Modifikasi Sirip (Fin) Spiral Pada Inner Pipe Dari Double Pipe Ground Heat Exchanger Untuk Meningkatkan Kapasitas Perpindahan Panas Dan Menurunkan Pressure Drop

In countries with subtropical climates, they need warmers in winter, therefore technology is needed to meet this. One of them is Ground Heat Exchanger, this tool is a heat exchanger by utilizing heat from the ground as a heating medium. This tool uses a coxial-double pipe system which consists of two pipes. More efficient performance improvements are needed. The study was conducted to increase the rate of heat transfer by adding a spiral fin without any increase in pressure drop. ANSYS Fluent software is used to simulate. Three spiral fin models were made with a pitch measuring 0.15 m perforated with variations in holes including n = 2, n = 3, and cross. Of the three variations of the model n = 2, it has a heat transfer value of 76.6034 W and a pressure drop value of 152.82 Pa. Model n = 3, has a heat transfer value of 71.3118 W and a pressure drop value of 150.31 Pa. The cross model has a heat transfer value of 105,834 W and a pressure drop value of 182,923 Pa. From the result, the ideal design model is n=2

Di-tert-Butyl 2,2′-[2,2′-methyl­enebis(naphthalene-2,1-diyldi­oxy)]diacetate

In the title compound, C33H36O6, two naphthalene ring systems are connected through a methyl­ene linkage [C—C—C = 114.9 (2)°]; the ring systems are aligned at an angle of 76.5 (1)°. Of the two –O–CH2–C(=O)–C(CH3)3 substituents, one adopts an extended conformation whereas the other is U-shaped. In the crystal, mol­ecules are linked via weak C—H⋯O hydrogen bonding, forming supra­molecular chains running along the c axis

tert-Butyl 2-(4-nitro­phen­oxy)acetate

In the title mol­ecule, C12H15NO5, the nitro­phen­oxy portion is approximately planar (r.m.s. deviation = 0.034 Å) and makes an angle of 84.8 (1)° with respect to the –CH2–C(=O)–O–C fragment. In the crystal, π–π stacking is observed between nearly parallel benzene rings of adjacent mol­ecules, the centroid–centroid distance being 3.6806 (10) Å. Weak inter­molecular C—H⋯O hydrogen bonding is present in the crystal structure

Bis[5-chloro-2-(prop-2-yn-1-yl­oxy)phen­yl]methane

The mol­ecule of the title compound, C19H14Cl2O2, has two benzene rings connected to a methyl­ene C atom, and the rings are aligned at 66.3 (1)°. Inter­molecular C—H⋯π and π–π stacking inter­actions are observed in the crystal structure, the centroid–centroid distances between parallel benzene rings being 3.7529 (12) and 3.6201 (12) Å, respectively

Factor affecting work-life balance among employees in Johor Bahru / Nurul Anis Faizah Mohamad Shah

The purpose of this study is to determine the relationship between workload, organizational support and role conflict towards employees in Johor Bahru work-life balance. The study involves the problem on what factor that affecting work-life balance and whether the three independent variables is significant. The targeted population is local employees who are currently working in Johor Bahru and the sample in this study covered 310 respondents from the total population. The sample was selected through convenience sampling. From 310 questionnaire distributed, only 292 questionnaire were usable. The method use in this study are reliability analysis, descriptive statistics, correlational analysis and regression analysis. The data is analyses using SPSS software version 14. The results show’s that all of the independent variable which is workload, organizational support and role conflict has a significant relationship with work-life balance. The most significant factor that affect work-life balance among employees in Johor Bahru is organizational support with 0.278

6,7-Dihydro-3H-1,4-diazepino[1,2,3,4-lmn][1,10]phenanthroline-3,9(5H)-dione

In the title compound, C15H12N2O2, the seven-membered ring bearing the three methyl­ene C atoms displays a puckered conformation, with the methyl­ene C atoms deviating from the plane of the benzene ring by 0.05 (1), 0.98 (1) and 1.04 (1) Å. The phenanthroline unit is not planar; the dihedral angles between this benzene ring and the other pyridyl rings are 9.62 (4) and 9.31 (4)°. The crystal packing is stabilized by π–π inter­actions between two phenanthroline ring systems, forming a centrosymmetric dimer with a centroid–centroid distance of 3.656 (1) Å

