• Parasites, Hosts and Diseases
• /
• 제55권5호
• /
• pp.533-540
• /
• 2017

Schistosoma mansoni is highly endemic in Tanzania and affects all age groups at different degrees. However, its control approach does not include adult individuals who are equally at risk and infected. To justify the inclusion of adult individuals in MDA programs in Tanzania, the present study focused on determining the prevalence of S. mansoni infection and its related morbidities among adult individuals. This was a cross sectional study conducted among 412 adult individuals aged 18-89 years living in selected villages of Rorya and Butiama districts located along the shoreline of the Lake Victoria. A pretested questionnaire was used to collect socio-demographic and socio-economic information of participants. Ultrasonographic examinations were conducted for all study participants using the Niamey protocol. A single stool sample was obtained from all study participants and examined for S. mansoni using the Kato-Katz technique. The study revealed a high prevalence of S. mansoni (56.3%), and the majority of infected individuals had a light intensity of infection. Ultrasonographic findings revealed that 22.4% of adult individuals had periportal fibrosis (PPF) (grade C-F), with 18.4% having grade C and D and 4% having grade E and F. Males had the highest prevalence of PPF (31.7% vs 10.8%, P<0.001). Organomegaly was common with 28.5% and 29.6% having splenomegaly and hepatomegaly, respectively. S. mansoni infection and its related morbidities included PPF, hepatomegaly, and splenomegaly were common among adult individuals. To reduce the level of transmission of S. mansoni infection, planned mass drug administration campaigns should include adult individuals living in these villages.

• 원예과학기술지
• /
• 제31권1호
• /
• pp.14-23
• /
• 2013

This study evaluated the influence of light quality and intensity during healing and acclimatization on the $CO_2$ exchange rate, growth, and morphogenesis of grafted pepper (Capsicum annuum L.) transplants, using a system for the continuous measurement of the $CO_2$ exchange rate. C. annuum L. 'Nokkwang' and 'Tantan' were used as scions and rootstocks, respectively. Before grafting, the transplants were grown for four weeks in a growth chamber with artificial light, where the temperature was set at $25/18^{\circ}C$ (light/dark period) and the light period was 14 hours $d^{-1}$. The grafted pepper transplants were then healed and acclimatized under different light quality conditions using fluorescent lamps (control) and red, blue, and red + blue light-emitting diodes (LEDs). All the transplants were irradiated for 12 hours per day, for six days, at a photosynthetic photon flux (PPF) of 50, 100, or 180 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. The higher PPF levels increased the $CO_2$ exchange rate during the healing and acclimatization. A smaller increase in the $CO_2$ exchange rates was observed in the transplants under red LEDs. At a PPF of 180 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, the $CO_2$ exchange rate of the transplants irradiated with red LEDs was lowest and it was 37% lower than those irradiated with fluorescent lamps. The $CO_2$ exchange rates of transplants irradiated with blue LEDs was the highest and 20% higher than those irradiated under fluorescent lamps. The graft take was not affected by the light quality. The grafted pepper transplants irradiated with red LEDs had a lower SPAD value, leaf dry weight, and dry matter content. The transplants irradiated with blue LEDs had longer shoot length and heavier stem fresh weight than those irradiated with the other treatments. Leaves irradiated with the red LED had the smallest leaf area and showed leaf epinasty. In addition, the palisade and spongy cells of the pepper leaves were dysplastic and exhibited hyperplasia. Grafted pepper transplants treated with red + blue LEDs showed similar growth and morphology to those transplants irradiated with fluorescent lamps. These results suggest that high-quality grafted pepper transplants can be obtained by healing and acclimatization under a combination of blue and red lights at a high PPF level.

• Nuclear Engineering and Technology
• /
• 제46권4호
• /
• pp.513-520
• /
• 2014

In this paper, three types of operational and industrial absorbers used at research reactors, including Ag-In-Cd alloy, $B_4C$, and Hf are selected for sensitivity analyses. Their integral effects on the main neutronic core parameters important to safety issues are investigated. These parameters are core excess reactivity, shutdown margin, total reactivity worth of control rods, thermal neutron flux, power density distribution, and Power Peaking Factor (PPF). The IAEA 10 MW benchmark core is selected as the case study to verify calculations. A two-dimensional, three-group diffusion model is selected for core calculations. The well-known WIMS-D4 and CITATION reactor codes are used to carry out these calculations. It is found that the largest shutdown margin is gained using the $B_4C$; also the lowest PPF is gained using the Ag-In-Cd alloy. The maximum point power densities belong to the inside fuel regions surrounding the central flux trap (irradiation position), surrounded by control fuel elements, and the peripheral fuel elements beside the graphite reflectors. The greatest and least fluctuation of the point power densities are gained by using $B_4C$ and Ag-In-Cd alloy, respectively.

