Research on the design of non-traditional dynamic vibration absorber for damped structures under ground motion

N. D. Anh,N. X. Nguyen 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.2

An analytical approach is presented to investigate the optimal problem of non-traditional type of Dynamic vibration absorber (DVA) for damped primary structures subjected to ground motion. Different from the standard configuration, the non-traditional DVA contains a linear viscous damper connecting the absorber mass directly to the ground instead of the main mass. There have been many studies on the design of the non-traditional DVA for undamped primary structures. Those studies have shown that the non-traditional DVA produces better performance than the standard DVA does. When damping is present at the primary system, there are very few works on the non-traditional dynamic vibration absorber. To the best of our knowledge, there is no study on the design of non-traditional DVA for damped structures under ground motion. We propose a simple method to determine the approximate analytical solutions of the nontraditional DVA when the damped primary structure is subjected to ground motion. The main idea of the study is based on the criterion of the equivalent linearization method to replace approximately the original damped structure by an equivalent undamped one. Then the approximate analytical solution of the DVA’s parameters is given by using known results for the undamped structure obtained. Comparisons have been done to validate the effectiveness of the obtained results.

Effect of Impact Force on Tensile Properties and Fiber Splitting of Splittable Bicomponent Hydroentangled Fabrics

Ndaro, Mbwana Suleiman,Xiangyu, Jin,Ting, Chen,Yu, Chongwen The Korean Fiber Society 2007 Fibers and polymers Vol.8 No.4

The effect of impact force when using inclined water jets on splittable bicomponents hydroentangled fabrics are investigated focusing on changes in tensile properties and fiber splitting. The results indicated that with increase of impact force, the tensile strength was increased in both machine direction (MD) and crosswise direction (CD). On changing of water jet inclination angle, the tensile strength was the highest at 10 degree followed by 20 degree and the last 0 degree. The highest fiber splitting were observed in pie segment (PA6/PET) followed by island in sea (PA6/COPET) fiber but no fiber splitting was observed for island in sea (PET/COPET) fiber. The impact force in inclined mode of impact, played a great role in improving fiber splitting and tensile properties of hydroentangled nonwoven fabrics. The Scanning Electron Microscope (SEM) photos were used for investigation of fiber splitting by comparing fiber diameter before and after hydroentanglement.

In vitro and in silico studies of the antifungal properties of the bulb and leaves extracts of Drimia delagoensis Baker (Jessop)

Ndaba Nokuthula,Fotsing Marthe Carine,Anku William Wilson,Govender Penny Poomani 경희대학교 융합한의과학연구소 2020 Oriental Pharmacy and Experimental Medicine Vol.20 No.3

Drimia delagoensis (D. delagoensis), a member of the Hyacinthaceae family, is commonly used for the treatment of heartwater and skin ailments by the Zulus in South Africa. In this research study, the bulb and leaves of D. delagoensis were tested for their antifungal efficacy against Aspergillus fumigatus. Eight crude extracts were further analysed to determine the volatile chemical components of the plant using one-dimensional gas chromatography coupled with the time of fight mass spectrometry. The compounds detected from GC-MS were further subjected to molecular docking study to determine prospective relationship between the analysed compounds (1–9) and the active site of the glucosamine-6-phosphate synthase. All the crude extracts were effective against A. fumigatus. However, it was observed that dichloromethane: methanol (1:1) mixture for the bulb extracts had a high minimum fungal concentration values of (7.8 μg/mL) followed by hexane (7.8 μg/ mL) and ethyl acetate (7.8 μg/mL). Compounds (9Z,12Z)-9,12-Octadecadienoic acid(R)-2,3-bis[[(E)-2-methyl-2-butenoyl] oxy]propyl ester and 9-Octadecenoic acid (9Z)-,1-methyl-1,2-ethanediyl ester had higher binding affinities of − 47.69 and − 62.36 kcal/mol, respectively when compared to amphotericin B standard drug (− 44.19 kcal/mol). Furthermore, lipophilicity values for ligands, which ranged from − 11.46 to − 27.07, were more significant than those for amphotericin B (− 19.66), and this greater significance could also be ascribed to the potency of the crude extracts against A. fumigatus.

