1 |
CHEMCAD as a tool when teaching Chemical Engineering. / Chemcad software ModellingKhan, Imran Ullah January 2011 (has links)
The aim of this project was to design different chemical processes using Chemcad software. Following five Chemcad models that had industrial relevance were designed and discussed, production of nitric acid by ammonia oxidation process, Production of sodium carbonate by Solvay process, production of hydrogen by steam reforming of natural gas, production of sulphuric acid by Contact process and production of sulphur by Claus process. Equilibrium reactor, Gibbs reactor, absorption tower, heat exchangers, condensers, separators, pumps, compressors and mixers are designed on flow sheet diagram using Chemcad software. Mass balances and energy balances of Chemcad models were compared with bachelor thesis work and their differences and similarities were discussed in detail. In all processes reasonable results were obtained. Mostly in all cases results are the same as in the bachelor thesis. It was seen that equilibrium reactors give better results as compare to Gibbs reactors because when conversion factor of the chemical reaction was not known, Gibbs reactor was used and it adjust the conversion by itself according to equilibrium concentrations of the compounds. SI unit system was used in Chemcad models because in Sweden the SI system is very well established.
|
2 |
Effects of Shear Connector¿s Position in Profiled Sheeting on Strength and DuctilityLam, Dennis, Qureshi, J., Ye, J. January 2011 (has links)
No
|
3 |
Prediction of Longitudinal Shear Resistance of Composite Slabs with Profile Sheeting to EC4Lam, Dennis, Qureshi, J. January 2008 (has links)
No
|
4 |
Safety Evaluation of Diamond-grade vs. High-intensity Retroreflective Sheeting on Work Zone Drums: A Field Study and Driving Simulator Validation StudyBusam, Stephen G. 25 April 2011 (has links)
No description available.
|
5 |
Behaviour of Headed Shear Stud in a Push Test using Profiled Steel SheetingQureshi, J., Lam, Dennis, Ye, J. January 2009 (has links)
No
|
6 |
Finite element modelling of shear connection behaviour in a push test using profiled sheetingQureshi, J., Lam, Dennis, Ye, J. January 2010 (has links)
No
|
7 |
Investigation of a testing approach for trapezoidal crest fastened metal claddingStephan, Hendrik Christoffel 03 1900 (has links)
Thesis (MscEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Low-rise buildings with crest fastenedmetal cladding are susceptible to failures in the vicinity of the fasteners
during strongwind uplift conditions. These localised failures often lead to the progressive removal of cladding,
which can cause disastrous building damage. In South Africa, the current metal cladding design approach is
inadequate, since it solely relies upon manufacturer design specifications. These specifications are typically
designated as broad design guidelines for the maximum allowable cladding support spacings which are independent
from any specified design loads. This research focuses on the investigation of 0.50 mm ISQ550 IBR
cladding systems to understand basic cladding behaviour during static wind uplift conditions and to quantify
the uplift performance of IBR systems. The research investigation also included the improvement and
performance evaluation of a full-scale cladding test method which applies an air-bag loading method to simulate
static wind uplift conditions according to the revised SANS 10237:201X code of practice. This thesis may
serve as a basis for further cladding research, and the development of suitable standardised metal cladding
test methods in South Africa.
Several experimental investigation methods and limited finite element analyses (FEA) were used to investigate
IBR and the performance of the test methods. Tensile testing was used to determine the material properties of
the cladding metal. The full-scale cladding assembly testing was used to investigate the behaviour of IBR and
to evaluate the performance of the air-bag test rig. The localised behaviour of the cladding around the fasteners
was also investigated with a small cladding subassembly test method. The FEA served as a supplementary
investigation for IBR performance evaluation.
