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In this study, exergy and energy analysis are studied to understand and examine the heating unit performance in Nag Hammadi Fiber Board Company (NFB) with a capacity of 22 MW. The heating unit utilizes natural gas and biofuel together, where the combustion chamber is designed to burn natural gas and wood dust at the same time to decrease the operating cost of the heating unit. The main purpose of heating unit is to burn natural gas and biofuel to supply the manufacturing processes in fiber board production line by hot flue gases for dryer unit and saturated steam for the digestion unit. the heating unit consists of combustion chamber, heat exchanger and steam generator. There is no heat transfer inside the combustion chamber except heat losses through the wall of the combustion chamber. The exergy and energy efficiencies for combustion chamber are found to be 74 % and 42 %, respectively, for heat exchanger are found to be 85 % and 51 %, respectively, for steam generator are found to be 78 % and 30 %, respectively and for heating unit totally are found to be 64 % and 31 %, respectively. This study is carried out to identify and quantify the exergy and energy losses in the heating unit components.

Background: Depression is a devastating disease that adversely affects all aspects of one's existence. There is some evidence that low circulating concentration of serum 25hydroxyvitamin D [25(OH)D], the marker for Vitamin D status, is associated with mood disorders, including major depresssive disorder. Aim of Study:The aim of this work is to investigate the association between serum Vitamin D concentrations and depression and to evaluate the correlation between the concentrations of Vitamin D and severity of depression. Subjects and Methods:This study was conducted on 66 patients suffering from depression, and 22 apparently healthy individuals as controls. Complete psychiatric interview; with application of Beck Depression Inventory II (BDI-II) Scale for diagnosis and assessment of the severity of depression was done. Laboratory investigations including kidney function tests, liver function tests,serum total calcium,phosphorus and serum Vitamin D (25-OH Vitamin D3/D2) was done for all subjects.Results: 21, 23 and 22 patients had mild, moderate and severe depression respectively. There was statistically very high significant decrease in Vitamin D level in patients group compared to control group. In patients group, 40.9% of patients had Vitamin D deficiency (serum 25(OH]D <12ng/mL), 33.3% had Vitamin D insufficiency (serum 25(OH]D ranged from 12 to 20ng/mL), and 25.8% had sufficient level of Vitamin D (serum 25(OH]D >20ng/mL). There was statistically significant decrease of Vitamin D levels in female patients group compared to male patients group. There was statistically significant negative correlation between BDI-II score and Vitamin D level in patients group. Conclusion:The finding of this study revealed evidence of an association between low 25(OH)D, a marker of Vitamin D status, and depression, suggesting a direct effect of Vitamin D on development of depression.There was an association between low Vitamin D status and the severity of depression.Vitamin D deficiency was more pronounced in female patients than male patients.

In this study, energy and exergy analysis are studied to examine and understand the performance of the combustion chamber (furnace) of the heating unit in Nag Hammadi fiber board Company (NFB) with a capacity of 22 MW, utilizing natural gas and biofuel together where the combustion chamber is designed to burn natural gas and wood dust at the same time to decrease the operating cost of the heating unit. The main purpose of combustion chamber is to burn natural gas and biofuel to supply the heating unit by high temperature combustion products. There is no heat transfer inside the combustion chamber except heat losses through the wall of the combustion chamber. The purpose of the heating unit in the factory is to supply the manufacturing processes by hot flue gases for dryer unit, hot thermal oil for hot press system and saturated steam for the digester. The energy and exergy efficiencies are found to be 69 % and 28 %, respectively. This study is carried out to identify and quantify the energy and exergy losses in the combustion chamber.