Search results for: flat feet

Authors: Ghada Mohamed Rashad, Doaa Ayoub Elimy, Mohamed Hussein Elgendy, Ahmed Mohamed Fathi Elshiwi, Mahmoud Ghazy

Abstract:

Background: Flat feet cause changes in foot mobility, foot posture, and load distribution under the foot which influences dynamic balance, that is essential in activities of daily living and for optimal performance in sports activity. Purpose: To investigate the effect of flat feet on dynamic balance including overall stability index (OAI), anteroposterior stability index (APSI) and mediolateral stability index (MLSI). Study Design: The design of the study was an experimental design. Subjects: Forty subjects from both sexes were selected from the Faculty of Physical Therapy, Cairo University, their mean age (23.55 ± 1.74 ) years, divided into two groups, group A (8 males and 12 females) with flat feet, and group B (9 males and 11 females) with normal feet. Methods: The Navicular Drop Test was used to determine if the feet were pronated and Biodex Balance System was used to assess dynamic balance at level 8 and level 4 for both groups. Results: There was no significant difference in dynamic balance including (OSI, APSI and MLSI) of the Biodex at stability level (8) (most stable) (p = 0.56). While there was a significant difference between both groups in all dependent variables at stability level (4) (less stable level) (p = 0.0001). Conclusion: It may be concluded that flat feet have an effect on dynamic balance and there is balance affection in subjects with flat feet.

Keywords: flat feet, dynamic balance, postural stability, types of flat feet, eversion strength

Procedia PDF Downloads 488

Authors: Michael Zaidman, Naum Simanovsky

Abstract:

Introduction. Symptomatic tarsal coalition with rigid flat foot often demands operative solution. An isolated coalition resection does not guarantee pain relief; correction of co-existing foot deformity may be required. The objective of the study was to analyze the results of combination of tarsal coalition resection and arthroereisis. Patients and methods. We retrospectively reviewed medical records and radiographs of children operatively treated in our institution for symptomatic calcaneonavicular or talocalcaneal coalition between the years 2019 and 2022. Eight patients (twelve feet), 4 boys and 4 girls with mean age 11.2 years, were included in the study. In six patients (10 feet) calcaneonavicular coalition was diagnosed, two patients (two feet) sustained talonavicular coalition. To quantify degrees of foot deformity, we used calcaneal pitch angle, lateral talar-first metatarsal (Meary's) angle, and talonavicular coverage angle. The clinical results were assessed using the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle Hindfoot Score. Results. The mean follow-up was 28 month. The preoperative mean talonavicular coverage angle was 17,75º as compared with postoperative mean angle of 5.4º. The calcaneal pitch angle improved from mean 6,8º to 16,4º. The mean preoperative Meary’s angle of -11.3º improved to mean 2.8º. The preoperative mean AOFAS score improved from 54.7 to 93.1 points post-operatively. In nine of twelve feet, overall clinical outcome judged by AOFAS scale was excellent (90-100 points), in three feet was good (80-90 points). Six patients (ten feet) obviously improved their subtalar range of motion. Conclusion. For symptomatic stiff or rigid flat feet associated with tarsal coalition, the combination of coalition resection and arthroereisis leads to normalization of radiographic parameters, clinical and functional improvement with good patient’s satisfaction and likely to be more effective than the isolated procedures.

Keywords: rigid flat foot, tarsal coalition resection, arthroereisis, outcome

Procedia PDF Downloads 26

Authors: Naum Simanovsky, Vladimir Goldman, Michael Zaidman

Abstract:

Background: The optimal algorithm for the management of symptomatic tarsal coalition is still under discussion in pediatric literature. It's debatable what surgical steps are essential to achieve the best outcome. Method: The investigators retrospectively reviewed the records of twelve patients with symptomatic tarsal coalition that were treated operatively between 2017 and 2019. Only painful flat feet were operated. Two patients were excluded from the study due to lack of sufficient follow-up. Ten of eleven feet were treated with the combination of calcaneal lengthening osteotomy (CLO) and resection of coalition (RC). Only one foot was operated with CLO alone. In half of our patients, Achilles lengthening was performed. For two children, medial plication was added. Short leg cast was applied to all children for 6-8 weeks, and soft shoe insoles for medial arch support were prescribed after. Demographic, clinical, and radiographic records were reviewed. The outcome was evaluated using American Orthopedic Foot and Ankle Society (AOFAS) Ankle Hindfoot Score. Results: There were seven boys and three girls. The mean age at the time of surgery was 13.9 (range 12 to 17) years, and the mean follow-up was 18 (range 8 to 34) months. The early complications included one superficial wound infection and dehiscence. Late complication includes two children with residual forefoot supination. None of our patients required additional operations during the follow-up period. All feet achieved complete deformity correction or dramatic improvement. In the last follow-up, seven feet were painless, and four children had some mild pain after intensive activities. All feet achieved excellent and good scoring on AOFAS. Conclusions: Many patients with talocalcaneal coalition also have rigid or stiff, painful, flat feet. For these patients, the resection of coalition with concomitant CLO can be safely recommended.