Effects of Different Light Wavelengths on the Growth of Olive Flounder (Paralichthys olivaceus)

Ndada Regina Benedict(엔다다 레지나 베네딕트),Yeo-Reum Kim(김여름),Jong-Myoung Kim(김종명) 한국생명과학회 2019 생명과학회지 Vol.29 No.3

빛의 파장이 넙치의 성장에 미치는 영향을 분석하기 위하여 보라색(400 nm), 청색(465 nm), 녹색(508 nm), 그리고 적색(635 nm)의 LED와 백색 형광등하에서 성장 실험을 수행하였다. 수조당 15마리 넙치를 12:12 시간 각 파장LED의 광주기하에서 60일 동안 사육한 결과, 각기 269.92±13.02%와 2.18±0.06(보라색), 363.21±3.74%와 2.56±0.07(청색), 433.22±4.83%와 2.79±0.01(녹색), 290.17±11.83%와 2.27±0.05(적색), 그리고 340.74±26.58%와2.47±0.10(형광등)의 체중 증가와 일간성장률(SGR: %/day)이 관찰되었다. 본 실험 결과 녹색 LED 하에서 넙치의 성장이 가장 빨랐으며, 적색 조명 하에서는 성장이 느린 것으로 나타났다. 대부분의 혈액 지표는 그룹별 차이가 없으나, 적색 LED조명 하에서 자란 넙치에서 높은 수준의 glutamic oxaloacetic transaminase (GOT)가 관찰되었다. 빛의 1차 감지 기관인 망막의 조직학적 분석 결과 광수용체 층의 상대적 두께에 별다른 영향이 없는 것으로 보아 녹색광이 무해함을 유추할 수 있다. To investigate the effects of light on growth in fish, olive flounder (Paralichthys olivaceus) were reared under four kinds of monochromatic light-emitting diodes (LEDs) at violet (400 nm), blue (465 nm), green (508 nm), and red (635 nm) wavelengths, along with a white fluorescent lamp as control. The rearing experiments were carried out with 15 fish per tank under different wavelength illumination at the same intensity. After rearing the fish under a 12 hr:12 hr light:dark photoperiod for 60 days, percentage increases in weight gain of 269.92±13.02, 363.21±3.74, 433.22±4.83, 290.17±11.83, and 340.74±26.58% and increases in specific growth rates (SGR) of 2.18±0.06, 2.56±0.07, 2.79±0.01, 2.27± 0.05, and 2.47±0.10 were observed in fish grown under the illumination of red, blue, green, and violet LEDs and the white fluorescent light, respectively. The results show faster growth in fish reared under green LEDs, but slower growth in those reared under red light. Differences in most blood parameters were minor, aside from an increased level of glutamic oxaloacetic transaminase in the fish grown under red LED illumination. Histological analysis of the retina showed few changes in the ratio of photoreceptor layer thickness to total retina thickness in fish reared under the green LEDs compared to those in other illumination groups. These results indicate that green LED light can foster increased growth in olive flounder with no distinct harmful effects on their light-sensitive photoreceptor layers.

Effect of Technology Incubation Programme on Entrepreneurship Development in Nigeria

NDAGI, Abdulmalik World Technopolis Association 2018 World Technopolis Review Vol.7 No.1

The lack of appropriate performance appraisal and evaluation of incubatees of technology incubation programmes in relation to entrepreneurship development in Nigeria is a major gap that needs to be bridged. This study examined the effect of selected technology incubation programme variables such as training, financing and marketing on entrepreneurship development in Nigeria. A closed-ended questionnaire was used for data collection from the quota-sampled population of the six (6) geo-political zones of Nigeria. Descriptive statistics were used to analyse the data while multiple regression was used to test the hypotheses. The results revealed that technology incubation training has a significant effect on entrepreneurial ability in Nigeria; there is a significant and positive effect of technology incubation financing on entrepreneurial funding portfolio; there is no significant impact of technology incubation marketing programme on entrepreneurial turnover; and technology incubation has no significant impact on entrepreneurial propensity. The study recommended that the National Board for Technology Incubation (NBTI) expand the training modules to capture pre, post and virtual incubatees; to facilitate access to risk funds, cheap capital and encourage establishment of venture capital; to improve on its marketing programme to encompass all marketing needs of incubatees beyond trade-fair participation. However, trade-fairs participation has a significant but limited effect on entrepreneurial turnover, while a technology incubation programme has no significant impact on entrepreneurial propensity, as only six (6) out of the twenty-nine (29) respondents started new venture from the incubation centers which are industrial training students and staff of the incubatees.

