Wood Physical and Mechanical Properties of Clonal Teak (Tectona grandis) Stands Under Different Thinning and Pruning Intensity Levels Planted in Java, Indonesia

( Gama Widya Seta ),( Fanny Hidayati ),( Widiyatno ),( Mohammad Na’iem ) 한국목재공학회 2023 목재공학 Vol.51 No.2

The objective of this study was to reveal the impact of thinning and pruning regimes on the physical and mechanical properties of clonal teak wood planted in Java. In this study, a 15-year-old clonal teak plantation was carried out and the obtained data were evaluated with analysis of variance (ANOVA). The results showed that different thinning intensities had a significant impact on the alteration of heartwood volume development (F = 25.63; p < 0.0001). Meanwhile, the impact of different thinning treatments in several physical properties depends on the pruning treatment levels [moisture content (F = 12.18, p < 0.0001); tangential shrinkage (F = 15.60, p < 0.0001); T/R ratio (F = 7.17, p < 0.0001); and volumetric shrinkage (F = 10.81, p < 0.0001)]. However, different thinning intensities had no significant impact on wood basic density alteration (F = 0.72, p = 0.486), while pruning intensities affect the differences between radial (F = 3.52, p = 0.030) and volumetric shrinkage (F = 3.13, p = 0.044). In mechanical properties, thinning intensity levels did not promote any significant differences [modulus of elasticity (F = 1.41, p = 0.248); modulus of rupture (F = 0.94, p = 0.392); compressive strength parallel to grain (F = 0.21, p = 0.813); and compressive strength perpendicular to the grain (F = 0.41, p = 0.669)]. Meanwhile, different pruning treatments and combination treatments were not significantly altered all mechanical properties. These results indicated that the thinning and pruning regimes can enhance the mechanical properties without having a serious alteration in the physical properties of clonal teak wood.

Dentinogenesis imperfecta type II: A case report with 17 years of follow-up

Gama, Francisco Jose Reis,Correa, Isabella Sousa,Valerio, Claudia Scigliano,Ferreira, Emanuelle de Fatima,Manzi, Flavio Ricardo Korean Academy of Oral and Maxillofacial Radiology 2017 Imaging Science in Dentistry Vol.47 No.2

Dentinogenesis imperfecta is a dominant autosomal hereditary disorder of dentin formation that affects the deciduous and permanent teeth. Its etiology is characterized by inadequate cell differentiation during odontogenesis. The clinical characteristics of dentinogenesis imperfecta are discolored teeth with a translucency that varies from gray to brown or amber. Radiographically, the teeth exhibit pulp obliteration, thin and short roots, bell-shaped crowns, and periapical bone rarefaction. The aim of this report was to present a case of dentinogenesis imperfecta type II that was followed up over a 17-year period. This report also presents scanning electron microscopy images of the enamel and dentin, showing that both were altered in the affected teeth. The disease characteristics and the treatments that were administered are reported in this study to guide dentists with respect to the need for early diagnosis and adequate follow-up to avoid major sequelae.

Impact of thinning and pruning on tree growth, stress wave velocity, and pilodyn penetration response of clonal teak (Tectona grandis) plantation

Gama Widya Seta,Widiyatno,Fanny Hidayati,Mohammad Naiem 한국산림과학회 2021 Forest Science And Technology Vol.17 No.2

The objective of this research was to examine the impact of different thinning and pruning intensities on the growth characteristics and wood properties of clonal teak. A 14-year-old clonal teak plantation was used in the study. The first thinning and pruning were established 5 years after planting. Three different levels of thinning (un-thinned, moderate, and heavy) and pruning (low, medium, high) were tested. Growth characteristics, pilodyn penetration, and stress wave velocity were examined. Results showed that different thinning intensities significantly affected the mean annual diameter increment (F = 37.67; p < 0.01). The standing stock estimations of the thinning intensity regimes also significantly differed between different thinning intensities (F = 4.16; p = 0.035). Moreover, pilodyn penetration significantly varied with the thinning treatment (F = 23.53; p < 0.01). The stress wave velocity, however, did not significantly vary with the thinning treatment (F = 2.54; p = 0.11). Meanwhile, the effect of pruning treatment was not observed under all parameters. Heavy thinning treatment promoted all parameters except height and stress wave velocity. A strong positive correlation was observed between pilodyn penetration and DBH. This result suggested that thinning and pruning promoted positive DBH growth and an increase in the economic value of the stand, but it did not affect the wood properties of clonal teak wood.

