28 research outputs found

    Effect of number of baffles on flow and pressure drop in a shell side of a shell and tube heat exchangers

    Get PDF
    The effect of number of baffles on flow and pressure drop on a shell side of shell-andtube heat exchangers was studied. In the present study, a set of CFD simulations using FLUENT version 17.0 from ANSYS were used to analyze the flow in the single shell and single tube pass heat exchangers consists of 20 mm diameter of tubes in staggered configuration with a variable number of baffles. The simulations were undertaken to inform on how the fluid flowed within the shell side of shell-and-tube heat exchangers. The results show that the variable number of baffles and baffle spacing in a heat exchanger strongly affect the flow pattern and pressure drop. This is consistent with other published data

    Effect of number of baffles on flow and pressure drop in a shell side of a shell and tube heat exchangers

    Get PDF
    The effect of number of baffles on flow and pressure drop on a shell side of shell-andtube heat exchangers was studied. In the present study, a set of CFD simulations using FLUENT version 17.0 from ANSYS were used to analyze the flow in the single shell and single tube pass heat exchangers consists of 20 mm diameter of tubes in staggered configuration with a variable number of baffles. The simulations were undertaken to inform on how the fluid flowed within the shell side of shell-and-tube heat exchangers. The results show that the variable number of baffles and baffle spacing in a heat exchanger strongly affect the flow pattern and pressure drop. This is consistent with other published data

    Pengembangan Tortila Berkalsium sebagai Alternatif Pangan Diet Casein Free-Gluten Free pada Industri Kecil dengan Metode Value Engineering

    Full text link
    The number of people with autism increased 56% in 1998 – 2013, and it was a global problem. People with autism need special treatments and CFGF diet (casein free, gluten free) was one of those treatments. That's why, the development The calcium content was expected to substitute the calcium from dairy consumption, which shouldn't be consumed by people with autism. The method used in this product development was value engineering which separated in three steps: information, creativity, and analysis steps. Respectively, this research was also further completed with chemical The goal of this research was to design some product implemented in small scale industry. Respondends and panelist in this research were consisted of students and teachers. They acted as the market of the product, especially as a part of general society. This product were designed to provide CFGF snack for people with autism, and those who need CFGF diet. But this product was not limited to that market, it can be consumed by general society not only for people with autism, hence the students and teachers were used. The research showed that the best concept was a product produced with to get 200 grams of dough. This product concept was also designed to be packed in big size gusset packaging materials and the chips was triangle-shaped with size of feasible to be produced in small scale industry

    Designing Control Points in UAV-Photogrammetry Mapping Using GNSS Concept to Produce Land Use Map (Case Study: Ciwidey Village, Bandung Regency, Indonesia)

    Get PDF
    Production of orhtophoto maps from UAV-photogrammetry method depend on aerial data and control points that are measured by GNSS method. Quality control of orhtophoto maps need comparison coordinate from Check Points and orthophoto maps coordinate to calculate the Root Mean Square Error (RMSE). So that, quality of control points is important in aerial data processing. In this research, baseline length, observation time, measurement method, and area characteristics will be discussed based on the GNSS concept to fulfill the accuracy standard of control points from the American Society of Photogrammetry and Remote Sensing (ASPRS). The shorter baseline length, and the loner observation time, accuracy should be increase significantly, but it depends on the field situation and the accuracy required for the user. After all, the result of this research is to obtain control points design based on GNSS concept in Ciwidey Village, Bandung Regenc

    Multifunctionality of silver closo-boranes

    Get PDF
    Silver compounds share a rich history in technical applications including photography, catalysis, photocatalysis, cloud seeding and as antimicrobial agents. Here we present a class of silver compounds (Ag2B10H10 and Ag2B12H12) that are semiconductors with a bandgap at 2.3?eV in the green visible light spectrum. The silver boranes have extremely high ion conductivity and dynamic-anion facilitated Ag(+) migration is suggested based on the structural model. The ion conductivity is enhanced more than two orders of magnitude at room temperature (up to 3.2?mS?cm(-1)) by substitution with AgI to form new compounds. Furthermore, the closo-boranes show extremely fast silver nano-filament growth when excited by electrons during transmission electron microscope investigations. Ag nano-filaments can also be reabsorbed back into Ag2B12H12. These interesting properties demonstrate the multifunctionality of silver closo-boranes and open up avenues in a wide range of fields including photocatalysis, solid state ionics and nano-wire production