Effect of Technology Incubation Programme on Entrepreneurship Development in Nigeria

Abdulmalik NDAGI 세계과학도시연합 2018 World Technopolis Review Vol.7 No.1

The lack of appropriate performance appraisal and evaluation of incubatees of technology incubation programmes in relation to entrepreneurship development in Nigeria is a major gap that needs to be bridged. This study examined the effect of selected technology incubation programme variables such as training, financing and marketing on entrepreneurship development in Nigeria. A closed-ended questionnaire was used for data collection from the quota-sampled population of the six (6) geo-political zones of Nigeria. Descriptive statistics were used to analyse the data while multiple regression was used to test the hypotheses. The results revealed that technology incubation training has a significant effect on entrepreneurial ability in Nigeria; there is a significant and positive effect of technology incubation financing on entrepreneurial funding portfolio; there is no significant impact of technology incubation marketing programme on entrepreneurial turnover; and technology incubation has no significant impact on entrepreneurial propensity. The study recommended that the National Board for Technology Incubation (NBTI) expand the training modules to capture pre, post and virtual incubatees; to facilitate access to risk funds, cheap capital and encourage establishment of venture capital; to improve on its marketing programme to encompass all marketing needs of incubatees beyond trade-fair participation. However, trade-fairs participation has a significant but limited effect on entrepreneurial turnover, while a technology incubation programme has no significant impact on entrepreneurial propensity, as only six (6) out of the twenty-nine (29) respondents started new venture from the incubation centers which are industrial training students and staff of the incubatees.

Decentralization by Devolution in Tanzania: Bottom-up Participatory Approach to Local Government Planning

은다로 삼손 나무와일라(Ndaro Samson Nyamwaila),이양수(Yi Yangsoo) 영남대학교 박정희새마을연구원 2016 새마을학연구 Vol.1 No.2

본 연구는 탄자니아의 분권에 의한 분산(D에서 D로) 정책이 지방정부와 주민들의 상향식 개발 참여에 .미치는 영향력의 정도를 분석하는 것이다. 지방 분산의 기본 가정은 지방정부계획은 지역민의 요구와 가까이 있다는 것이며 주민이 직접 의사결정에 참여하거나 간접적으로 계획과정을 통해 영향력을 행사할 수 있어야 한다는 것이다. 본 연구에 사용된 자료는 제한된 시간과 재원으로 인해 2차 자료를 중심으로 연구가 이루어졌다. 2차 자료는 탄자니아와 관련된 다른 보고서에서 발표된 실증적 정보를 포함한다. 사례지역 연구결과를 보면 탄자니아의 분산과 분권에 의한 상향식 계획은 미미했으며 주민참여는 비효율적인 것으로 나타났다. 시민들은 그들이 무시당하고 의사결정 과정에서 제외되고 있다고 생각하기 때문에 자신의 삶의 발전과 연관된 결정에 영향을 미칠 수 있는 능력을 갖지 못하는 것 같다. 지방정부에 있어서 정책이 비효율적인 것은 정책기획이나 집행단계에 주민참여가 제대로 이루어지지 않기 때문이다. 본 연구는 사업의 지속성과 주인의식을 높이고 효과적이며 효율적인 사업이 되기 위해서는 지방 정부에 있어서 주민의 상향식 참여 계획이 되어야 한다고 제안한다. This paper examines how Decentralization and Devolution (D by D) in Tanzania is being related to bottom-up participatory planning in local governments. The basic assumption underlying the concept of decentralization is that Local Government Authorities (LGAs) are closer to local needs of the people at grassroots level, than people who should be directly involved in decision making or indirectly influence those decisions through planning process. The sources of information used are secondary data mainly because of limited time and financial resources, amongst other factors. The findings revealed that; D by D in Tanzania for the case of bottom-up participatory planning process is minimal and ineffective. Citizens do not seem to have the ability to influence decision over the matter affecting development of their lives because they believe that they were being ignored and sidelined in the decision making process. Adherence to planning process in LGAs was also noted as one of the reasons for ineffectiveness of the process as the citizens were not involved in the planning process rather they were involved in the implementation of set plans which sometimes did not include even their priorities. This paper suggests that bottom-up participatory planning in local government needs to be done properly as this will lead to increase in effectiveness and efficiency of the process including increased ownership of the projects and sustainability.