5,7-Dihy­droxy-3,6-dimeth­oxy-2-(4-meth­oxy­phen­yl)-4H-chromen-4-one monohydrate

The title compound, C18H16O7·H2O, is a flavonoid isolated from Dodonaea viscosa­. The benzopyran ring system of the flavonoid is essentially planar [maximum deviation = 0.025 (2) Å] and inclined at 5.83 (2)° to the attached benzene ring. The water of hydration is involved in extensive hydrogen bonding, assembling the mol­ecules into a supra­molecular network via classical inter­molecular O—H⋯O hydrogen bonding. The crystal structure is further stabilized by π–π stacking inter­actions [centroid–centroid distance between benzene rings = 3.564 (3) Å]

Diethyl 2,2′-(biphenyl-2,2′-diyldi­oxy)diacetate

In the title compound, C20H22O6, the mean planes through the benzene rings make a dihedral angle of 59.82 (7)° with each other. Weak inter­molecular C—H⋯O inter­actions together with π–π stacking inter­actions [centroid–centroid distance = 3.830 (1) Å] between benzene rings are observed in the crystal packing

Synergistic effects of Persicaria odorata (Daun Kesom) leaf extracts with standard antibiotics on pathogenic bacteria

Antibacterial activity of different types of P. odorata leaf extracts was evaluated in combination with standard antibiotics. Persicaria. odorata leaves were extracted with n-hexane (n-hex), dichloromethane (DCM) and methanol (MeOH). Each extract was applied on vancomycin (30μg), erythromycin (15μg) and gentamicin (10μg) discs, respectively. Disk diffusion method was used to evaluate the synergistic activity of each combination on Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, Streptococcus pneumoniae, Pseudomonas aeruginosa, Salmonella typhi, and Escherichia coli. Minimum inhibitory concentration (MIC) and gas chromatography mass spectrometry (GCMS) analysis was performed on the active extract. Synergistic effects seen were mainly from the n-hex+antibiotics combinations, mainly on the Gram-positive bacteria (7 additive, 5 antagonistic), with MIC range from 50 μg/ml to 100 μg/ml, as well as Gram-negative bacteria (2 additive, 2 indifferent, 5 antagonistic). In particular, synergism showed by the combination of n-hex+van were all additive against the susceptible bacteria. DCM extract combination showed synergistic effects on three Gram-positive species (S. aureus, S. epidermidis, S. pyogenes). Meanwhile, MeOH+antibiotics combination showed significant additive synergistic effects (p<0.05) on S. aureus and S. epidermidis. The major compounds of leaves extract were decanal and β-citral. n-Hex extract superiorly inhibited Gram-positive bacteria growth as compared to DCM and MeOH extracts. The additive synergistic property of the n-hex P. odorata extract could be further studied for possible use as an antibacterial agent

An Investigation of the Major Wheat Weeds in Different Zones of Dera Ismail Khan

On account of huge yield losses, weed infestation is a serious threat in wheat crops throughout the country. A comprehensive survey to find out the major weeds in wheat in Dera Ismail Khan was carried out during the crop season of 2012-13. Wheat fields at seed farms of Rakhmanghan, RakhZandani, Rata Kulachi and adjacent farmer’s fields to each seed farm were investigated. Data was collected at the peak growth stage of weeds and the quadratic method was used to record relative density (RD), relative frequency (RF), relative crowding coefficient (RCC) and importance value index (IVI). The results revealed that the major and most problematic weed of wheat at all the locations was Avena fatua (wild oat) on account of having maximum IVI at Rakh Manghan (78.51 & 77.44), Rata Kulachi (77.82 & 77.54) and Rakh Zandani (77.51 & 77.53) seed Farms and Farmer’s fields respectively. Rumex dentatus (dock) and Convolvulus arvensis (Lehli) were the second and third abundantly occurring weeds at almost all the seed farms and farmer fields on account of having the second and third highest IVI values at all the locations. Therefore Avena fatua (wildoat), Rumex dentatus (dock) and Convolvulus arvensis (lehli) seed were collected to find out the yield losses through further experimentation