Display omitted
► The low cost adsorbents were manufactured by using zeolite, bentonite and kaolin. ► The strength and lead adsorption was optimized to fabricate applicable adsorbents. ► The removal ...of lead by manufactured ring without using filtration is the novelty of study. ► The obtained results can be useful in industrial practice.
Recently several kinds of low-cost adsorbents were developed for the extreme environmental and waste treatment processes. The adsorption capacity and physico-mechanical properties of adsorbent are basically affected by mixing ratio of the used materials. These requirements cause to apply the technique of experiment to optimize mentioned properties. In the present investigation commercial zeolite, bentonite and kaolin were used in experimental design algorithm due to their abilities in removal of heavy metal ions. Different amounts of used powders were mixed according to mixture design algorithm and shaped by extrusion technique in the form of Raschig ring. The test rings were calcined at 600 and 700
°C after drying in laboratory oven and characterized by determining porosity, diametrical compressive strength and adsorption capacity. In order to manufacture applicable adsorbent, the response surface analysis method was used to optimize mixing ratio of materials. The investigation was concluded that the strength and adsorption capacity can be simultaneously optimized by the addition of 66.67, 29.17 and 4.16
wt.% zeolite, bentonite and kaolin respectively. In the next part of work, the kinetics and adsorption isotherm of lead on selected composition was mathematically investigated. The Langmuir isotherm and pseudo second order kinetic model showed the acceptable accuracy in prediction of adsorption data. The possibility of lead immobilization by fabricated rings can be useful in industrial practice.
Display omitted
► Weibull analysis is a powerful tool to improve the extrusion of zeolite-based adsorbents. ► Mixture design was successfully used to optimizing the mixing ratio of starting ...materials. ► Presented algorithms permit to consider the technical limits in fabrication of adsorbent. ► The obtained results can be useful in industrial practice.
In the production of zeolite-based adsorbents the inorganic binders such as bentonite and kaolin are normally used to extrude the solid in different shapes such as Raschig ring. In this investigation, statistical combinations of a three-component mixture were designed to achieve synergetic values of mechanical characteristics and lead removal efficiency. The adsorbents in the form of Raschig ring were shaped by a single screw extruder and calcined at different temperatures after drying in laboratory oven. The adsorbent properties such as porosity, compressive strength and removal efficiency were measured. The response surface algorithm was applied to analyze the obtained data. The feasibility of Weibull statistical theory was examined to determine the reliability of adsorbents. The results were very satisfactory for characterizing and predicting the reliability and manufacturing technical factors. The best calcination temperature was determined to simultaneously optimize removal efficiency and mechanical characteristics. However, the Weibull modulus should be considered for fabricating reliable adsorbent. According the laboratory experiments and statistical algorithms used in this study, the suitable combination region in which the ring acts as a good adsorbent were determined. It is concluded that the use of these procedures can be important tools to manufacture reliable adsorbent. The obtained results were confirmed by scanning electron microscopy observations.
The reaction
pp→
p
f
p
s
(
K
+
K
−
K
+
K
−) in which the
K
+K
−K
+K
−
system is centrally produced has been studied at 450 GeV/c.
φφ production has been found to dominate this reaction and is ...compatible with being produced by double Pomeron exchange. An angular analysis of the
φφ system favours
J
PC
=2
++ and its
dP
T
dependence is similar to that observed for glueball candidates.
An analysis of the centrally produced
π
+
π
− and
π
+
π
−
π
+
π
− mass spectra from the WA76 and WA91 experiments is presented, which shows that in the
π
+
π
−
π
+
π
− channel there are two new ...states, the
f
0(1450) and
f
2(1900). There is another new state in the
π
+
π
− channel with
M = 1497 ± 30 MeV and
Γ = 199 ± 30 MeV, which is compatible with the
f
0(1520) observed by the Crystal Barrel experiment. Another interpretation is discussed, where the 1450 and 1497 GeV structures are explained as being due to an interference effect between the
f
0(1365) and
f
0(1520).
Leukemoid reaction is defined by a leukocyte level above 50 x 10
3
/µL with a predominance of mature neutrophils and the presence of immature granulocytic forms in the peripheral blood (left shift). ...We report a case of a 36-year-old woman with severe coronavirus disease 2019 (COVID-19) infection admitted to the ICU with a leukocytosis of 70.9 x 10
3
/µL white blood cells (WBC) throughout her hospitalization. A left shift with bandemia along with toxic granulations was also noticed and further investigation excluded more commonly known causes. A presumptive diagnosis of leukemoid reaction was made secondary to COVID-19 infection; however, it could not be confirmed since workup for lymphoproliferative disorders could not be performed as the patient passed away. The leukemoid reaction could be associated with severe COVID-19 infection; however, more data are needed to evaluate this association.
Posterior reversible encephalopathy syndrome (PRES) is a neurological syndrome characterized by acute encephalopathy due to different medical conditions. This syndrome may present with a wide ...spectrum of neurological symptoms including headache, disorders of consciousness, visual changes, seizures, and focal neurological deficits, in addition to nonspecific symptoms such as nausea and vomiting. Neuroimaging findings of bilateral cortical and subcortical brain edema involving the parieto-occipital regions are a hallmark of the disease. We present a case report of an eight-year-old boy who complained of headache and vomiting for 20 days until the discovery of severely high blood pressure (BP). He developed altered mental status, hemiplegia, loss of visual field, and seizure, requiring transfer to the intensive care unit. Magnetic resonance imaging of the brain showed hyperintense signals in the bilateral cortical and subcortical parieto-occipital areas. The BP measure of the extremities recognized a hypertensive upper extremity and normotensive lower extremity, and an MRI angiography was consistent with coarctation of the aorta (CoA). The fundoscopic exam showed no abnormalities. The diagnosis was kept as PRES secondary to a hypertensive emergency. Later, stenting of the aorta was performed, improving overall symptoms leaving a sequel loss of peripheral vision.
During the SARS-CoV-2 pandemic, various rashes associated with COVID-19 infection have been reported, including urticaria. Urticaria is a limited and usually benign condition, presenting as pruritic ...wheals, with or without edema. A 39-year-old woman presented with a pruritic rash on her arms spreading to her trunk and face over two days, followed by headache, nausea, vomiting, abdominal discomfort, diarrhea, myalgia, arthralgia, anosmia, and dyspepsia for three days. Fever, dry cough, and odynophagia started on the day of the consult. The patient had a history of hypertension but denied a history of atopic conditions, similar previous presentations, or recent ingestion of new medications. SARS-CoV-2 COVID-19 PCR testing was positive. She was prescribed oral antihistamine for the itching and was discharged. During a follow-up after two weeks, the patient was asymptomatic with complete resolution of the rash on day 7 of symptoms. Knowing the cutaneous manifestations of COVID-19 can aid in the early identification of this disease and prevent misdiagnosis. The presence of cutaneous manifestations in COVID-19 is suggested to be related to disease severity, but data are needed to study any prognostic value of dermatologic manifestations in COVID-19.
A study of the centrally produced
p
p
,
p
pπ
0
,
p
pπ
+π
−
and
Λ
Λ
channels has been performed in
pp collisions using an incident beam momentum of 450 GeV/c. No significant new structures are ...observed in the mass spectra, however, important new information on the production dynamics is obtained. A systematic study of the production properties of these systems has been performed and it is found that these systems are not produced dominantly by double Pomeron exchange.
PDF
