and β), with two additional parameters used to simulate the pile-soil interface (kr
and

d
v
s

), which represent the surface roughness and the thickness of the shear zone, respectively. The performance of the model was verified in this work by comparing the numerical results with the experimental results for a single pile model under pull-out force with different surface roughnesses and confining pressures. The resulting good agreement between the numerical and the experimental results confirmed the ability of the hypoplastic model to simulate soil behaviour under complex conditions.
A study to improve plant layout design for minimizing production costs
Authors: Al-Bayati I I , Al-Zubaidy S S
Published: March 2021

Plant allocation and the costs of moving between workstations in production and manufacturing lines are among the most prominent factors affecting the total cost of production. Selecting appropriate work locations and distances between workstations is thus a key factor affecting the efficiency and productivity of a production line and thus the quality and cost of the final product. In this research, problems with a current plant layout are assessed with an eye to increasing productivity with minimum additional outlay. The aim is to improve the work flow in a pulley plant based on consequential planning of the plant layout, based on the assumption that the improved plant layout can reduce material flow distances, resulted in reduced costs of operation by about 5 to 10%.
An innovative mechanism for transmitting power from the pistons in internal combustion engines
Authors: Alnomani S N , Fadhel E Z , Hunain M B
Published: March 2021

Reciprocating internal combustion engines are common and thus important engines due to the many advantages they provide. Despite significant improvements being made to these types of engines in recent decades, however, they still suffer from low efficiency due to large losses in produced energy, which occur for multiple reasons. The crank mechanism is responsible for much of the observed energy loss, however.

In the current study, a new mechanism is suggested to transmit kinetic energy directly from the pistons, thus reducing energy losses associated with the crankshaft. This new mechanism eliminates the crankshaft from power transmission, limiting it to syncing piston movement. The pistons are then modified to mate with partial teething gears, which then transmit the kinetic energy directly from the pistons without this energy being negatively affected as it is by the angular position of the crank units. The testing results show that the power produced during the power stroke in the suggested engine is twice corresponding output of a classical engine.
Exploration of a plate heat exchanger utilising a phase change material: an experimental and computational study
Authors: Juaifer H J A , AbdulAmeer S A , Mahdi J A
Published: March 2021

In this article, the heat transfer mechanism of a phase change material (PCM) chamber during charging and discharging processes was studied both numerically and experimentally. A flat plate thermal storage system with dimensions of 500 × 100 × 12 mm, and a PCM thickness of 12 mm was thus investigated. The thermal storage material selected was commercial paraffin wax with a melting temperature of about 60 °C. A diffusion-advection numerical model was used to study heat transfer in this system, as it was observed that the experimental results were in good agreement with this model. In this way, natural convection was found to be the dominant phenomenon in the model. The effects of heat transfer fluid (HTF) temperature and volume flow rate on the melting and solidification time were also assessed, producing the finding that, by elevating the inlet HTF temperature from Th = 343 K to 348 K and then 353 K, the charging time can be reduced by up to 35%.
Uniaxial compression of bi-directionally graded lattice structures: Finite element modelling
Authors: Rodrigo C , Xu S , Durandet Y , Ruan D
Published: March 2021

Lattice structures are widely used in various engineering applications due to their high weight-to-strength ratio and exceptional energy absorbing performance. The feasibility of using different base materials to fabricate these cellular structures with complex geometries has been significantly broadened with the development of additive manufacturing technology. In this paper, quasi-static mechanical properties and energy absorption capability of polyamide PA 2200 (nylon 12) lattice structures were investigated by using finite element analysis (FEA) in ANSYS/LS-DYNA. Three types of lattice structures composed of body-centred cubic (BCC) unit cells were studied, including uniform lattice structures, uni-directionally graded lattice structures and bi-directionally graded structures. Finite element simulations were consistent with experimental data reported in literature. The results showed that bi-directionally graded lattice structures exhibited superior crushing resistance and higher energy absorption capacity than uniform and uni-directionally graded lattice structures. It showed that density grading design of lattice structures had significant influence on the deformation patterns and therefore, energy absorption performance.
Absorption characteristics of composite materials reinforced by zinc oxide nanoparticles and Kevlar fibres
Authors: Abed Z A , Rajab M A , Asfor A K
Published: March 2021