Keywords: Tarsal coalition, calcaneal lengthening osteotomy., flat foot, coalition resection

Procedia PDF Downloads 29

Authors: P. Hashim, M. S. Mohd Ridzwan, J. Bakar

Abstract:

Collagen was isolated from chicken feet by using papain and pepsin enzymes in acetic acid solution at 4°C for 24h with a yield of 18.16% and 22.94% by dry weight, respectively. Chemical composition and characteristics of chicken feet collagen such as amino acid composition, SDS-PAGE patterns, FTIR spectra and thermal properties were evaluated. The chicken feet collagen is rich in the amino acids glycine, glutamic acid, proline and hydroxyproline. Electrophoresis pattern demonstrated two distinct α-chains (α1 and α2) and β chain, indicating that type I collagen is a major component of chicken feet collagen. The thermal stability of collagen isolated by papain and pepsin revealed stable denaturation temperatures of 48.40 and 53.35°C, respectively. The FTIR spectra of both collagens were similar with amide regions in A, B, I, II, and III. The study demonstrated that chicken feet collagen using papain isolation method is possible as commercial alternative ingredient.

Keywords: chicken feet, collagen, papain, pepsin

Procedia PDF Downloads 379

Authors: Pakkinee Chitsakul

Abstract:

In this article, we would like to show that there is no cut point of any point in a plane, but there exists the cut locus of a point in a flat torus. By the results, we would like to determine the structure of cut locus of a flat torus.

Keywords: cut locus, flat torus, geodesics

Procedia PDF Downloads 299

Authors: Hamidreza Bayat, Arash Mirabdolah Lavasani, Meysam Bolhasani, Sajad Moosavi

Abstract:

Flow around a flat tube is studied numerically. Reynolds number is defined base on equivalent circular tube and it is varied in range of 100 to 300. Equations are solved by using finite volume method and results are presented in form of drag and lift coefficient. Results show that drag coefficient of flat tube is up to 66% lower than circular tube with equivalent diameter. In addition, by increasing l/D from 1 to 2, the drag coefficient of flat tube is decreased about 14-27%.

Keywords: laminar flow, flat-tube, drag coefficient, cross-flow, heat exchanger

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Authors: Maritza Granados Manjarrés

Abstract:

This paper makes part of an investigation project which experiments with flat surfaces in order to pleat them using tessellations and flat origami conditions. The aim of the investigation is to eventually propose not only a methodology on how to pleat those surfaces but also to find an structural system to make them work as building skins. This stage of the investigation emphasizes on the experimentation with flat surfaces and different kinds of folding patterns and shows the many examples that can be made from this experimentation.

Keywords: flat origami, fold, space, surface

Procedia PDF Downloads 264

Authors: Hema V. Vanar, R. K. Soni, N. D. Shah

Abstract:

Slabs supported directly on columns without beams are known as Flat slabs. Flat slabs are highly versatile elements widely used in construction, providing minimum depth, fast construction and allowing flexible column grids. The main objective of this thesis is comparison of analytical method and soft ware for analysis of flat slab subjected to various parametric loadings. Study presents analysis of flat slab is performed under different types of gravity.

Keywords: fat slab, parametric load, analysis, software

Procedia PDF Downloads 445

Authors: Hyoseong Lee, Duk-jin Kim, Jaehong Oh, Jungil Shin

Abstract:

Tidal flat in Korean peninsula is one of the largest biodiversity tidal flats in the world. Therefore, digital elevation models (DEM) is continuously demanded to monitor of the tidal flat. In this study, DEM of tidal flat, according to different times, was produced by means of the Drone and commercial software in order to measure seawater change during high tide at water-channel in tidal flat. To correct the produced DEMs of the tidal flat where is inaccessible to collect control points, the DEM matching method was applied by using the reference DEM instead of the survey. After the ortho-image was made from the corrected DEM, the land cover classified image was produced. The changes of seawater amount according to the times were analyzed by using the classified images and DEMs. As a result, it was confirmed that the amount of water rapidly increased as the time passed during high tide.