과수원의 관수 및 우박 보호를 위한 스마트 태양열 시스템에 관한 연구

가마타피크 ( Gama Tawfiq ),김용태 ( Yong-tae Kim ) 한국농공학회 2019 한국농공학회 학술대회초록집 Vol.2019 No.-

In the main apple producing countries of the European Union and America, the use of the anti-hail nets has been increasing, which is an only effective way to protect the fruit against the hail damage, even though there are negative effects like the interception of light, color and quality of fruits, sunburn, modifications of orchard climate, installation systems even the hail net is very costly (8000Eu/Ha). This remedy does not produce completely satisfactory results to the fruit crops. This study is divide in two parts: First part is to make a computer application which can simulate the Global Horizontal Irradiation in two countries Algeria and South Korea using the R-Sun model, This model computes for the global solar radiation based on time, location, surface and atmospheric conditions. Its inputs are an elevation raster and the day of the year. Location values are provided by latitude and longitude raster. In the second part, we design a management system of the orchard by using IoT technology. We used the ARDUINO mega2560 for the measurement of meteorological data (Temperature, Humidity, light intensity, Soil moisture) which are directly captured by the sensors (DHT11, VEML7700, soil moisture), all the data transmitted to the web server by using the shield ESP8266 Wi-Fi Module, the information appears instantly on a web page that enables us to control the irrigation pump (On/Off) and the opening/closing anti-hail system. From the results of Global Horizontal Irradiation (GHI) obtained in the region of Ghardaia in Algeria for a clear sky day, the daily measurements of GHI was 797W/m² at 10.00 am to 1029W/m² at midday and 537 w/m² at 17.00pm, comparing to the computed results by R-Sun ranged from 649W/m² at 10.00 am to 1009.61W/m² at midday and finally to 649.033 W/m² at 17.00 pm. The Mean Absolute Percentage Error between the measured and modeled GHI for all the day data is 5.61%, the model performs well for the Algerian measurements. This study can assist farmers to estimate the solar energy potential of farmland and for the orchard’s owners by using the IOT system they can be consulting all the meteorological data of the orchards from any place in any time by using phone connected to internet which can allow controlling irrigation and the anti-hail protection system. This feature allows to use the anti-hail net just in need which prevents negative effects on the fruits.

Boosting Power Generation by Sediment Microbial Fuel Cell in Oil-Contaminated Sediment Amended with Gasoline/Kerosene

Aleman-Gama, Elizabeth,Cornejo-Martell, Alan J.,Kamaraj, Sathish Kumar,Juarez, Katy,Silva-Martinez, Susana,Alvarez-Gallegos, Alberto The Korean Electrochemical Society 2022 Journal of electrochemical science and technology Vol.13 No.2

The high internal resistance (R_int) that develops across the sediment microbial fuel cells (SMFC) limits their power production (~4/10 mW m^-2) that can be recovered from an initial oil-contaminated sediment (OCS). In the anolyte, R_int is related to poor biodegradation activity, quality and quantity of contaminant content in the sediment and anode material. While on the catholyte, R_int depends on the properties of the catholyte, the oxygen reduction reaction (ORR), and the cathode material. In this work, the main factors limiting the power output of the SMFC have been minimized. The power output of the SMFC was increased (47 times from its initial value, ~4 mW m^-2) minimizing the SMFC R_int (28 times from its initial value, 5000 ohms), following the main modifications. Anolyte: the initial OCS was amended with several amounts of gasoline and kerosene. The best anaerobic microbial activity of indigenous populations was better adapted (without more culture media) to 3 g of kerosene. Catholyte: ORR was catalyzed in birnessite/carbon fabric (CF)-cathode at pH 2, 0.8M Na₂SO₄. At the class level, the main microbial groups (Gammaproteobacteria, Coriobacteriia, Actinobacteria, Alphaproteobacteria) with electroactive members were found at C-anode and were associated with the high-power densities obtained. Gasoline is more difficult to biodegrade than kerosene. However, in both cases, SMFC biodegradation activity and power output are increased when ORR is performed on birnessite/CF in 0.8 M Na₂SO₄ at pH 2. The work discussed here can focus on bioremediation (in heavy OCS) or energy production in future work.

