16 research outputs found
Feeding preferences and population parameters of sergestid shrimps, Acetes japonicus kishinouye in the coastal waters of Kedah, Malaysia
No full textFood and feeding habits, diet composition and population parameters of Acetes japonicus in the estuarine waters of Tanjung Dawai, Kedah Peninsular Malaysia were studied between June 2008 and May 2009. The total catches of Set Bag Net (SBN)were constituted of three major fauna groups and they were Acetes shrimps (89%), juvenile fishes (9%) and non- Acetes shrimps (2%). The annual mean percentage composition of sergestid shrimp comprising of A. japonicus, A. vulgaris and A. indicus were 89%, 7% and 4% espectively. Although seven species of juvenile fishes were recorded together in the bag net from the study area, the abundance was however very low (9%). Feeding habits of sergestid shrimps A. japonicus were done by examining the stomach contents of 164 specimens during one year study period. Analysis on the percentage of numerical abundance (Ci) showed that plant matter (28.18%) and crustacean appendages (18.70%) as the two highest values amongst the eight categories of feeding items. In addition, percentage frequency of occurrence (Fpi) values of phytoplankton, zooplankton, algae, plant matter, appendages of crustacean, debris, unidentified items and sand-mud were 3.45%, 7.05%, 5.07%, 27.44%, 17.42%, 15.80%, 8.94% and 19.81% espectively. From the diet composition found in the stomach, it is revealed that A. japonicus is probably omnivorous in feeding habit. Population parameters of male and female A. japonicus were studied using the monthly length frequency data by FiSAT software to evaluate the mortality rates and its exploitation level. The sex ratio (males: females) was found to be 1: 0.94. Asymptotic length (L∞) was 25.20 mm and 28.88 mm for male and female respectively. Growth co-efficient (K) for males and females was estimated at 1.80 yr-1 and 1.30 yr-1 respectively. Total mortality (Z) was calculated at 5.98 yr-1and 4.44 yr-1 for male and female of A. japonicus correspondingly. Natural mortality (M) was 2.82 yr-1 and 2.19 yr-1 for male and female shrimps. While fishing mortality (F) was 3.16 yr-1 and 2.25 yr-1 for male and female respectively. Exploitation level (E) for male and female of A. japonicus was calculated at 0.53 and 0.51. The exploitation level was slightly over (E > 0.50) the optimum level of exploitation (P = 0.50). The stock of A.japonicus was found to be slightly over exploited in Tanjung Dawai coastal waters
Diet composition and feeding habits of Acetes japonicus (Decapoda: Sergestidae) in estuarine waters of Tanjung Dawai, Kedah, Malaysia
No full textThis study describes the diet composition and feeding habits of sergestid shrimps Acetes japonicas. The stomach contents of 330 specimens, captured from the Estuary of Tanjung Dawai, Kedah from June 2008 - May 2009 were analysed. Analysis on the percentage of numerical abundance (Ci) showed that plant matter (28.18%) and crustacean appendages (18.70%) as the two highest values amongst the eight categories of feeding items. In addition, percentage frequency of occurrence (Fpi) values of phytoplankton, zooplankton, algae, plant matter, appendages of crustacean, debris, unidentified items and sand-mud were 3.54%, 7.05%, 5.07%, 27.44%, 17.42%, 15.80%, 8.94% and 19.81% respectively. Based on the food composition found in the stomach, it could be concluded that A. japonicus is a bottom feeder omnivorous
Biology and population dynamics of rainbow prawn, Parapenaeopsis sculptilis (Heller, 1862), in coastal waters of Terong, Perak, Malaysia
No full textTaxonomy, morphometry, food and feeding habits, reproduction and population
parameters of Parapenaeopsis sculptilis Heller 1862 in the coastal waters of Terong,
Perak, Peninsular Malaysia were studied between February 2012 and January 2013. A
total of 120 specimens of P. sculptilis were used for morphometric studies and they
were collected from four different locations viz. Perak, Penang, Port Dickson and
Malacca. The morphometric characteristics investigated include the total length,
standard length, carapace length, carapace height, rostral length, second pleon segment
height, sixth pleon segment length, telson length, telson width, eye wide and eye
length. The morphometric study is aimed to investigate on the possibility of differences
in body morphometric characteristics amongst the different P. sculptilis populations in
Peninsular Malaysia waters.The result showed that all morphometric characters of
P. sculptilis from four different areas in the west coast of Peninsular Malaysia were
significantly (P
0.50) not significant at 5% level. Feeding process particularly feeding items is one of
the important biological characteristics for species that has aquaculture potential. The
observation of the stomach contents of 360 specimens from coastal waters of Terong
Perak, found only 10.14% of empty stomachs of the P. sculptilis while 89.84% of the
stomachs filled up with foods. The highest percentages of full stomachs, 3/4 full, 1/2
full and 1/4 full were found in January, June, May and March respectively. The diet
compositions of P. sculptilis were grouped into nine different categories viz.
phytoplankton, zooplankton, mollusca, fish scales, polychaetes, appendages of
crustacean, detritus, sand and unidentified items. According to the Index of Relative
Importance (%IRI), the main food items of P. sculptilis graded as first rank was
molluscs (64.73%), and this was followed by appendages of crustacean (17.88%),
zooplankton (7.49%), detritus (2.64%), sand (2.27 %), phytoplankton (2.20%), fish
scales (1.84 %), unidentified items (1.19 %) and polychaetes (0.69%). The various composition of food items proved that the P. sculptilis is an omnivorous bottom feeder.