Keywords: tidal flat, drone, DEM, seawater change

Procedia PDF Downloads 171

Authors: Jamil Jafari, Sharafat Karimi

Abstract:

The Arabic Language has a complicated system of prosody invented by the great grammarian Khalil Ibn Ahmad Farahidi. He could extract 15 meters out of his innovative five circles, which were used in Arabic poetry of the 7th and 8th centuries. Then after a while, his student Akhfash added or compensated another meter to his tutor's meters, so overall, we now have 16 different meters in Arabic poetry. These meters have been formed by various combinations of 8 different feet and each foot is combined of rudimentary units called Sabab and Wated which are combinations of movement (/) and silent (ʘ) letters. On the other hand in English, we are dealing with another system of metrical prosody. In this language, feet are consisted of stressed and unstressed syllables and are of six types: iamb, trochee, dactyl, anapest, spondee, and pyrrhic. Using the descriptive-analytic method, in this research we aim at making a comparison between Arabic and English systems of metrical prosody to investigate their similarities and differences. The results show that both of them are quantitative and both of them rely on syllables in afoot. But unlike Arabic, English is utilizing another rhyme system and the number of feet in a line differs from Arabic; also, its feet are combined of stressed and unstressed syllables, while those of Arabic is a combination of movement and silent letters.

Keywords: Arabic prosody, English prosody, foot, meter, poetry

Procedia PDF Downloads 113

Authors: Hamidreza Bayat, Arash Mirabdolah Lavasani, Meysam Bolhasani, Sajad Moosavi

Abstract:

Heat transfer from flat tube is studied numerically. Reynolds number is defined base on equivalent circular tube which is varied in range of 100 to 300. In these range of Reynolds number flow is considered to be laminar, unsteady, and incompressible. Equations are solved by using finite volume method. Results show that increasing l/D from 1 to 2 has insignificant effect on heat transfer and Nusselt number of flat tube is slightly lower than circular tube. However, thermal-hydraulic performance of flat tube is up to 2.7 times greater than circular tube.

Keywords: laminar flow, flat tube, convective heat transfer, heat exchanger

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Authors: Hannah Kolano, Paul Nadan, Jeremy Ryan, Sophia Nielsen

Abstract:

The hooves of goats and other ruminants, or the family Ruminantia, are uniquely structured to adapt to rough terrain. Their hooves possess a hard outer shell and a soft interior that allow them to both conform to uneven surfaces and hook onto prominent features. In an effort to apply this unique mechanism to a robotics context, artificial feet for a hexapedal robot have been designed based on the hooves of ruminants to improve the robot’s ability to traverse unstructured environments such as those found on a rocky planet or asteroid, as well as in earth-based environments such as rubble, caves, and mountainous regions. The feet were manufactured using a combination of 3D printing and polyurethane casting techniques and attached to a commercially available hexapedal robot. The robot was programmed with a terrain-adaptive gait and proved capable of traversing a variety of uneven surfaces and inclines. This development of more adaptable robotic feet allows legged robots to operate in a wider range of environments and expands their possible applications.

Keywords: biomimicry, legged locomotion, robotic foot design, ruminant feet, unstructured terrain navigation

Procedia PDF Downloads 93

Authors: Sergey I. Chizhikov, Vladimir Y. Molchanov, Konstantin B. Yushkov

Abstract:

We demonstrate a method for adaptive spatial shaping of laser beams by means of acousto-optic Bragg diffraction. Transformation of the angular spectrum during Bragg diffraction is used to convert Gaussian intensity distribution into a flat-top one. Theoretical model is supported by the experiment.