The research aims to study the effect of zinc oxide nanoparticles and Kevlar fibres on the absorption property of composite materials consisting of epoxy resins and phenol formaldehyde in different proportions. The results showed: Epoxy resins are not absorbed without adding phenol formaldehyde, which means an increase in the absorption property with an increases the proportion of phenol formaldehyde increases. The fibre strengthening also increases the absorption, so Kevlar with fibres gave the highest absorption; However, the absorption property decreases when the compounds are enhanced with zinc oxide nanoparticles as compared to the effects seen in the non-reinforced compounds.
Performance and exhaust emissions in a diesel engine fuelled with a blend including ZnO nanoparticles and nano-emulsions
Authors: Hamadi A S , Khudhur A G
Published: March 2021

A realisation of the need to curtail consumption of fossil fuels with high atmospheric emissions has led researchers to investigate alternatives in recent years. Nano-emulsions (NE) with water suspended at nano-size inside diesel fuel offer better air/fuel blends during the combustion process, creating fuels with higher combustion efficiency and lower emissions. For this study, a nano-emulsion with 12 W% was prepared in a high-speed homogenizer to produce an NE fuel with 26 nm effective droplet diameter, based on optimisation calculations in Design-Expert software. Three doses of zinc oxide (50, 100, and 150 ppm) with average diameters 10 to 30 nm were mixed into prepared nano-emulsion samples. Five fuel blends, Diesel, NE, NE+50 ppm ZnO, NE+100 ppm ZnO, and NE+150 ppm ZnO were then examined for performance and emissions in a four-cylinder Fiat Diesel engine at 1,500 rpm constant speed and 400 bar fuel injection pressure, with a changing operating load. Brake specific fuel consumption (BSFC) was reduced by 16.4% with an increase of 10.2% in thermal efficiency for NE+150 ppm ZnO in comparison with the neat diesel at higher loads of 352.88 kN/m2. CO, NOx, HC, and smoke opacity were also reduced by 18%, 13.2%, 17.1%, and 32.8 %, respectively for NE+150ppm ZnO. This research thus offer direction for the utilisation of ZnO nanoparticles in the reduction of exhaust emissions and fuel consumption, offering both economic and environmental benefits.
Investigating the impact of using nano-fluid as a cooling medium on photovoltaic/thermal panel system performance
Authors: Shahad H A , Abbood M H , Ali A A
Published: March 2021

Making use of the superior thermal properties of nanofluids is now very common, especially with regard to the cooling of photovoltaic panels to improve overall efficiency. In this work, a novel cooling system manufactured from 3 mm aluminium was attached to the rear of a monocrystalline photovoltaic module, and two volumetric concentrations of SiC/Water nanofluid were tested with different flow rates. These tests were carried out under outdoor climatic conditions in middle of Iraq at Babylon University (32.46 °N, 44.42°E) during both winter and summer. A theoretical model was thus developed in SolidWorks and simulated using ANSYS 18.2. The maximum enhancements in electrical and overall efficiency were found to be 50% and 82.41% in March with a 0.5% nanofluid concentration and 2 L/min flow rate, while the minimum enhancements were 35.4% and 34.01% in June, with a 0.1% nanofluid concentration and 0.5 L/min flow rate. The theoretical results showed good approximation to the experimental results, and the average deviation percentage of electrical efficiency for a photovoltaic/thermal system with nanofluid on 27 March was 5.58%, while on 3 June it was 11%.
Experimental and numerical evaluation of natural frequencies and mode shapes in a satellite model-plate connecting interface without vibration isolators
Authors: Dahham A W , Taranenko P A , Aljibory M W , Erpalov A V
Published: March 2021