The experimental investigation confirmed that the static wind uplift resistances of IBR systems are mainly
governed by localised deformations of their fastened crests and fastener pull-through failures. The behaviour
and performance of IBR systems are heavily dependent on the crest fastening arrangement. IBR systems with
every crest fastening demonstrated a considerably higher wind uplift resistance than IBR systems with the
standard alternate crest fastening arrangement. The measured fastener loads were independent from span
length, whereas the overall uplift resistance of IBR reduced with increased span lengths. Load-span resistance
data for 0.50 mm ISQ550 IBR was derived from testing to provide a rational framework for design. The FEA
provided a reasonable simulation of IBR subjected to static wind uplift and confirmed the presence of high
stress and strain concentrations around the fastener holes which cause fastener pull-through failures. Therefore,
FEA can be used as an effective tool to investigate the behaviour of IBR. In conclusion, the air-bag test
method used in this research investigation provided an effective method for evaluating the uplift performance of crest fastened metal cladding. However, the air-bag load method is not capable of accurately simulating a
true uniformly distributed uplift load. It is recommended that direct air pressure testing be adopted for any
further research or commercial testing ofmetal cladding because direct air pressure testing is an effective and
proven test method for accurate simulation of static and cyclic wind uplift conditions. / AFRIKAANSE OPSOMMING: Metaalbekleding met kruinvashegting op lae geboue is geneig om te faal by die vashegters tydens toestande
van sterkwind-opheffing. As vashegters faal kan bekleding progressief verwyderwordomrampspoedige skade
aan die gebou te veroorsaak. Die huidige ontwerpmetode vir metaalbekleding in Suid-Afrika is onvoldoende,
aangesien dit slegs gegrond is op vervaardigers se ontwerpspesifikasies. Spesifikasies word gewoonlik verklaar
as breë ontwerpriglyne vir die maksimum toelaatbare spasiërings van ondersteunings sonder enige oorwegings
vir ontwerpbelastings. Hierdie navorsing fokus dus op 0.50mm ISQ550 IBR metaalbekleding omdie basiese
gedrag van bekleding tydens wind-opheffing beter te verstaan en die ophefweerstand van IBR te kwantifiseer
vir ontwerpdoeleindes. Verder ondersoek hierdie navorsing ook die verbetering en evaluasie van ’n
volskaalse bekledingstoetsmetode wat statiese wind-opheffing naboots met verspreide lugsakbelasting volgens
die hersiende SANS 10237:201X gebruikskode. Hierdie proefskrif kan dien as ’n grondslag vir verdere
navorsing en die ontwikkeling van geskikte standaard-toetsmetodes vir metaalbekleding in Suid-Afrika.
Verskeie eksperimentele toetsmetodes en beperkte eindige-element-analises (EEA) is gebruik om die gedrag
van IBR en die toets-opstellings te ondersoek. Trektoetse is gebruik om die meganiese eienskappe van die bekledingsmetaal
te bepaal. Volskaalse toets-opstellings is gebruik om die weerstand van IBR te ondersoek en
die lugsaktoetsmetode te evalueer. Die gelokaliseerde gedrag van die bekleding rondom die vashegters was
ook ondersoek met klein toets-opstellings. EEA het gedien as ’n aanvullende ondersoek om die gedrag van IBR te evalueer. Die eksperimentele ondersoek het bevestig dat die wind-ophefweerstande van IBR-stelsels hoofsaaklik bepaal
word deur gelokaliseerde deformasies van die vasgehegde kruine en die vashegters se deurtrekweerstand. Die
gedrag en weerstand van IBR-stelsels is ook grootliks afhanklik van die toegepaste vashegtingsmetode. IBR stelsels
met vashegting deur elke kruin het ’n hoër ophefweerstand verskaf as IBR-stelsels met die standaard
vashegtingsmetode deur elke tweede kruin. Die gemete vashegterbelastings was onafhanklik van die spanlengtes,
terwyl die algehele ophefweerstand van IBR verminder het vir langer spanlengtes. Toetsdata is gebruik
om ophefweerstande vir 0.50mm ISQ550 IBR oor verskeie spanlengtes af te lei sodat ’n rasionele raamwerk vir
ontwerp bewerkstellig kan word. Die EEA het die gedrag van IBR tydens toestande van statiese wind-opheffing
redelik goed nageboots en het ook die teenwoordigheid van hoë spannings- en vervormingskonsentrasies
rondom die vashegtergate, wat vashegters laat deurtrek, bevestig. Daarom kan EEA as ’n effektiewe instrument
gebruik word om die gedrag van IBR te ondersoek. Ten slotte word dit afgelei dat die lugsaktoetsmetode van
hierdie navorsingsondersoek ’n effektiewe metode verskaf het vir die gedrag-evaluering van kruinvasgehegte
bekleding tydens wind-opheffing. Die lugsaktoetsmetode kan egter nie ’n ware gelykverspreide ophefbelasting
naboots nie. Daarom word dit voorgestel dat toetsmetodes wat direkte lugdruk aanwend gebruik moet
word vir enige verdere navorsing of kommersiële toetse van metaalbekleding, aangesien dit ’n effektiewe en
bevestigde toetsmetode is wat statiese en sikliese opheftoestande akkuraat kan naboots.
|
8 |
Use of ultrasound to determine the effects of sheeting work input and barley β-glucan addition on mechanical properties of Asian wheat noodlesSalimi Khorshidi, Ali 05 June 2014 (has links)
Empirical tests developed for an objective evaluation of noodle texture as well as sensory methods provide no information about the rheological parameters responsible for differences in the texture of Asian noodles. Therefore, there is a need for a technique to evaluate the rheological properties of Asian noodles that is fast, easy and inexpensive. Promising results from ultrasonic assessments of the rheological properties of wheat flour doughs and preliminary noodle studies were an encouragement to use ultrasound to address such need in this thesis.