Keywords: acousto-optics, flat top, beam shaping, Bragg diffraction

Procedia PDF Downloads 591

Authors: Mohamed Ali Alrabib

Abstract:

This paper introduces a paleoenvironmental and hydrocarbon show in this well was identified in the interval of Dembaba formation to the Hassaona formation was poor to very poor oil show. And from palaeoenvironmental analysis there is neither particularly good reservoir nor source rock have been developed in the area. Recent palaeoenvironment work undertakes that the sedimentary succession in this area comprises the Upper Paleozoic rock of the Carboniferous and Permian and the Mesozoic (Triassic) sedimentary sequences. No early Paleozoic rocks have been found in this area, these rocks were eroding during the Late Carboniferous and Early Permian time. During Latest Permian and earliest Triassic time evidence for major marine transgression has occurred. From depths 5930-5940 feet, to 10800-10810 feet, the TAI of the Al Guidr, the Bir Al Jaja Al Uotia, Hebilia and the top varies between 3+ to 4-(mature-dry gas). This interval corporate the rest part of the Dembaba Formation. From depth 10800- 10810 feet, until total sediment depth (11944 feet Log) which corporate the rest of the Dembaba and underlying equivalents of the Assedjefar and M rar Formations and the underlying Indeterminate unit (Hassouna Formation) the TAI varies between 4 and 5 (dry gas-black& deformed).

Keywords: paleoenveronments, thermail index, carboniferous, Libya

Procedia PDF Downloads 386

Authors: Reem I. Al-Ya' Goub, Nasim Shatarat

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This paper presents the results of analytical and comparative study among software programs' outputs in analysis of some two way solid slabs; flat plate, flat slab with beams and flat slab with drop panels problems that already been analyzed using Classical Equivalent Frame Method (CEFM) by several reinforced concrete book authors. The primary objective of this research is to determine the moment results using various software programs. Then, a summary of the results and differences percentages were obtained to show how analysis procedure effects the outputs of calculations that vary from software program to another when comparing them with the results of CEFM. Moment values were obtained using either the Equivalent Frame Method (EFM) or Finite Element Method (FEM) that's used among many software programs. The results of the analyses demonstrate that software programs vary markedly in terms of the information they provide to the structural designer regarding values of the model insertion, stiffness, effective moment of inertia used and specially the moment values.

Keywords: two-way solid slabs, flat plate, flat slab with beams, flat slab with drop panels, analysis, modeling, EFM, CEFM, FEM

Procedia PDF Downloads 385

Authors: Akhtar Malik Muhammad, Agha Mirwais

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Dams are considered to recharge aquifers by raising the water table, especially the ones near wells. The present study investigates the impact of dams on groundwater recharge in Jilga, Pakistan. The comparative analysis of changes in the groundwater table of the year 2012 and 2019 was carried out using ArcGIS 10.5 through the kriging method and remote sensing techniques to evaluate the mini dam's impact on the upstream area. Arc Info Spatial Analyze extension was used to find static water level maps of the years. The water table was observed minimum 67.08 feet and maximum 130.09 feet in 2012 whereas in 2019 the minimum water table level 49.89 feet and maximum 115.85 feet. Groundwater recharge with different ratio was noted, but the most significant was at Rabbani dam with 26ft due to supported lithology conditions and the lowest recharge was found at Garang dam14ft. The overall positive trend indicates the rehabilitation of dead karez and agriculture activities by increasing 36% the vegetation area in 2019. An over 6% increase in human settlement indicates socioeconomic development. Thus, it highlights the need for preferential focus on the construction of the dam so that the water level could be sustained to cater to the agricultural and domestic needs of the local population around the year

Keywords: water table, GIS, land cover, mini dams, agriculture

Procedia PDF Downloads 52

Authors: Nony Rahadiva

Abstract:

The development of housing in urban areas can not be separated from the high rate of population growth from both natural population growth and population growth due to migration. The development is bounded by urban land area so that construction of flats become a development priority. Quality of residential flats are influenced by the patterns of behavior of its inhabitants. The frequency of contact between the occupants become one of the effects of good social relations, but harmful activity can degrade the environment, especially in flats. One of the social relationships that can be seen on the flats development is the residents in Kutobedah flat built in Malang city. Problems that occur in that place is unfavorable flat management due to social activities such as daily activities and also the neighboring activities of apartment dwellers who tend not to pay attention to the environment. Based on these problems we can do a study on social interaction in Kutobedah flat and its influence on the management of flat facilities and infrastructures. This research was carried out by submitting a questionnaire to the residents of the apartment based social activities , operations and maintenance of the flats. By using a weighted analysis, we can find that social interaction tenants is high, but the level of infrastructure and facilities management of the tenants is low so it is needed to counsel the residents how to use and maintain the infrastructure properly.