Dentinogenesis imperfecta type II: A case report with 17 years of follow-up

Francisco José Reis Gama,Isabella Sousa Corrêa,Claudia Scigliano Valerio,Emanuelle de Fátima Ferreira,Flávio Ricardo Manzi 대한영상치의학회 2017 Imaging Science in Dentistry Vol.47 No.2

Dentinogenesis imperfecta is a dominant autosomal hereditary disorder of dentin formation that affects the deciduous and permanent teeth. Its etiology is characterized by inadequate cell differentiation during odontogenesis. The clinical characteristics of dentinogenesis imperfecta are discolored teeth with a translucency that varies from gray to brown or amber. Radiographically, the teeth exhibit pulp obliteration, thin and short roots, bell-shaped crowns, and periapical bone rarefaction. The aim of this report was to present a case of dentinogenesis imperfecta type II that was followed up over a 17-year period. This report also presents scanning electron microscopy images of the enamel and dentin, showing that both were altered in the affected teeth. The disease characteristics and the treatments that were administered are reported in this study to guide dentists with respect to the need for early diagnosis and adequate follow-up to avoid major sequelae.

압력에 따른 스프링클러 살수 분포 및 관개 효율 평가

가마자신토빈센트필립 ( Jacinto Vicente Filipe Gama ),홍성구 ( Seonggu Hong ) 한국농공학회 2020 한국농공학회 학술대회초록집 Vol.2020 No.-

Inadequate information about sprinklers especially in terms of coefficient uniformity and distribution uniformity is usually not given by the manufacturers, thus engineers are gettng into difficulty in correctly selecting appropriate sprinkler systems. The manufacturers provide the sprinkler specifications (throw or wetted radius of nozzle for different pressure, discharge volume, and precipitation for each nozzle). The main goal of this study is to evaluate water distribution uniformity, coefficient uniformity, and water application rates of a sprinkler system. The single sprinkler nozzl, HE-VAN of Rain bird^TM 15 series was evaluated through a set of experiments. The pressure is one of the most important factors that strongly affect irrigation uniformity and efficiency in a sprinkler irrigation system. The sprinklers were operated under different pressure and nozzle angle as recommended by the manufacture. The water depths were measured using catch cans which are located from the nozzle to the wetted radius for different pressures (1, 1.4, 1.7, and 2.1 bars) for 15 minutes. The results showed changes in both distribution coefficient and the coefficient of uniformity. The lowest coefficient uniformity (CU) and (DU) on nozzle 360°for the pressures 1.7 bar were 52% and 22%, respectively. The highest value of CU and DU were 70% and 34%, respectively at 1.4 bar. At the spray angles of 360°and 270°, higher water depth near to the nozzle and th depths decreased sharply along with the distance from the sprinkler. Meanwhile at the angles of 90°and 180°, higher water depths were located at 1.3 meters from the nozzle and then decreased at end of wetted radius. Wind influence affected distribution uniformity and coefficient uniformity. The results showed that irrigation engineers should take into serious consideration of the changes in the uniformity of water distribution by different pressures in designing and installation to achieve efficient irrigation.