A study was also included to examine the sex ratio in the population of Terong coastal
waters and the annual results for the ratio was found to be 1:3.4 (Males: Females).
Consecutively, a study on the reproductive biology was carried out on 50 female
individuals each month. Samples were examined monthly and the peak Gonadosomatic
Index (GSI) of female P. sculptilis was very apparent during the months of April,
August and October in the study area. The first sexual maturity of female was attained
at a total length of 9.30 cm. The highest GSI value (5.89) was observed in April, where
the females were a mature stage. The lowest GSI (0.63) was obtained in November,
where the females were at an early active and immature phase. Relative condition
factor (Kn) values ranged from 0.99 to 1.064 (1.013±0.005, mean ±SD). Kn values
changes in various months: the highest peak was in March-April indicating the
spawning period and small peaks indicated the cycle of gonadal development. A total
of 3110 specimens of prawn were used for the works on the population dynamics of P.
sculptilis. The estimated mean total lengths for males and females were 9.13(±0.83)
and 11.96 (±2.2) cm. Length-weight relationship (LWR) parameters of both sexes was
estimated at W = 0.00027TL2.80. The estimated relative growth coefficient (b) was 2.80
for the both sexes which indicated that growth pattern of P. sculptilis was negative
allometric in the investigated area. Monthly length–frequency data were analysed by
using FiSAT (FAO ICLARM Stock Assessment Tools) software. The von Bertalanffy
growth (VBGF) parameters were estimated as asymptotic length (L) = 17.69 cm and
growth coefficirent (K) = 2 yr-1. The total mortality (Z), natural mortality (M) and
fishing mortality (F) were found to be 6.71, 1.77 and 4.94 yr-1 respectively. The
exploitation (E) rate was calculated as E = 0.74 which is higher than optimum level of
exploitation (E= 0.50). It is revealed that the status of the stock of P. sculptilis is over
exploited the in the coastal waters of Terong, Perak, Peninsular Malaysia
Efficienty of CFRP sheets in upgrading and/or strengthening square reinforced concrete columns
No full textStrengthening and/or upgrading reinforced concrete columns through utilization of composite sheets is now receiving wide acceptance worldwide. The technique is simple to use and has many advantages over other available methods. However, limited data is available about its efficiency in confining non-cylindrical shape columns. In this paper, the influence of using different schemes of wrapping of carbon fibre reinforced polymer (CFRP) sheets on the behaviour of reinforced concrete columns with and without utilizing
mechanical anchoring system is reported. The columns were 300 × 300 mm in cross section and 2005 mm in height and were subjected to incremental monotonic loading until complete failure. Test results indicated that the horizontally aligned CFRP sheets had more contribution to enhancing the ductility of the columns than the strength whereas the vertically aligned sheets had more contribution to increasing the column's ultimate capacity. The results also showed that both ductility and strength of the wrapped columns can be significantly increased by utilizing mechanical anchoring system that reduces the
distance between the unsupported nodal points for the sheets.Corresponding Author:
Prof. Saleh H. Alsayed, Civil Engineering Department, Department of Civil Engineering, King Saud University, P.O. Box 800, Riyadh 11421, Saudi Arabia. Email: [email protected]
Performance of glass fiber reinforced plastic bars as a reinforcing material for concrete structures
No full textThe increasing use of fiber reinforced plastic (FRP) bars to reinforce concrete structures necessitates the need for either developing a new design code or adopt the current one to account for the engineering characteristics of FRP materials. This paper suggests some modifications to the currently used ACI model for computing flexural strength, service load deflection, and the minimum reinforcement needed to avoid rupturing of the tensile reinforcement. Two series of tests were conducted to check the validity of the suggested modifications. The first series was used to check the validity of the modifications made into the flexural and service load deflection models. The test results of the first series were also analyzed to develop two simple models for computing the service load deflection for beams reinforced with glass FRP (GFRP) bars. The second series was used to check the accuracy of the modification suggested into minimum reinforcement model. Test results of the first series indicate that the flexural capacity of the beams reinforced by GFRP bars can be accurately predicted using the ultimate design theory. They also show that the current ACI model for computing the service load deflection underestimates the actual deflection of these beams. The two suggested models for predicting service load deflection accurately estimated the measured deflection under service load, and the simpler of the two pertains better predictions than those of the models available in the literature. Test results of the second series reveal that there is an excellent agreement between the predicted and recorded behavior of the test specimens, which suggests the validity of the proposed model for calculating the required minimum reinforcement for beams reinforced by GFRP bars.King Abdulaziz City for Science and Technology
(KACST), funded the research project AR-14-35 entitled "Glass Fiber Reinforced
Plastic Rebars: Properties and Applications in Concrete Structures."Corresponding Author:
Prof. Saleh Hamed Alsayed
Civil Engineering Deparatment, College of Engineering, King Saud University, P.O. Box 800
Riyadh-11421, Saudi Arabia.