Keywords: activities, flat, infrastructure management, social interaction

Procedia PDF Downloads 397

Authors: Fatema-Tuz-Zahura, Raquib Ahsan

Abstract:

Punching shear failure is usually the governing failure mode of flat plate structures. Punching failure is brittle in nature which induces more vulnerability to this type of structure. In the present study, a 3D finite element model of a flat plate with low reinforcement ratio and without any transverse reinforcement has been developed. Punching shear stress and the deflection data were obtained on the surface of the flat plate as well as through the thickness of the model from numerical simulations. The obtained data were compared with the experimental results. Variation of punching stress with respect to deflection as obtained from numerical results is found to be in good agreement with the experimental results; the range of variation of punching stress is within 5%. The numerical simulation shows an early and gradual onset of nonlinearity, whereas the same is late and abrupt as observed in the experimental results. The range of variation of punching stress for different slab thicknesses between experimental and numerical results is less than 15%. The developed numerical model is useful to complement available punching test series performed in the past. The results obtained from the numerical model will be helpful for designing retrofitting schemes of flat plates.

Keywords: flat plate, finite element model, punching shear, reinforcement ratio

Procedia PDF Downloads 218

Authors: Moustafa Elwan, Sohier Shehata, Fatma Sedek, Manar Hussine

Abstract:

One of the most risky factors that lead to a foot injury during physical activities are both high and low arched feet. Normally the medial longitudinal arch of the foot develops in the first 10 years of life, so flexible flat foot has an inversely relationship with age in the first decade, all over the world, the prevalence of flat foot is increasing. In approximately 15% of foot deformities cases, the deformity does not disappear and remains throughout adulthood, 90% of the clinical cases are complaining from foot problems are due to flatfoot. Flatfoot creates subtalar over pronation, which creates tibial and femoral medial rotation, and that is accompanied with increases of pelvic tilting anteriorly, which may influence the lumbar vertebrae alignment by increasing muscle tension and rotation. Objective: To study the impact of the flexible flatfoot on lumbosacral angle (angle of Ferguson). Methods: This experiment included 40 volunteers (14 females &26 males) gathered from the Faculty of Physical Therapy, Modern University of Technology and Information, Cairo, Egypt, for each participant, four angles were measured in the foot( talar first metatarsal angle, lateral talocalcaneal angle, , Calcaneal first metatarsal angle, calcaneal inclination angle) and one angle in the lumbar region (lumbosacral angle). Measurement of these angles was conducted by using Surgimap Spine software (version 2.2.9.6). Results: The results demonstrated that there was no significant correlation betweenFerguson angle and lateral talocalcaneal (r=0.164, p=0.313). Also, there was no significant correlation between Ferguson angle and talo first metatarsal “Meary’s angle" (r=0.007, p=0.968). Moreover, there was no significant correlation between Ferguson angle and calcaneal-first metatarsal angle (r=0.083, p=0.612). Also, there was no significant correlation between Ferguson angle and calcaneal inclination angle (r= 0.032, p= 0.846). Conclusion: It can be concluded that there is no significant correlation between the flexible flat foot and lumbosacral angle So, more study should be conducted in large sample and different ages and conditions of foot problems.

Keywords: calcaneal first metatarsal, calcaneal inclination, flatfoot, ferguson’s angle, lateral talocalcaneal angle, lumbosacral angle, and talar first metatarsal angle

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Authors: Mahsa Mahtab, Morteza Habibi

Abstract:

The effect of different anode tip geometries on the intensity of soft and hard x-ray emitted from a 4 kJ plasma focus device is investigated. For this purpose, 5 different anode tips are used. The shapes of the uppermost region of these anodes have been cylindrical-flat, cylindrical-hollow, spherical-convex, cone-flat and cone-hollow. Analyzed data have shown that cone-flat, spherical-convex and cone-hollow anodes significantly increase X-ray intensity respectively in comparison with cylindrical-flat anode; while the cylindrical-hollow tip decreases. Anode radius reduction at its end in conic or spherical anodes enhance SXR by increasing plasma density through collecting a greater mass of gas and more gradual transition phase to form a more stable dense plasma pinch. Also, HXR is enhanced by increasing the energy of electrons colliding with the anode surface through raise of induced electrical field. Finally, the cone-flat anode is introduced to use in cases in which the plasma focus device is used as an X-ray source due to its highest yield of X-ray emissions.