Assessment of Irrigation Efficiency and Water Distribution by the Different Pressures and Nozzles angle of the Sprinkler Irrigation System

가마자신토빈센트필 ( Jacinto Vicente Filipe Gama ),홍성구 ( Seonggu Hong ) 한국농공학회 2020 한국농공학회 학술대회초록집 Vol.2020 No.-

Inadequate information about sprinklers especially in terms of coefficient uniformity and distribution uniformity is usually not given by the manufacturers, thus making an engineer difficult to correctly select a sprinkler. The manufacturers mention the sprinkler specifications (pressures for each nozzle with a radius of throwing wetted, discharge volume, and precipitation for each nozzle). The main goal of this study is to evaluate water distribution uniformity, coefficient uniformity, and water application rate surrounding a sprinkler on the single sprinkler. The single sprinkler Rain bird 15 series HE-VAN was evaluated under outdoor experimental conditions by measuring water depth. The pressure is one of the most important factors that strongly affect irrigation uniformity and efficiency in a sprinkler irrigation system. The sprinklers were operated under different pressure and nozzle angle as recommended by the manufacture. The Measurements of water depth using a catch can for sprinkler surroundings to the wetted radius have been done for different respective pressures (1bar, 1.4bar, 1.7 bar, and 2.1 bar) each within 15 minutes. The results show that the change in the distribution coefficient, the coefficient of uniformity change also. The lowest and highest coefficient uniformity (CU) and (DU) on nozzle 360°for the respecting pressure 1.7 bar & 1.4 bar is 22%, 52% of CU, and 70%,34% respectively. For the water application rate show that on 360° and 270° high water dept near to sprinkler and decreased sharply with the increasing distance from the sprinkler, while on 180° and 90°, high water dept increase in 1.3 meters from the sprinkler and then decrease at end of wetted area. Weather influence, causing low efficiency of distribution uniformity and coefficient uniformity. By this individual sprinkler evaluation, the irrigation system uniformity can be an input for an engineer to ensuring proper spacing is used in design and installation to meet the maximum irrigation efficiency.

Rate-based model for predicting and evaluating H2S absorption in the haloalkaliphilic biological desulfurization process

Zheng Chen,Gama Yang,Tingzhen Mu,Maohua Yang,Nadia A. Samak,Sumit Peh,Yunpu Jia,Xuemi Hao,Xuhao Zhao,Jianmin Xing 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.110 No.-

The highly efficient performance of H2S absorption is the crucial indicator for haloalkaliphilic biologicaldesulfurization (HBDS) because it immediately concerns the H2S removal efficiency and pH change ofalkaline solutions. Therefore, we investigated the effect of operating parameters on the H2S absorption’sperformance under haloalkaline conditions. The gas–liquid ratio and packing height significantly improveH2S removal efficiency, from 80% to 90% and 66% to 99%, respectively. The absorption temperature had atrivial impact on the H2S removal efficiency, and the maximum value appeared at 45 C. Additionally, alloperating parameters caused pH changes that varied in the acceptable range (0.1 to 0.5) during theabsorption process. A rate-based model was successfully developed to predict the haloalkaliphilic H2Sabsorption process accurately. Moreover, this model could be implemented to effectively evaluate theHBDS system’s stability and provide reliable theoretical guidance for the industrial HBDS process toensure good process stability.

Dust impact on concentrated solar power: A review

Kacem Zereg,Amor Gama,Mounir Aksas,Neelam Rathore,Fatiha Yettou,Narayan Lal Panwar 대한환경공학회 2022 Environmental Engineering Research Vol.27 No.6

Many sites with high solar radiation face high dust loads that reduce energy generation by concentrated solar power plants. This review presents the attenuative impacts of atmospheric aerosols, as well as reflectivity losses due to soiling of solar reflectors, by covering both experimental investigations and numerical studies; along with presenting the theoretical background. The chemical nature of aerosols, and the physics of soiling and atmospheric extinction phenomena (scattering and absorption) are also reviewed. Suspended particles like aerosols result in atmospheric extinction of the solar radiation that reaches the concentrators, and the deposition of these particles on the solar reflectors provokes decreases up to 80% in their reflectivity, and thus enhances the cumulus of optical losses and the reduction of energy production. Even though dust affects both CSP and photovoltaics, CSP technologies suffer more losses. The impact of dust should be particularly considered during the planning phase of solar thermal plants, since its consequent reduction in energy output can be severe. While there have been multiple papers to review dust-related problems for PV, the present paper is the first literature review dedicated to the impact of soiling on concentrated solar power.