This paper numerically and experimentally examines the natural frequencies and mode shapes in a satellite model-plate connecting interface installed on flexible gas-inflated jacks in order to assess the effect of external impacts on the natural frequencies of the satellite model and to thus generate a reference for appropriate vibration isolators for transportation and launch as required. The experimental determination of the frequencies and mode shapes of vibration in the system was carried out using modern software in conjunction with the hardware loading model satellite (LMS). Numerical calculation of the natural frequencies and mode shapes of the research object was performed in the finite element package ANSYS Workbench, with results suggesting that the suspension system (gas inflatable jacks) was sufficiently flexible and did not affect the natural frequencies at which the system under investigation, the satellite model-connecting interface plate, began to deform. Experimental determination of the natural frequencies and mode shapes of vibration for the satellite model-connecting interface plate was then conducted in the range from 44 Hz to 200 Hz; the differences in natural frequencies between the calculations and experiments averaged 10 to 15%.
Investigation of Harmonic Reduction Using Passive Filters in a Distribution Network in Basra City
Authors: Abood Salam B , Abdul-Wahhab Thamir M
Published: March 2021

Harmonics in current and voltage waveforms produced by nonlinear loads in a distribution system can be minimised using passive filters; however, implementing these filters requires the calculation of several suitable parameters for filter components. This work aimed to simulate and analyse the harmonics in the Al-Itihad 11 kV distribution system that branches off from Zubayr substation (33/11 kV) in Basra in Iraq using MATLAB/SIMULINK. Five non-linear loads were simulated to generate harmonics in the simulated Al-Itihad distribution system, and for each non-linear load three types of filters were tested: a single tuned filter (STF), double tuned filter (DTF), and C-type filter. The objectives of these filters to minimise the total harmonic distortion (THD) in the voltage and current waveforms, to minimise the total current, and to improve the power factor of the distribution system. The simulation results showed a reduction in total harmonic distortion, a reduction in the current at the main distribution feeder, and an improvement in the power factor of the feeder.
Optimal Reduction of electrical Loads Based on Priorities Developed Using a Genetic Algorithm
Authors: Hassan Y F , Merzah A N , Hassan S K Abdul , Tuaimah F M
Published: March 2021

Most developing countries are now working to combat imbalances between power generation and load demand. In such situations, load shedding schemes have been implemented frequently as rapid solutions for unbalanced conditions to protect networks from collapsing and to sustain stability. The conventional methods of load shedding disconnect loads without considering their priorities. In this work, a logarithmic reduction method is thus proposed to reduce loads according to the priority and criticality. A Reduction Matrix is introduced as a tuning factor scaled to the size of the network, and the paper thus presents an optimisation tool based on Genetic Algorithms, developed in MATLAB, that can be applied to minimise the error between the amount of load to be reduced and the actual load reduced in electric power systems. The proposed algorithm was tested on a practical data system sample as provided by the Iraqi Ministry of Electricity from the control center of the Iraqi national grid in Baghdad, and was shown to offer optimal load reduction with reduce error, which is necessary to eliminate the impact of load reduction in electrical networks on critical loads when total demand cannot be supplied. The simulation results thus support the effectiveness and practicality of the applied method, paving the way for its possible application in power systems.
Power Loss Reduction and Voltage Profile Improvement Using Optimal Placement of FACTS Devices
Authors: Daealhaq H M , kfajey Y F , Tukkee A S
Published: March 2021

The crucial role of an electric power system is to generate sufficient electricity to meet customer demands with an acceptable level of reliability in an economic manner. In recent years, Flexible AC Transmission Systems (FACTS) devices have been widely used to increase power system operation flexibility and controllability to meet this need. This paper presents an application of Differential Evolution (DE) to optimise the allocation of a Thyristor Controlled Series Capacitor (TCSC), a Static Var Compensator (SVC), and Unified Power Flow Controller (UPFC), as example FACTS devices. The objective of the research was to reduce power losses and improve the voltage profile in an IEEE 30-bus test system. The system performance was assessed with and without each FACTS device under different scenarios of load increase at up to 150% of the base case. The results obtained are encouraging in terms of reassessing electrical restructuring.
A Step-Up Controller Based on Fuzzy Logic Strategy to be Implemented in Photovoltaic Systems
Authors: Almawlawe M D H , Al-badri M , Alsakini I H
Published: March 2021