Effect of Garcinia kola seeds supplemented diet on growth performance and gonadal development of Oreochromis niloticus juveniles breed in ponds

Nyadjeu, Paulin,Angoun, Jeannette,Ndasi, Ngwasiri Pride,Tabi-Tomedi, Minette Eyango The Korean Society of Fisheries and Aquatic Scienc 2019 Fisheries and Aquatic Sciences Vol.22 No.9

Background: Despite the favorable geo-climatic potential of Cameroon, the national production of tilapia remains low due to poor tilapia growth reported by fish farmers. One of the underlying reasons is the early female maturation at a very small size and precocious breeding in earthen ponds, resulting in overpopulation which leads to stunted growth and therefore to the production of unmarketable fish size. Studies have shown that dietary supplementation of G. kola enhanced growth in young Clarias gariepinus and Oreochromis niloticus. It was also reported that G. kola inhibited spawning in Tilapia adult females. Therefore, this study sought to assess the effects of Garcinia kola as growth promoter and inhibitor of gonadal development in young Oreochromis niloticus. Methods: A total of 108 juveniles weighing $13.32{\pm}0.62g$ were randomly distributed in 9 hapas of 12 fishes each (9 females and 3 males) and fed for 70 days with three isonitrogenous diets, 40% crude protein with increasing Garcinia kola supplementation levels of 0 (normal diet), 6% and 10% (experimental diets). Physico-chemical parameters of the water (temperature, dissolved oxygen, pH, nitrate, nitrite, ammonia, and transparency) were measured twice a week. Every 14 days, fish were harvested, counted, and weighed. At the end of the experiment, three fish of each sex per replicate were sacrificed and their gonad and liver collected and weighed. Data were statistically analyzed using one-way analysis of variance repeated measure followed by Newman-Keuls multiple tests. Results: The results showed that all physico-chemical parameters of the water were within the recommended values for Tilapia culture. Tilapia fed 6% Garcinia kola supplemented diet displayed higher final body weight in males ($38.60{\pm}3.50g$) and females ($36.77{\pm}3.62g$) compared to those receiving normal diet ($36.23{\pm}1.36g$ and $25.87{\pm}3.32g$; respectively to the final body weight in males and females). The gonadosomatic index and hepatosomatic index indicated no significant variation in males while in females, these were significantly low in the experimental fish compared to control fish. Conclusion: The results of this study demonstrated that supplementation of G. kola seeds in diets of young Tilapia improved growth performance and impaired gonadal development in females.

Impact of Coping Strategies on Environmental Stressors of Athletes and Non-Athlete Undergraduate Students of University of Maiduguri, Nigeria

( Nahshon Likki ),( Mary Ndahi ),( Sheriff Jen ),( Stephen Hamafyelto ) 한국체육학회 2015 국제스포츠과학 학술대회 Vol.2015 No.1