• 생물환경조절학회지
• /
• 제8권1호
• /
• pp.56-66
• /
• 1999

본 연구는 배양기의 환기횟수(0.1 $h^{-1}$ 또는 2.8 $h^{-1}$), 광도(70, 150 또는 220$\mu$mol. $m^{-2}$ . $s^{-1}$), C $O_{2}$ 농도(400-500, 1000 또는 2000$\mu$mol.mo $l^{-1}$)가 국화 소식물체의 기내생장에 미치는 영향을 조사하기 위하여 실시하였다. MS 배지에서 혼합영양배양 상태 하에서 번식시킨 줄기 마디 절편체를 채취하여 1.25meq. $L^{-1}$의 $H_{2}$S $O_{4}$$^{-}$가 추가로 첨가된 MS 기본배지가 담긴 3.7$\times$$10^{-4}$ $m^{3}$의 배양기에 용기당 4개씩 치상하였다. 환기횟수(NAEH)를 0.1 $h^{-1}$에서 2.8 $h^{-1}$로 향상시키기 위하여 배양용기의 뚜껑에 직경 10mm의 구멍을 뚫어 통기성의 필터를 부착하였으며, 당과 생장조절제는 첨가하지 않았다. 배양실에 C $O_{2}$를 공급하기 위하여 공기 순환통로에 C $O_{2}$ 가스 공급구를 설치하여 액화 C $O_{2}$ 가스를 명기 동안에만 공급해 주었다. 생체중과 건물중, 초장, 최대근장, 엽수, 엽면적은 광도(PPF)가 높은 처리구에서, 특히 C $O_{2}$ 농도가 높을 때 증가되었다. 그리고 환기횟수가 낮은 처리구에서보다 높은 처리구에서 더 컸으며, 처리효과는 배양후기로 갈수록 뚜렷이 증가되었다. 국화 소식물체의 기내생육은 환기횟수가 2.8 $h^{-1}$, PPF가 220$\mu$mol. $m^{-2}$ . $s^{-1}$, 그리고 C $O_{2}$ 농도가 2000$\mu$mol.mo $l^{-1}$일때 가장 빨랐다.

• 생물환경조절학회지
• /
• 제20권4호
• /
• pp.253-257
• /
• 2011

LED 보광이 파프리카의 착과와 생육에 미치는 영향을 구명하기 위해 파프리카 생육기간동안 일몰 후부터 5시간 동안 red(660nm), blue(460nm) red + blue(4 : 1)광을 작물의 50cm 상단에서 조사하였다. 광원별 광합성유효광량자속(PPF)은 red광 $79{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, blue광 $75{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, red + blue광 $102{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$였다. 파프리카 엽온은 LED 보광한 것이 무보광에 비하여 높았는데 blue광에서 가장 높았다. 한편 과실 온도는 무보광한 것이 가장 높았으며 엽온보다는 낮은 경향이었다. 파프리카 초장은 무보광에서 가장 길었고 blue LED에서 가장 짧았다. 잎 크기는 무보광에 비해 LED 보광한 것이 컸다. 과실무게는 LED 보광한 것이 무거웠으나 주당 과실 수와 상품과 수량은 무보광에 비해 적었다.

• 한국항공우주학회지
• /
• 제35권3호
• /
• pp.218-224
• /
• 2007

PZT와 같은 압전 재료는 능동 진동 억제 분야에서 널리 사용되고 있지만 단일 PZT의 경우 장착 과정에서의 손상, 전기 누전, 낮은 피로 성능과 같은 문제가 지적되고 있다. 이러한 문제를 해결하기 위하여 개발된 LIPCA 작동기는 여러 층의 복합재료와 PZT 층으로 구성되어 있다. 본 연구에서는 LIPCA 작동기를 끝단 질량이 부착된 알루미늄 외팔보의 진동을 억제하는데 적용하였다. 양변위 되먹임 제어 알고리듬을 사용하였으며, 필터 주파수를 대상 모드의 첫 번째 고유진동수에 맞추었다. 실험적으로 구한 알루미늄 보의 고유 진동수는 유한요소 해석의 결과와 잘 일치하였다. LIPCA 작동기를 능동 진동제어에 적용할 때 효율성을 시간과 주파수 영역에서 확인하고자 하였는데, 실험 결과 PPF제어를 사용한 LIPCA 작동기가 자유 진동의 안정화 시간과 강제 진동의 진폭을 효과적으로 제어할 수 있었다. 사례 연구로 다른 두께를 가지는 보의 강제 진동 제어를 수행하였다.

