Experimental analysis of particle clustering in moderately dense gas–solid flow

In collisional gas–solid flows, dense particle clusters are often observed that greatly affect the transport properties of the mixture. The characterisation and prediction of this phenomenon are challenging due to limited optical access, the wide range of scales involved and the interplay of different mechanisms. Here, we consider a laboratory setup in which particles fall against upward-moving air in a square vertical duct: a classic configuration in riser reactors. The use of non-cohesive, monodispersed, spherical particles and the ability to independently vary the solid volume fraction ( $\varPhi _V = 0.1\,\% - 0.8\,\%$ ) and the bulk airflow Reynolds number ( $Re_{bulk} = 300 - 1200$ ) allows us to isolate key elements of the multiphase dynamics, providing the first laboratory observation of cluster-induced turbulence. Above a threshold $\varPhi _V$ , the system exhibits intense fluctuations of concentration and velocity, as measured by high-speed imaging via a backlighting technique which returns optically depth-averaged fields. The space–time autocorrelations reveal dense and persistent mesoscale structures falling faster than the surrounding particles and trailing long wakes. These are shown to be the statistical footprints of visually observed clusters, mostly found in the vicinity of the walls. They are identified via a percolation analysis, tracked in time, and characterised in terms of size, shape, location and velocity. Larger clusters are denser, longer-lived and have greater descent velocity. At the present particle Stokes number, the threshold $\varPhi _V \sim 0.5$ % (largely independent from $Re_{bulk}$ ) is consistent with the view that clusters appear when the typical interval between successive collisions is shorter than the particle response time.

Identifikasi Salmonella Sp Pada Saus Cabai Pentolan yang Diperjualbelikan Di Kecamatan Mamajang Kota Makassar

Sauce is a flavoring ingredient that is usually added to food. In the chili sauce processing process, it is possible that the raw materials used are not washed clean and the place used to store chili sauce is in the form of bottles or containers that do not undergo a sterilization process after use. One of the bacteria that contaminates chili sauce is Salmonella sp which can cause digestive tract disorders. The purpose of the study was to identify Salmonella sp in the pentolan chili sauce that was traded in the Mamajang sub-district, Makassar city, which was a laboratory observation using research methods, namely culture and biochemical tests. The research sample used was pentolan chili sauce that was traded in the Mamajang sub-district of Makassar city as many as 10 samples with the sampling technique of random sampling. Based on the research that has been done from 10 samples of pentolan chili sauce, positive results were obtained for Salmonella sp. It can be concluded that the pentolan chili sauce sold in the Mamajang district of Makassar city has been contaminated by Salmonella sp.

Analisis Kualitatif Residu Pestisida Pada Bahan Pangan Dengan Menggunakan Metode Kromatografi Lapis Tipis (KLT)

Vegetables and fruits are foodstuffs whose cultivation process requires pesticides. In addition to farmers who apply pesticides, pesticide poisoning can also be experienced by people who consume agricultural products including vegetables through the pesticide residues contained in them, so that it will have a negative impact on human health who consume them continuously. The purpose of the study was to determine the presence of pesticide residues in foodstuffs. This research is a laboratory observation with a simple random sampling technique. In this study, a qualitative analysis of organophosphate and carbamate pesticide residues in food ingredients was carried out using the Thin Layer Chromatography (TLC) method. Based on the results of the study, from 15 (fifteen) samples of vegetables, no organophosphate chlorpyrifos pesticide content was detected, but the carbamate group was detected in samples of spinach, cabbage, and carrots marked with spots and the Rf value was the same as the Furadan standard. Thus, it is hoped that the community will wash the vegetables before they are processed and consumed.

Laboratory observation of interior surface heat transfer at balcony door

This paper informs about laboratory experiments studying heat transfer phenomena at the interior side of balcony doors. A well-insulated testing space representing a typical room with a balcony door equipped with floor heating and warm air heating was used. In the first step, an opaque panel with similar thermal transmittance as a triple glazed balcony door was installed in the opening for reference. A combination of temperature measurements and particle imaging velocimetry (PIV) was used here to study the surface heat transfer in detail for both types of space heat distribution and obstacles by curtains. From the measured data, the surface heat transfer coefficient along the height of the door was evaluated and discussed.