This paper applies an artificial intelligence or fuzzy logic strategy to improve the performance of photovoltaic systems with regard to variations of I-V and P-V characteristics resulting from irradiance and temperature variations that in turn create maximum power point (MPPT) variation, resulting in fluctuation of the DC voltage at the input of the boost step converter. A fuzzy logic controller is used to regulate this output voltage that can cover a wide operating range and does not require exact mathematical modelling, thus being cheap to develop. The performance of the DC converter based on the application of the fuzzy logic strategy was tested using MATLAB/Simulink for different values of input DC voltage within the PV system. The results show a good stabilising ability during irradiation changes and smooth signal output from the converter.
The Role of tungsten in trimetallic Co-Mo-W/γ-Al2O3 heterogeneous catalysts for efficient hydro-desulphurisation
Authors: Mahdi Fouad K , Albdiry Mushtaq T
Published: March 2021

This study investigates the effect on catalytic activity of inserting tungsten metal (W) into trimetallic W-Mo-Co supported on a Gamma-Alumina (γ-Al2O3) heterogeneous catalyst used for hydrodesulphurisation (HDS) in an oil refinery. Bimetallic Co5Mo15/γ-Al2O3 and a trimetallic Co5Mo14W1/γ-Al2O3 catalysts were synthesised using incipient wetness impregnation. The synthesised trimetallic Co5Mo14W1/γ-Al2O3 catalyst exhibited better catalytic performance, with an 88% hydro-removal percentage of sulphur based on an HDS reaction of petroleum naphtha as compared to the 82% for the bimetallic 5Co-15Mo/γ -Al2O3 catalyst under the same operational conditions at a pressure of 11.5 bar, a temperature 598 K, and a reaction time of 3 hr. This enhanced catalyst activity can be attributed to the presence of tungsten increasing the number of metal sites on the catalyst’s reaction surface.
Numerical Transfer Path Analysis for NVH System-Simulation Models
Authors: Pasch Gerwin , Jacobs Georg , Berroth Joerg
Published: March 2021

For the assessment of the Noise, Vibration and Harshness (NVH) behavior of complex systems in early phases of the development process, validated modelling methods are available that allow the prediction of structure-borne and airborne noise at system level. However, due to large model sizes, the identification of weak spots in the vibroacoustic transfer behavior and the derivation of optimization measures are highly complex, time-consuming, and mostly not practical. In the field of experimental NVH analysis, transfer path analysis (TPA) has been established as target-oriented methods for identifying vibroacoustic anomalies at system level. In this contribution, TPA methods from the field of measurement technology are selected and applied to numerical NVH system models, aiming for high accuracy and low computational effort in post-processing. The applications of the methods are shown and discussed using an elastic multi-body simulation model of a tractor drivetrain with a transient run-up of the vehicle speed as an example. The classical direct-force and component-based blocked-force TPA methods selected and adapted for this study allow for efficient calculation of the sound contributions of numerical models. At the same time, they overcome typical challenges of experimental TPA, such as exact force determination or consideration of rotational degrees of freedom. In addition, the comparison of the two methods shows that the path contributions are in general different for classical and component-based TPA and only under specific conditions the same. Both numerical TPA methods allow for the identification of weak spots in the NVH behavior in an efficient and target-oriented way.
Active vibration control of slewing drives with gear backlash
Authors: Spiegelhauer M , Schlecht B
Published: March 2021

Geared transmissions with high reduction ratios are widely utilized in drive technology. Common to these drives is the occurrence of considerable gear backlash. If operating scenarios with repeated reversals of the rotational direction or changing load directions occur, the backlash will be traversed. To overcome the gear play, rotation angles of several hundred degrees can be required at the motor. As a result, unwanted vibrations can occur and high dynamic loads may arise. It is shown that an active vibration control strategy based on full state feedback (LQG) allows to reduce both the dynamic overload and the time for reversing the drive. The model-based design approach relies on two angular measurements only. Multibody system simulations of an exemplary drivetrain are used to verify the possible improvements.