Using ultrasound at a relatively high frequency (1.4 MHz), the rheological properties of raw noodles made with three Canadian wheat varieties at various barley β-glucan (BBG) contents, sheeting work input levels and salt to kansui ratios (formulas) were evaluated. Conventional rheological, i.e., stress relaxation (SR) and uniaxial extension (Kieffer), measurements were employed for comparison purposes. The capability of ultrasound for evaluating the effects of BBG addition and sheeting work input on the rheological properties of raw wheat noodles of this study was confirmed. A greater sensitivity of ultrasound to microscopic changes in noodle dough structure, compared to SR and Kieffer tests, was reflected in differences between the results of ultrasound and those of the SR and Kieffer tests with respect to the influences of flour variety and formula on noodle rheology. Investigations of the density of raw noodles showed that air bubbles were present in the noodle dough matrix.
A simple, fast and low-cost method, based on the measurement of noodle dough dimensions during the sheeting process, was proposed for a quick evaluation of noodle dough rheology. The results of the proposed method were in agreement with those of conventional rheological measurements on the effects of flour variety and sheeting work input on noodle texture. The time-dependent effect of kansui on noodle dough structure was confirmed by comparing the results of this new method with those of SR and Kieffer tests with respect to the effect of formula on noodle rheology. Further investigations are proposed to establish this method for quick assessment of Asian wheat noodle rheology. / February 2017
|
9 |
Correlating dough elastic recovery during sheeting to flour analyses and rheological propertiesRen, Danqiu January 1900 (has links)
Master of Science / Department of Grain Science and Industry / Jon M. Faubion / Charles E. Walker / In commercial bakeries, the baker expects to get the same bread loaf, including weight
and size, after sheeting the same size dough piece. Doughs made from different flours have
different elastic recoveries to a great extent, which has an effect on the dough’s size and density.
Products made from differently elastic doughs can’t have the same shape and height. Weight
may also be affected.
The dough rheological behaviors of five flours and their blends having different chemical and physical properties were measured as were changes in thickness and snapback (thickness of the machined dough sheet relative to the roll gap) immediately following sheeting. Dough snapback was determined to be a function of both processing parameters, reduction ratio, and
dough rest time, as well as different flour properties. The predication equation for dough snapback is based on multiple flour properties and sheeting conditions.
Among the variables, Mixograph work, reduction ratio, and dough rest time were the
main factors affecting the elastic characteristics of the doughs. Minimum snapback occurred with the weakest flour experiencing the longest rest time and the smallest reduction ratio. A 7-factor equation was found to be robust to predict the snapback of several flours, by combining
Mixograph work, reduction ratio, dough rest time, Mixograph peak height and mixing time,
Alveograph P/L, and protein content.
|
10 |
Stabilisation of Steel Structures by Diaphragm Action of Trapezoidal SheetingNovotny, Ondrej January 2020 (has links)
The main idea behind stabilisation by diaphragm action is to create a deep beam thatcan resist horizontal loads acting on a structure. It is achieved by connecting the sheetingto the primary structure of the roof so that the edge beams resist the bending momentthrough normal stresses and the sheeting resists the shear force through shear stresses.An essential assumption of a functional diaphragm system is a sufficient connectionbetween the sheeting and the primary structure.In this thesis, the global behaviour of a diaphragm, as well as possible failure modesof sheeting of different thicknesses, are investigated.A laboratory experiment is conducted in the first part of the thesis. In the experiment,two types of self-drilling screws in combination with three different plate thicknesses aretested in shear. Slip flexibility of the screws is evaluated based on the experiment andcompared to flexibilities according to European Recommendations for the Application ofMetal Sheeting Acting as a Diaphragm.In the second part of the thesis, a finite element simulation is performed on two structuresto investigate the global behaviour of the diaphragm. The experimental results are,additionally, implemented into the finite element model.In the last part, hand calculations are performed based on analytical formulas given inEuropean Recommendations for the Application of Metal Sheeting Acting as a Diaphragmand the maximum horizontal displacement of the structure is compared to the FEAresults.
|
Page generated in 0.0712 seconds