Email: [email protected]
Non-linear finite element analysis for RC elements subjected to in-plane loads
No full textCivil Engineering Department, College of Engineering, King Saud University.
Riyadh, 11421, Saudi ArabiaA non-linear iterative solution of finite element formulation implemented a 486 personal computer for predicting the cracking shapes and their propagation in reinforced concrete elements subjected to in-plane stresses is presented. The model is based on a smeared crack representation and a plane stress state simulation. It considers the influence of concrete tension stiffening after cracking, compressive stress degradation due to cracking, and single and double crack conditions. The reliability of the model is checked against the experimental results for specimens that were tested by the author as well as those tested by other researchers. Comparisons of the results show that the proposed model predicts the measured results with an overall average error of 2% and a coefficient of variation of 1.48. This work forms an effective tool for investigation of inelastic behavior of a concrete and reinforcing bar composite
In Influencers We Trust- A Model of Trust Transfer in Social Media Influencer Marketing
No full textThis study is designed to investigate whether customers’ trust in social media influencers translates to them trusting the brands endorsed by said influencers. It, additionally, explores the role of brand liking and ad enjoyment in this model of trust transfer. Data was collected from 354 respondents who were asked to complete online survey questions after watching video adverts featuring social media influencers endorsing different brands. The dataset was then analyzed us-ing PLS-SEM techniques. Based on the analysis, influencer trust was found to positively affect brand trust, brand liking, and ad enjoyment. Brand liking was also found to positively affect customers’ brand trust. However, there was no support of ad enjoyment’s effect on customers’ brand trust. The results lend sup-port to the theory of trust transfer in the context of social media influencer mar-keting. The findings from this study are useful for social media influencers, as they highlight the importance of nurturing a trusting relationship between them and their audience. This trust is expected to transfer to customers’ trusting in and liking of endorsed brands and therefore contribute to the success of the social media influencer business model. This study adds insights to the still growing research on social media influencer marketing, specifically shedding light on the effects of customers’ trust in influencers, a much-discussed area of late.</p
Methodology for Selection of Sustainable Public Transit Routes: Case Study of Amman City, Jordan
No full textA limited number of previous studies have focused on the selection of transportation routes considering sustainable development goals (SDGs). In this research, a methodology for selecting sustainable public transit (PT) routes is presented, consisting of generating a feasible initial route set, optimization, and assessment. Total welfare, road safety, and reduction in total emissions are indicators of the economic, social, and environmental dimensions, respectively. Based on the transportation model, the network structure, attributes, and emission rates are exported. The travel demand of PT is modified by modal share. Additionally, the safety performance function (SPF) is developed as a safety measure. Regarding optimization, the optimum routes are obtained by maximizing PT share and minimizing PT travel time. Then, the new routes are implemented, and the network is evaluated and compared with the existing scenario in light of sustainability indicators. The case study is Amman BRT. The results show that the new network is more sustainable than the existing BRT network and achieves better performance than the selected scenario of Amman city. The new network can reduce travel time by more than 13%, decrease total emissions by more than 17%, and alleviate the crash frequency by more than 14%
Population dynamics of sergestid shrimps Acetes japonicus in the estuary of Tanjung Dawai, Kedah, Malaysia
No full textPopulation parameters of male and female A. japonicus were studied using the monthly length frequency data to evaluate the mortality rates and its exploitation level. The sex ratio (male: Female) was found at 1: 0.94. Asymptotic length (L∞) was 25.20 mm and 28.88 mm for male and female, respectively. Growth co-efficient (K) for males and females was estimated at 1.80 and 1.30 year-1, respectively. Total mortality (Z) was calculated at 5.98 and 4.44 year-1 for male and female of A. japonicus respectively. Natural mortality (M) was 2.82 and 2.19 year-1 for the male and female shrimps. The fishing mortality (F) was 3.16 year-1 for male and 2.25 year-1 for female. Exploitation level (E) for male and female of A. japonicus was calculated at 0.53 and 0.51. The exploitation level was slightly over (E>0.50) the optimum level of exploitation (p = 0.50). The stock of A. japonicus was found to be slightly over exploited in Tanjung Dawai estuarine waters