    Designing Control Points in UAV-Photogrammetry Mapping Using GNSS Concept to Produce Land Use Map (Case Study: Ciwidey Village, Bandung Regency, Indonesia)

    No full text
    Production of orhtophoto maps from UAV-photogrammetry method depend on aerial data and control points that are measured by GNSS method. Quality control of orhtophoto maps need comparison coordinate from Check Points and orthophoto maps coordinate to calculate the Root Mean Square Error (RMSE). So that, quality of control points is important in aerial data processing. In this research, baseline length, observation time, measurement method, and area characteristics will be discussed based on the GNSS concept to fulfill the accuracy standard of control points from the American Society of Photogrammetry and Remote Sensing (ASPRS). The shorter baseline length, and the loner observation time, accuracy should be increase significantly, but it depends on the field situation and the accuracy required for the user. After all, the result of this research is to obtain control points design based on GNSS concept in Ciwidey Village, Bandung Regenc

    Increasing hydrogen density with the cation-anion pair BH4--NH4+ in perovskite-type NH4Ca(BH4)3

    No full text
    A novel metal borohydride ammonia-borane complex Ca(BH4)2·NH3BH3 is characterized as the decomposition product of the recently reported perovskite-type metal borohydride NH4Ca(BH4)3, suggesting that ammonium-based metal borohydrides release hydrogen gas via ammonia-borane-complexes. For the first time the concept of proton-hydride interactions to promote hydrogen release is applied to a cation-anion pair in a complex metal hydride. NH4Ca(BH4)3 is prepared mechanochemically from Ca(BH4)2 and NH4Cl as well as NH4BH4 following two different protocols, where the synthesis procedures are modified in the latter to solvent-based ball-milling using diethyl ether to maximize the phase yield in chlorine-free samples. During decomposition of NH4Ca(BH4)3 pure H2 is released, prior to the decomposition of the complex to its constituents. As opposed to a previously reported adduct between Ca(BH4)2 and NH3BH3, the present complex is described as NH3BH3-stuffed α-Ca(BH4)2

    Neuroimaging Findings in Patients with Covid-19 in Indonesia

    Full text link
    Background: Covid-19 caused by the SARS-CoV-2 virus has spread worldwide, including Indonesia. Neurological manifestations has also been reported in Covid-19 positive patients. Yet documentation of their neuroimaging findings are lacking, especially in Indonesia. Objective: To understand neuroimaging findings in Covid-19 positive patients Methods: An observational study from medical record of Covid-19 positive patients in our hospital who developed abnormal neurologic manifestations and were followed up by neuroimaging examination from May to August 2020. Covid-19 positive diagnosis was confirmed from nasopharyngeal swab using the Real Time Polymerase Chain Reaction (RT-PCR). Neurological examination was performed by a neurologist, who then referred patients for neuroimaging examination using CT or MRI. Radiological expertise was performed by a radiologist. Results: A total of 288 patients who are Covid-19 positive from nasopharyngeal RT-PCR swab admitted to our hospital from May to August 2020. Ten patients (3.5%) had abnormal neurologic manifestations and further neuroimaging examination follow up. Range of age 33-72 years old and slight male predominance (60%). Frequent clinical symptoms were decreased consciousness (40%), altered mental status (30%) and tremors (20%). Neuroimaging findings were large vessel occlusion (30%), vasculitis (20%), post hipoxic leucoencephalopathy (10%), basal ganglia encephalopathy (10%), non specific small vessel ischemia changes and negative findings (30%). Most patients were discharged with clinical improvement (60%), while 40% mortality rate were seen in patient with large vessel occlusion (30%) and vasculitis (10%). Conclusion: Neuroimaging findings in Covid-19 positive patients were large vessel occlusion (LVO), vasculitis, post hipoxic leucoencephalopathy and basal ganglia encephalopathy Keywords: Covid-19, neurological, manifestation, neuroimagin
    corecore