Keywords: plasma focus, anode tip, HXR, SXR, pinched plasma

Procedia PDF Downloads 368

Authors: Jay Prakash Singh

Abstract:

The aim of the present paper is to study properties of Quasi conformally flat LP-Sasakian manifolds with a coefficient α. In this paper, we prove that a Quasi conformally flat LP-Sasakian manifold M (n > 3) with a constant coefficient α is an η−Einstein and in a quasi conformally flat LP-Sasakian manifold M (n > 3) with a constant coefficient α if the scalar curvature tensor is constant then M is of constant curvature.

Keywords: LP-Sasakian manifolds, quasi-conformal curvature tensor, concircular vector field, torse forming vector field, Einstein manifold

Procedia PDF Downloads 760

Authors: Simone Medio

Abstract:

If we observe many modern cities from above, we are typically confronted with a sea of asphalt-clad flat rooftops. In contrast to the modernist expectation of a populated flat roof, flat rooftops in modern multi-story buildings are rarely used. On the contrary, they typify a desolate and abandoned landscape encouraging mechanical system allocation. Flat roof technology continues to be seen as a state-of-fact in most multi-storey building designs and its greening its prevalent environmental justification. This paper aims to seek a change in the approach to flat roofing. It makes a case for the opportunity at hand for architectonically resolute, sheltered, livable spaces that make a better use of the environment at rooftop level. The researcher is looking for the triggers that allow for that change to happen in the design process of case study buildings. The paper begins by exploring Han Slawick covered roof terrace in Amsterdam as a simple and essential example of transforming the flat roof in a usable, inhabitable space. It investigates the design challenges and the logistic, financial and legislative hurdles faced by the architect, and the outcomes in terms of building performance and occupant use and satisfaction. The researcher uses a grounded research methodology with direct interview process to the architect in charge of the building and the building user. Energy simulation tools and calculation of running costs are also used as further means of validating change.

Keywords: environmental design, flat rooftop persistence, roof re-habitation, tectonics

Procedia PDF Downloads 242

Authors: M. A. Alrabib, Y. Sherif, A. K. Mohamed, E. A. Elfandi, E. I. Fandi

Abstract:

This paper introduces a paleo-environmental and hydrocarbon show in this well was identified in the interval of Dembaba formation to the Hassaona Formation was poor to very poor oil show. And from palaeo-environmental analysis there is neither particularly good reservoir nor source rock have been developed in the area. Recent palaeo-environment work undertakes that the sedimentary succession in this area comprises the Upper Paleozoic rock of the Carboniferous and Permian and the Mesozoic (Triassic) sedimentary sequences. No early Paleozoic rocks have been found in this area, these rocks were eroding during the Late Carboniferous and Early Permian time. During Latest Permian and earliest Triassic time evidence for major marine transgression has occurred. From depths 5930-5940 feet, to 10800-10810 feet, the TAI of the Al Guidr, the Bir Al Jaja Al Uotia, Hebilia and the top varies between 3+ to 4-(mature-dry gas). This interval corporate the rest part of the Dembaba Formation. From depth 10800- 10810 feet, until total sediment depth (11944 feet Log) which corporate the rest of the Dembaba and underlying equivalents of the Assedjefar and M Rar Formations and the underlying Indeterminate unit (Hassouna Formation) the TAI varies between 4 and 5 (dry gas-black and deformed).

Keywords: paleoenvironmental, thermal alteration index, north western Libya, hydrocarbon

Procedia PDF Downloads 437

Authors: Rabab Allouzi, Amer Alkloub

Abstract:

As the complex shaped buildings become a popular trend for architects, this paper is presented to investigate the performance of reinforced concrete flat plate-inclined column connection. The studies on the inclined column and flat plate connections are not sufficient in comparison to those on the conventional structures. The effect of column angle of inclination on the punching shear strength is found significant and studied herein. This paper presents a non-linear finite element based modeling approach to estimate behavior of RC flat plate inclined column connection. Results from simulations of RC flat plate-straight column connection show good agreement with experimental response of specimens tested by other researchers. The model is further used to study the response of inclined columns to punching at various ranges of inclination angles. The inclination angle can be included in the punching shear strength provisions provided by ACI 318-14 to account for the effect of column inclination.