A Qualitative Investigation of the Interactions of Students with Graduate and Undergraduate TAs in General Chemistry Laboratories

A new teaching assistant model was adopted and qualitatively assessed for the general chemistry laboratory, in which both an undergraduate and a graduate teaching assistant provided instruction to students during the lab. Verbal interactions between graduate and undergraduate teaching assistants were recorded, transcribed, and coded using the modified Laboratory Observation Protocol for Undergraduate STEM (LOPUS). The codes were applied to capture how discussions, questioning, and explanations were conducted. In addition, the content discussed was coded to identify specific areas that pose challenges for students. Sizable differences were not observed between the number of interactions of the initiation, explanation, and questioning codes between graduate and undergraduate teaching assistants. Of the interactions, 77% focused on questions and discussions regarding the experimental setup. Discussions on the implications with regards to the effective use of undergraduate and graduate teaching assistants in chemistry laboratories are included.

IDENTIFIKASI TELUR CACING NEMATODA USUS SOIL TRANSMITTED HELMINTH (STH) PADA MASYARAKAT DI PULAU LAE-LAE KOTA MAKASSAR

ABSTRACT Communities on Lae-Lae Island, Makassar City have sanitation facilities that are still poor and very limited with quality far from health standards. This causes people who live in these islands to face various health problems, one of which is the risk of being infected with eggs of intestinal nematode worms Soil-Transmitted Helminths (STH). This study aims to identify the eggs of the intestinal nematode worm Soil Transmitted Helminthes in the feces of people on Lae-Lae Island, Makassar City. This type of research is a laboratory observation with a purposive sampling technique of 10 stool samples. Based on the results of research that has been carried out on 10 faecal samples, it was found 1 positive stool sample for Trichuris trichura worm eggs with distinctive egg-shaped characteristics such as the shape of crock worm eggs or wine barrels and at both ends there are two mucoid plugs. The egg wall is brown from the color of the bile at both ends, it is clear, while the other 9 stool samples are negative the type of worm Trichuris trichura and 9 other samples were negative.

A person-centered approach to understanding child temperament at ages 3 and 6

Person-centered analyses, such as latent profile analysis, provide an approach to assessing individual differences in child temperament that aligns with typological theory and is well positioned for translation to applied settings. In a community sample, latent profile analysis was conducted using seven temperament traits assessed through laboratory observation when children were three- and six-years-old. At age 3, a four-class model fit best and subgroups were labeled “typical,” “sluggish,” “surgent,” and “dysregulated,” based on the pattern of class-specific means. A five-class model fit best at age 6 and subgroups were labeled “typical,” “sluggish,” “outgoing,” “active-impulsive” and “negative affect.” Associations between class membership and mother-reported temperament traits, concurrently assessed, were mostly consistent with the class identities. Comparison of subgroup membership across waves generally demonstrated patterns of continuity across groups characterized by similar trait patterns. This paper provides an illustrative guide for temperament researchers in the implementation of latent profile analysis, addressing important methodical considerations. Increased utilization of person-centered approaches like latent profile analysis could lead to important advances in the study of child temperament, such as improved understanding of the continuity of temperamental styles and more targeted risk assessment.

Comprehensive analysis of male-free reproduction in Monomorium triviale (Formicidae: Myrmicinae)

We report comprehensive evidence for obligatory thelytokous parthenogenesis in an ant Monomorium triviale. This species is characterized by distinct queen–worker dimorphism with strict reproductive division of labor: queens produce both workers and new queens without mating, whereas workers are completely sterile. We collected 333 nests of this species from 14 localities and three laboratory-reared populations in Japan. All wild queens dissected had no sperm in their spermathecae. Laboratory observation confirmed that virgin queens produced workers without mating. Furthermore, microsatellite genotyping showed identical heterozygous genotypes between mothers and their respective daughters, suggesting an extremely low probability of sexual reproduction. Microbial analysis detected no bacterial genera that are known to induce thelytokous parthenogenesis in Hymenoptera. Finally, the lack of variation in partial sequences of mitochondrial DNA among individuals sampled from across Japan suggests recent rapid spread or selective sweep. M. triviale would be a promising model system of superorganism-like adaptation through comparative analysis with well-studied sexual congeners, including the pharaoh ant M. pharaonis.