Purpose: The objective of this study was to examine the impact of coping strategies on environmental stressors experienced by students of University of Maiduguri living off-campus. By rule, 100 and 400/500 level students are those entitled to hostel accommodation in the Federal Nigerian Universities with exceptions to private universities. In such circumstances most students preferred places with cheaper rent rates. Students in these residences face challenges of environmental stressors. Stress being a cumulative phenomenon, is known to build over time. These environmental stressors are inimical to students` ability to function well in their academic endeavors. Method: A descriptive survey was used to sample students living off-campus. Nine hundred and seven (N=907) students were sampled. Athletes, 294(32.4°)) and non-athletes, 613 (67.6%).The mean age was (24 ± 3.86). Male were 615(67.8%) and female were 292(32.2%). A 19 item checklist on environmental stressors .87 Cronbach`s alpha was used. A 10-item Orientation to Life Questionnaire .93 Cronbach`s alpha was used. Independent t-test was computed to compare the mean difference between athletes and non-athletes and the Multivariate analysis of Covariance (MANCOVA) was computed with age of students as covariate. Results: The results revealed that there was significant difference between athletes and nonathletes on the coping strategy (SOC) (t = 13.237, df; 905; p<0.05). However, no significant difference was observed between male and female students in terms of their coping strategies (t=2.860, df; 905; p>0.06).Statistical significant difference was observed between athletes and non- athletes on environmental stressors with athletes being more tolerant to the stressors (t = -1.141, df = 905; p<0.05). The MANCOVA showed significant difference between athletes and non- athletes as age of the students was held as covariate. Conclusion: It was concluded that University of Maiduguri undergraduate students who lived off-campus do experience environmental stressors in their residence while attending to academic activities. Apparently, the athletes who have their accommodation off-campus are better disposed to the environmental stressor than non-athletes. There was no gender difference in terms of environmental stressors or coping strategies. It is therefore recommended among other things that the university should evolve sports activities that would foster large number of students` participation.

Effect of Garcinia kola seeds supplemented diet on growth performance and gonadal development of Oreochromis niloticus juveniles breed in ponds

Paulin Nyadjeu,Jeannette Angoun,Ngwasiri Pride Ndasi,Minette Eyango Tabi-Tomedi 한국수산과학회 2019 Fisheries and Aquatic Sciences Vol.22 No.3

Background: Despite the favorable geo-climatic potential of Cameroon, the national production of tilapia remains low due to poor tilapia growth reported by fish farmers. One of the underlying reasons is the early female maturation at a very small size and precocious breeding in earthen ponds, resulting in overpopulation which leads to stunted growth and therefore to the production of unmarketable fish size. Studies have shown that dietary supplementation of G. kola enhanced growth in young Clarias gariepinus and Oreochromis niloticus. It was also reported that G. kola inhibited spawning in Tilapia adult females. Therefore, this study sought to assess the effects of Garcinia kola as growth promoter and inhibitor of gonadal development in young Oreochromis niloticus. Methods: A total of 108 juveniles weighing 13.32 ± 0.62 g were randomly distributed in 9 hapas of 12 fishes each (9 females and 3 males) and fed for 70 days with three isonitrogenous diets, 40% crude protein with increasing Garcinia kola supplementation levels of 0 (normal diet), 6% and 10% (experimental diets). Physico-chemical parameters of the water (temperature, dissolved oxygen, pH, nitrate, nitrite, ammonia, and transparency) were measured twice a week. Every 14 days, fish were harvested, counted, and weighed. At the end of the experiment, three fish of each sex per replicate were sacrificed and their gonad and liver collected and weighed. Data were statistically analyzed using oneway analysis of variance repeated measure followed by Newman-Keuls multiple tests. Results: The results showed that all physico-chemical parameters of the water were within the recommended values for Tilapia culture. Tilapia fed 6% Garcinia kola supplemented diet displayed higher final body weight in males (38.60 ± 3.50 g) and females (36.77 ± 3.62 g) compared to those receiving normal diet (36.23 ± 1.36 g and 25.87 ± 3.32 g; respectively to the final body weight in males and females). The gonadosomatic index and hepatosomatic index indicated no significant variation in males while in females, these were significantly low in the experimental fish compared to control fish. Conclusion: The results of this study demonstrated that supplementation of G. kola seeds in diets of young Tilapia improved growth performance and impaired gonadal development in females.