Keywords: punching shear, non-linear finite element, inclined columns, reinforced concrete connection

Procedia PDF Downloads 211

Authors: Wayne Tarrant, Ethan Petersen

Abstract:

The concept of a flat tax goes back to at least the Biblical tithe. A progressive income tax was first vociferously espoused in a small, but famous, pamphlet in 1848 (although England had an emergency progressive tax for war costs prior to this). Within a few years many countries had adopted the progressive structure. The flat tax was only reinstated in some small countries and British protectorates until Mart Laar was elected Prime Minister of Estonia in 1992. Since Estonia’s adoption of the flat tax in 1993, many other formerly Communist countries have likewise abandoned progressive income taxes. Economists had expectations of what would happen when a flat tax was enacted, but very little work has been done on actually measuring the effect. With a testbed of 21 countries in this region that currently have a flat tax, much comparison is possible. Several countries have retained progressive taxes, giving an opportunity for contrast. There are also the cases of Czech Republic and Slovakia, which have adopted and later abandoned the flat tax. Further, with over 20 years’ worth of economic history in some flat tax countries, we can begin to do some serious longitudinal study. In this paper we consider many economic variables to determine if there are statistically significant differences from before to after the adoption of a flat tax. We consider unemployment rates, tax receipts, GDP growth, Gini coefficients, and market data where the data are available. Comparisons are made through the use of event studies and time series methods. The results are mixed, but we draw statistically significant conclusions about some effects. We also look at the different implementations of the flat tax. In some countries there are equal income and corporate tax rates. In others the income tax has a lower rate, while in others the reverse is true. Each of these sends a clear message to individuals and corporations. The policy makers surely have a desired effect in mind. We group countries with similar policies, try to determine if the intended effect actually occurred, and then report the results. This is a work in progress, and we welcome the suggestion of variables to consider. Further, some of the data from before the fall of the Iron Curtain are suspect. Since there are new ruling regimes in these countries, the methods of computing different statistical measures has changed. Although we first look at the raw data as reported, we also attempt to account for these changes. We show which data seem to be fictional and suggest ways to infer the needed statistics from other data. These results are reported beside those on the reported data. Since there is debate about taxation structure, this paper can help inform policymakers of change the flat tax has caused in other countries. The work shows some strengths and weaknesses of a flat tax structure. Moreover, it provides beginnings of a scientific analysis of the flat tax in practice rather than having discussion based solely upon theory and conjecture.

Keywords: flat tax, financial markets, GDP, unemployment rate, Gini coefficient

Procedia PDF Downloads 310

Authors: Paul Henshall, Philip Eames, Roger Moss, Stan Shire, Farid Arya, Trevor Hyde

Abstract:

Encapsulating the absorber of a flat plate solar thermal collector in vacuum by an enclosure that can be evacuated can result in a significant increase in collector performance and achievable operating temperatures. This is a result of the thermal insulation effectiveness of the vacuum layer surrounding the absorber, as less heat is lost during collector operation. This work describes experimental thermal insulation characterization tests of prototype vacuum flat plate solar thermal collectors that demonstrate the improvement in absorber heat loss coefficients. Furthermore, this work describes the selection and sizing of a getter, suitable for maintaining the vacuum inside the enclosure for the lifetime of the collector, which can be activated at low temperatures.

Keywords: vacuum, thermal, flat-plate solar collector, insulation

Procedia PDF Downloads 357

Authors: Hachemi Nouria

Abstract:

The olive tree is a Mediterranean tree, which belongs to the family Oleaceae. The Olea genus contains various species and subspecies, and the only species bearing edible fruit is Olea europaea. The desired issue in this study is to provide the current status of plant cover and especially the training in Olea europaea currently existing in the major centers of the region of Tlemcen. While based on the flora and biometric aspect of this plant germplasm. In order to make an assessment of the phytomass, we made measurements of the four parameters of the aerial part of the taxon: height, diameter, and canopy density to ten feet of the olive tree per station. The floristic analysis shows a certain floristic difference between the different stations. The vegetal formations reflect the biotic and abiotic conditions including climate affecting the ecosystem. Biometric study on the feet of Olea in the six study sites, has led us to conclude that the four measured parameters provides insight on the development or degradation of Olea feet depending on the layout of the stations and the factors environmental. We find that the terrains are havens for these assets. Also the local microclimate (Oued Thalweg) promotes the healthy development of this species.