• 콘크리트학회지
• /
• 제6권4호
• /
• pp.123-130
• /
• 1994

폴리플로필렌 섬유를 첨가하여 콘크리트의 물성을 개선하려고 하는 많은 노력이 있어 왔으나, 아직 플라스틱계 섬유의 첨가에 따른 콘크리트의 거동에 대한 메카니즘은 명확히 밝혀지지 않은 상태이다. 플라스틱 섬유의 첨가에 따른 건조수축 균열의 조절 가능성을 분석하기 위하여 섬유의 첨가에 따른 유동성과 건조수축의 변화를 조사하였다. 섬유의 첨가에 따른 유동성의 변화와 건주수축을 측정하기 위한 실물 크기의 슬라브가 제작되었고, 섬유의 수분 흡착 특성 실험도 실기되었다. 실험 결과 섬유의 첨가는 상당한 유동성의 감소를 유발하기 때문에, 이를 보정하기 위한 추가적인 배합수가 필요했으며, 이에 따라 섬유의 첨가량에 비례하는 건조수축의 증가가 관측되었으나, 강도에는 큰 변화가 없는 것으로 관측되었다.

• 한국환경과학회지
• /
• 제30권11호
• /
• pp.907-914
• /
• 2021

In this study, strawberry cultivation environment in a greenhouse located in Jeonju was monitored and internal environmental parameters were analyzed. Temperature, humidity, RAD, and PPF sensors were installed to monitor environmental conditions in the test greenhouse. Data were collected every 10 minutes during four winter months from sensors placed across the greenhouse to assess its permeability and environmental uniformity. Temperature and humidity inside the greenhouse were relatively uniform with negligible deviations among the center, south, and north; however, it was judged that further analysis of gradients of these parameters from the east to the west of the greenhouse would be needed. Both RAD (Total solar radiation) and PPF (Photosynthetic photon flux) had high values on the south and were low on the north and the reduction rate of these parameters was 54% and 61%, respectively, indicating that a significant amount of light could not be transmitted. This implied a significant decrease in the amount of light entering the greenhouse during winter. Therefore, it is concluded that environmental control devices and auxiliary lighting are needed to achieve uniform greenhouse environment for efficient strawberry cultivation.

• Journal of Advanced Marine Engineering and Technology
• /
• 제32권3호
• /
• pp.437-445
• /
• 2008

This paper deals with the experimental assessment of the vibration suppression of the smart structures. First. we have presented a new high-speed active control system using the DSP320C6713 microprocessor. A peripheral system developed is composed of a data acquisition system, N/D and D/A converters, piezoelectric (PZT) actuator/sensors, and drivers for fast data processing. Next, we have tested the processing time of the peripheral devices, and provided the corresponding test results. Since fast data processing is very important in the active vibration control of the structures, we have focused on achieving the fast loop times of the control system. Finally, numerous experiments were carried out on the aluminum plate to validate the superior performance of the vibration control system at different control loop times.

• Journal of Power Electronics
• /
• 제14권3호
• /
• pp.444-457
• /
• 2014

This paper presents the design and realization of a digital PV simulator with a Push-Pull Forward (PPF) circuit based on the principle of modular hardware and configurable software. A PPF circuit is chosen as the main circuit to restrain the magnetic biasing of the core for a DC-DC converter and to reduce the spike of the turn-off voltage across every switch. Control and I/O interface based on a personal computer (PC) and multifunction data acquisition card, can conveniently achieve the data acquisition and configuration of the control algorithm and interface due to the abundant software resources of computers. In addition, the control program developed in Matlab/Simulink can conveniently construct and adjust both the models and parameters. It can also run in real-time under the external mode of Simulink by loading the modules of the Real-Time Windows Target. The mathematic models of the Push-Pull Forward circuit and the digital PV simulator are established in this paper by the state-space averaging method. The pole-zero cancellation technique is employed and then its controller parameters are systematically designed based on the performance analysis of the root loci of the closed current loop with $k_i$ and $R_L$ as variables. A fuzzy PI controller based on the Takagi-Sugeno fuzzy model is applied to regulate the controller parameters self-adaptively according to the change of $R_L$ and the operating point of the PV simulator to match the controller parameters with $R_L$. The stationary and dynamic performances of the PV simulator are tested by experiments, and the experimental results show that the PV simulator has the merits of a wide effective working range, high steady-state accuracy and good dynamic performances.