Keywords: olivier, ecology, biometrics, Tlemcen, Algeria

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Authors: A. Maouassi, A. Beghidja, S. Daoud, N. Zeraibi

Abstract:

This paper illustrates a practical application of nanoparticles (TiO₂) as working fluid to stimulate solar flat plate collector efficiency with heat transfer modification properties. A numerical study of nanofluids laminar forced convection, permanent and stationary, is conducted in a solar flat plate collector. The effectiveness of these nanofluids are compared to conventional working fluid (water), wherein the dynamic and thermal properties are evaluated for four volume concentrations of nanoparticles (1%, 3%, 5% and 10%), and this done for Reynolds number from 25 to 800. Results from the application of those nonfluids are obtained versus pressure drop coefficient and Nusselt number are discussed later in this paper. Finally, we concluded that the heat transfer increases with increasing both nanoparticles concentration and Reynolds number.

Keywords: CFD, forced convection, nanofluid, solar flat plate collector efficiency, TiO₂ nanoparticles

Procedia PDF Downloads 134

Authors: Azadeh Jafari, Farzin Ghanadi, Matthew J. Emes, Maziar Arjomandi, Benjamin S. Cazzolato

Abstract:

The turbulence within the atmospheric boundary layer induces highly unsteady aerodynamic loads on structures. These loads, if not accounted for in the design process, will lead to structural failure and are therefore important for the design of the structures. For an accurate prediction of wind loads, understanding the correlation between atmospheric turbulence and the aerodynamic loads is necessary. The aim of this study is to investigate the effect of turbulence within the atmospheric boundary layer on the surface pressure on a flat plate over a wide range of turbulence intensities and integral length scales. The flat plate is chosen as a fundamental geometry which represents structures such as solar panels and billboards. Experiments were conducted at the University of Adelaide large-scale wind tunnel. Two wind tunnel boundary layers with different intensities and length scales of turbulence were generated using two sets of spires with different dimensions and a fetch of roughness elements. Average longitudinal turbulence intensities of 13% and 26% were achieved in each boundary layer, and the longitudinal integral length scale within the three boundary layers was between 0.4 m and 1.22 m. The pressure distributions on a square flat plate at different elevation angles between 30° and 90° were measured within the two boundary layers with different turbulence intensities and integral length scales. It was found that the peak pressure coefficient on the flat plate increased with increasing turbulence intensity and integral length scale. For example, the peak pressure coefficient on a flat plate elevated at 90° increased from 1.2 to 3 with increasing turbulence intensity from 13% to 26%. Furthermore, both the mean and the peak pressure distribution on the flat plates varied with turbulence intensity and length scale. The results of this study can be used to provide a more accurate estimation of the unsteady wind loads on structures such as buildings and solar panels.

Keywords: atmospheric boundary layer, flat plate, pressure coefficient, turbulence

Procedia PDF Downloads 104

Authors: Ilze Pelece, Imants Ziemelis, Henriks Putans

Abstract:

Traditionally the solar energy has been used in southern countries, but it has been used also in northern ones. Most popular kind of use of solar energy in Latvia is solar collector for water heating. Traditionally flat-plate solar collectors are used because of simplicity of manufacturing. However, some peculiarities in use of solar energy in northern countries must be taken into account. In northern countries, there is lower irradiance, but longer day and longer path of the sun during summer. Therefore traditional flat-plate solar collectors are not appropriate enough in northern countries, but new forms must be developed. There are two forms of solar collectors - cylindrical and semi-spherical – proposed in this work. Such collectors can be made both for water or air heating. Theoretical calculations and measurements of energy gain from those two collectors have been done. Results show that daily energy sum received by the semi-spherical collector from the sun at the middle of summer is 1.43 times more than that of the flat one, but for the cylindrical collector, it is 1.74 times more than that of the flat one or equal to that of the tracking to sun flat-plate collector. The resulting difference in energy gain from collector will be not so large because of the difference in heat loses. Heat can be decreased by switching off the water circulation pump when the sun is covered by clouds. For this purpose solar batteries, powered pump can be used instead of complicated and expensive automatics. Even more important than overall energy gain is the fact that semi-spherical and cylindrical collectors work all day (17 hours in the middle of summer at 57 northern latitudes), while flat-plate collector only about 11 hours. Yearly energy sum received by the collector from the sun is 1.5 and 1.9 times larger for the semi-spherical and cylindrical collector respectively as for the flat one. The cylindrical solar collector is easier to manufacture, but semi-spherical one is more aesthetical and durable against the impact of the wind. Although solar collectors for water and air heating are studied in this article, main ideas are applicable also for solar batteries.

Keywords: cylindric, semi-spherical, solar collector, solar energy, water heating

Procedia PDF Downloads 233